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Stage 2C Environmental Investigation - Human Health Risk Assessment – 2017

Army Aviation Centre Oakey (AACO), Oakey QLD Department of Defence

1 December 2017 60533675 Revision 0 Final

AECOM Stage 2C Environmental Investigation - Human Health Risk Assessment - 2017 – Army Aviation Centre Oakey (AACO), Oakey QLD

Revision 0 – 01-Dec-2017 Prepared for – Department of Defence – ABN: 68 706 814 312

Stage 2C Environmental Investigation - Human Health Risk Assessment - 2017 Army Aviation Centre Oakey (AACO), Oakey QLD

Client: Department of Defence

ABN: 68 706 814 312

Prepared by

AECOM Australia Pty Ltd Level 8, 540 Wickham Street, PO Box 1307, Fortitude Valley QLD 4006, Australia T +61 7 3553 2000 F +61 7 3553 2050 www.aecom.com ABN 20 093 846 925

01-Dec-2017

Job No.: 60533675

AECOM in Australia and New Zealand is certified to ISO9001, ISO14001 AS/NZS4801 and OHSAS18001.

© AECOM Australia Pty Ltd (AECOM). All rights reserved.

AECOM has prepared this document for the sole use of the Client and for a specific purpose, each as expressly stated in the document. No other party should rely on this document without the prior written consent of AECOM. AECOM undertakes no duty, nor accepts any responsibility, to any third party who may rely upon or use this document. This document has been prepared based on the Client’s description of its requirements and AECOM’s experience, having regard to assumptions that AECOM can reasonably be expected to make in accordance with sound professional principles. AECOM may also have relied upon information provided by the Client and other third parties to prepare this document, some of which may not have been verified. Subject to the above conditions, this document may be transmitted, reproduced or disseminated only in its entirety.



Quality Information

Document Stage 2C Environmental Investigation - Human Health Risk Assessment - 2017

Ref 60533675

Date 01-Dec-2017

Prepared by Cindy Cheung & Michael Archer

Reviewed by Amanda Lee

Revision History

Rev Revision Date Details Authorised

Name/Position Signature

A 01-Sep-2017 Preliminary Draft Frances Lee Technical Director

B 25-Sep-2017 Draft Frances Lee Technical Director

C 09-Oct-2017 Revised Draft Frances Lee Technical Director

D 24-Nov-2017 Final Draft Frances Lee Technical Director

0 01-Dec-2017 Final Frances Lee Technical Director

Distribution List:

Rev Revision Date Details Distribution

A 01-Sep-2017 Preliminary Draft Department of Defence

B 25-Sep-2017 Draft Department of Defence

C 09-Oct-2017 Revised Draft Department of Defence

D 24-Nov-2017 Final Draft Department of Defence

0 01-Dec-2017 Final Department of Defence



Table of Contents Executive Summary vi 1.0 Introduction 1

1.1 This Report 1 1.2 Background 3 1.3 Investigation Area Definition 7 1.4 Objective 8 1.5 Framework and Methodology 8 1.6 Scope of Work 10

1.6.1 Step 1: Issues Identification 10 1.6.2 Step 2: Data Collection, Evaluation and Conceptual Site Model 10 1.6.3 Step 3: Exposure Assessment 11 1.6.4 Step 4: Toxicity Assessment 11 1.6.5 Step 5: Risk Characterisation 11

2.0 Site Identification and Environmental Setting 12 2.1 Site Location and Surrounding Land Use 12

2.1.1 Regional Oakey District 12 2.1.2 The Site 12 2.1.3 Land Use 12

2.2 Topography 12 2.3 Climate 13 2.4 Geology 13 2.5 Hydrogeology 14 2.6 Groundwater Management and Use 17

2.6.1 On-Site Groundwater Use 17 2.6.2 Off-Site Groundwater Use 17

2.7 Surface Water 18 2.7.1 Regional Drainage System 18 2.7.2 On-Site Surface Water 18 2.7.3 Oakey Town Water Supply 19

2.8 Water Quality Objectives and Environmental Values 19 3.0 Issues Identification 21

3.1 Rationale for Undertaking the HHRA 21 3.2 Stakeholders 22 3.3 HHRA Objectives 22 3.4 Risk Management Decisions 22

4.0 Data Collection, Evaluation and Conceptual Site Model 23 4.1 Data Collection 23

4.1.1 Previous Investigations 23 4.1.2 Data Presented in this Report 24

4.2 Data Evaluation 25 4.2.1 Data Quantity 25 4.2.2 Data Quality 30 4.2.3 Data Evaluation Conclusion 31 4.2.4 Data Gaps 31

4.3 Nature and Extent of PFAS Impacts 37 4.3.1 Groundwater 37 4.3.2 Review of Groundwater PFAS Detection Zones Adopted in the HHRA 40 4.3.3 Soil 43 4.3.4 Surface Water and Sediment 48

4.4 Biota Sampling Analysis and Results 52 4.4.1 Historical Biota Investigations 52 4.4.2 2017 Biota Investigation 56 4.4.3 Summary of PFAS Detected in Biota Samples 56 4.4.4 Consideration of Biota Samples in the HHRA 59

4.5 Other Published Data 67



4.5.1 Sample Collection 67 4.5.2 Analytical Methodology 67 4.5.3 Summary of Results 67

4.6 Distribution of PFAS within Different Media 69 4.7 Selection of PFAS for Quantitative Assessment in the HHRA 74 4.8 Conceptual Site Model 74

4.8.1 Sources 75 4.8.2 Potential Human Receptors 76 4.8.3 Existing Exposure Mitigation Measures 76 4.8.4 Potentially Complete Human Exposure Pathways 77

5.0 Exposure Assessment 91 5.1 Human Behavioural Exposure Assumptions 91

5.1.1 Typical vs. Upper Range Exposure 91 5.1.2 Sources of Exposure Assumptions 91 5.1.3 General Exposure Parameters 96 5.1.4 Food Ingestion Rates 97 5.1.5 Intakes via Infant Ingestion of Breast Milk 97

5.2 Chicken Egg PFAS Residue Study 98 5.2.1 PFAS Transfer Factors for Laying Hens 98 5.2.2 Reduction in PFAS in Eggs After Exposure Ceases 99

5.3 Plant PFAS Uptake Study 100 5.4 Equations for Estimation of Exposure 100 5.5 Exposure Point Concentrations 100

5.5.1 EPC Based on Measured Concentrations of PFAS 100 5.5.2 EPC Based on Modelled Concentrations of PFAS 103 5.5.3 Media Sampled but Not Used to Evaluate Human Exposures 105 5.5.4 Statistical Approach Adopted When Selecting EPC 106 5.5.5 Summary of Adopted EPC 106

6.0 Toxicity Assessment 121 6.1 Hazard Identification 121 6.2 Dose-Response Assessment 122

6.2.1 PFOS 123 6.2.2 PFOA 123 6.2.3 PFHxS 123 6.2.4 PFHxA 123 6.2.5 Summary 123

6.3 Background Exposure 124 7.0 Risk Characterisation 126

7.1 Introduction 126 7.2 Hazard Quotient and Hazard Index 126

7.2.1 Overview 126 7.2.2 Cumulative Assessment of PFOS and PFHxS 127 7.2.3 Estimated HQ and HI 127

7.3 Summary of HI for Pathways Currently Complete in IA 128 7.3.1 Cumulative HI for Potentially Complete Pathways Excluding Drinking

Groundwater 128 7.3.2 Cumulative HI for Pathways Not Currently Subject to Precautionary

Recommendations 129 7.4 Risk Estimate Evaluation for Individual Pathways 130

7.4.1 Intakes Based on Typical Exposure Parameters 130 7.4.2 Intakes Based on Upper Range Exposure Parameters 132

7.5 Relative Contribution of Individual Pathways 134 7.6 Assessment of Human Blood Serum Data 147 7.7 Summary 147

8.0 Uncertainty Evaluation and Sensitivity Assessment 149 8.1 Uncertainties 149 8.2 Potential Future Uses of Water for Aquaculture 149 8.3 Sensitivity Assessment 152



9.0 Managing Future PFAS Exposure 166 10.0 Conclusions 167 11.0 References 179 12.0 Limitations 185

Appendix A Figures A

Appendix B Tables B

Appendix C Biota Sampling and Analysis C

Appendix D Biota Sample Laboratory Reports and QAQC D

Appendix E Community Surveys E

Appendix F Exposure Assumptions F

Appendix G Exposure Equations G

Appendix H PFAS Ratios H

Appendix I Toxicity Profiles I

Appendix J Risk Estimates J

Appendix K Sensitivity Assessment K

Appendix L Chicken Egg PFAS Residue Study L

Appendix M PFAS Uptake by Plants M



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List of Acronyms

Acronym Definition

µg/kg micrograms per kilogram

µg/kg/day micrograms per kilogram per day

µg/L micrograms per litre

6:2 FtS 6:2 fluorotelomer sulfonate

8:2 FtS 8:2 fluorotelomer sulfonic acid

AACO Army Aviation Centre Oakey

ABS Australian Bureau of Statistics

ADI Acceptable daily intake

AFFF Aqueous film forming foam

AHD Australian height datum

ALS ALS Laboratory Group

ASC NEPM 2013 National Environment Protection (Assessment of Site Contamination) Measure 1999 (as amended 2013)

ATSDR Agency for Toxic Substances and Disease Registry

BMD Benchmark dose

BMDL10 Benchmark dose lower confidence limit for a 10% response

BoM Bureau of Meteorology

bw Body weight

CAR Constitutive androstane receptor

CoPC Contaminants of potential concern

CSM Conceptual site model

DA Detection Area

DNRM Department of Natural Resources and Mines

DPI NSW Department of Primary Industries

ECs Exposure concentrations

EFSA European Food Safety Authority

EPC Exposure point concentration

ERA Ecological risk assessment

ESA Environmental site assessment

EtFOSA N-Ethyl perfluorooctane sulfonamide

EtFOSAA N-Ethyl perfluorooctane sulfonamidoacetic acid

EtFOSE N-Ethyl perfluorooctane sulfonamidoethanol

FSANZ Food Standards Australia New Zealand

HHRA Human health risk assessment

HI Hazard Index

HLC Henry’s Law Constant



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Acronym Definition

HQ Hazard quotient

IA Investigation Area

IPCS International Programme on Chemical Safety

km kilometre(s)

LNAPL Light non-aqueous phase liquid

LOAEL Lowest observed adverse effect level

LOR Limit of reporting

m metre(s)

m bgl metres below ground level

m btoc metres below top of casing

Mass DEP Massachusetts Department of Environmental Protection

MDBA Murray Darling Basin Authority

MeFOSA N-Methyl perfluorooctane sulfonamide

MeFOSAA N-Methyl perfluorooctane sulfonamidoacetic acid

MeFOSE N-Methyl perfluorooctane sulfonamidoethanol

mg/kg milligrams per kilogram

mg/kg/day milligrams per kilogram per day

mg/L milligrams per litre

MOE Margin of exposure

NATA National Association of Testing Authorities

NHMRC National Health and Medical Research Council

NMI National Measurement Institute

NNPAS National Nutrition and Physical Activity Survey

NOAEL No Observed Adverse Effect Level

NSW DPI New South Wales Department of Primary Industries

PFAS Per- and poly-fluoroalkyl substances

PFBA Perfluorobutanoic acid

PFBS Perfluorobutane sulfonic acid

PFC Perfluorinated compounds

PFDA Perfluorodecanoic acid

PFDoDA Perfluorododecanoic acid

PFDS Perfluorodecane sulfonic acid

PFHpA Perfluoroheptanoic acid

PFHpS Perfluoroheptane sulfonic acid

PFHxA Perfluorohexanoic acid

PFHxS Perfluorohexane sulfonic acid

PFNA Perfluorononanoic acid



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Acronym Definition

PFOA Perfluorooctanoic acid

PFOS Perfluorooctane sulfonate

PFOSA Perfluorooctane sulfonamide

PFPeA Perfluoropentanoic acid

PFPeS Perfluoropentane sulfonic acid

PFTeDA Perfluorotetradecanoic acid

PFTrDA Perfluorotridecanoic acid

PFUnDA Perfluoroundecanoic acid

PPARα Peroxisome proliferator-activated receptor alpha

PXR Pregnane X receptor

QC Quality control

RAAF Royal Australian Air Force

RAGS Risk Assessment Guidance for Superfund

RfD Reference dose

RO Reverse osmosis

RSAF Republic of Singapore Air Force

TDI Tolerable daily intake

TRC Toowoomba Regional Council

TRV Toxicity reference value

UF Uncertainty factor

US EPA United States Environmental Protection Agency

VP Vapour pressure

WCEP NSW Government Williamtown Contamination Expert Panel

WHO World Health Organization

Extended Suite of PFAS

Australian Laboratory Services (ALS)

PFBS Perfluorobutane Sulfonic Acid

PFPeS Perfluoropentane sulfonic acid


PFHpS Perfluoroheptane sulfonic acid

PFOS Perfluorooctane Sulfonate

PFDcS Perfluorodecane sulfonic acid

PFBA Perfluorobutanoic acid

PFPeA Perfluoropentanoic acid

PFHxA Perfluorohexanoic Acid



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Australian Laboratory Services (ALS)

PFHpA Perfluoroheptanoic Acid

PFOA Perfluorooctanoic Acid

PFNA Perfluorononanoic Acid

PFDcA Perfluorodecanoic Acid

PFUnA Perfluoroundecanoic Acid

PFDoA Perfluorododecanoic Acid

PFTriA Perfluorotridecanoic Acid

PFTeA Perfluorotetradecanoic Acid

PFOSA Perfluorooctane sulfonamide

N-Me- FOSA N-Methyl-heptadecafluorooctane sulfonamide

N-Et- FOSA N-Ethyl-heptadecafluorooctane sulfonamide

N-Me- FOSE N-Methyl-heptadecafluorooctane sulfonamidoethanol

N-Et-FOSE N-Ethyl-heptadecafluorooctane sulfonamidoethanol

Me-FOSAA N-Methyl perfluorooctane sulfonamidoacetic acid

Et-FOSAA N-Ethyl perfluorooctane sulfonamidoacetic acid

4:2 FtS 4:2 Fluorotelomer sulfonic acid

6:2 FtS 6:2 Fluorotelomer sulfonate

8:2 FtS 8:2 Fluorotelomer Sulfonic Acid

10:2 FtS 10:2 Fluorotelomer sulfonic acid


National Measurement Institute (NMI)

PFPeA Perfluoro-n-Pentanoic Acid

PFHxA Perfluorohexanoic Acid

PFHpA Perfluoroheptanoic Acid

PFOA Perfluorooctanoic Acid

PFNA Perfluorononanoic Acid

PFDA Perfluoro Decanoic Acid

PFUdA Perfluoro Undecanoic Acid

PFDoA Perfluoro Dodecanoic Acid

PFBS Perfluorobutane Sulfonic Acid



v


National Measurement Institute (NMI)


PFOS Perfluorooctane Sulfonate

6:2FTS 6:2 Fluorotelomer sulfonate

8:2 FtS 8:2 Fluorotelomer Sulfonic Acid



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Executive Summary

Introduction

AECOM Australia Pty Ltd (AECOM) was engaged by the Department of Defence (Defence) to undertake a quantitative human health risk assessment (HHRA) as part of the 2017 Stage 2C Environmental Investigation (2017 Stage 2C EI) at the Army Aviation Centre Oakey (AACO), in Oakey, Queensland (the Site). The HHRA forms part of Defence’s response to the detection of per- and poly-fluoroalkyl substances (PFAS) in the environment in association with the historic use of legacy aqueous film forming foam (AFFF) at the Site.

The HHRA considers both the Site and the surrounding off-Site areas, herein referred to as the Investigation Area (IA). The Site location is shown on Figure F1, Appendix A, and the IA is shown on Figure F2, Appendix A.

The 2017 Stage 2C EI principally targeted PFAS and was designed to address data gaps identified at the completion of the Stage 2C 2016 EI studies. The Stage 2C 2017 EI built upon the results of the 2015 Stage 2B EI and the 2016 Stage 2C EI.

The Site was constructed in 1943, initially as a training facility and overflow aircraft maintenance depot for RAAF Base Amberley. The Site currently operates as the Army’s helicopter training school for pilots and aviation technicians and is also home to a Republic of Singapore Airforce helicopter squadron. As part of typical airbase activities, aqueous film forming foam (AFFF) was used at the Site for fire training and emergency response from the 1970s. The main AFFF product used historically by Defence was 3M Lightwater™, which contained PFAS including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). From 2004, the Department of Defence commenced phasing out its use of legacy aqueous film forming foams (AFFF) containing PFOS and PFOA as active ingredients and progressively transitioned to a product called Ansulite for use on the Defence estate. The product currently used by Defence does not contain PFOS and PFOA as active ingredients, only in trace amounts. AECOM understands that Ansulite is used by Defence only in emergency situations where human life is at risk, or in controlled environments to test equipment, and any Ansulite used by Defence is captured and treated and/or disposed of at licensed waste disposal facilities in accordance with best practice regulations, and standards. Based on anecdotal evidence, for the purposes of this report, it has been assumed that Defence commenced phasing out the use of AFFF products containing PFOS and PFOA at the Site from 2005. This assumption has not been verified by Defence.

Previous investigations, including the 2017 Stage 2C EI and 2016 Stage 2C EI, identified the presence of PFAS on and in the vicinity of the Site in soil, groundwater, surface water, sediment, terrestrial biota and aquatic biota. Groundwater and surface water from the IA are understood to be currently (or to have been historically) used for a range of purposes, including potable water supply and domestic activities.

Previous HHRA reports prepared for the IA include the following:

AECOM 2016b. Human Health Risk Assessment, Army Aviation Centre Oakey (2016 HHRA), which:

- provided an evaluation of the potential human health risks from exposures to PFAS in the environment associated with current and ongoing use of the Site and the current land uses within the Detection Area (DA) and the IA

- included consideration of direct contact exposures to environmental media (e.g. soil, groundwater, surface water, pore water and sediment) as well as secondary exposures via dietary intakes, including fish and home grown plant and animal produce

- included specialist toxicological advice relating to PFAS, provided by ToxConsult Pty Ltd (ToxConsult), who also provided input to the preparation of the HHRA.



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AECOM 2017a. Addendum to Human Health Risk Assessment, Sensitivity Assessment of Outcomes for Food Standards Australia New Zealand Tolerable Daily Intake (2017 HHRA Addendum), which:

- assessed whether the adoption of the health based guidance values (HGBVs)1 developed in 2017 by Food Standards Australia New Zealand (FSANZ) for PFOS, PFOA and perfluorohexane sulfonate (PFHxS) would affect the conclusions of the 2016 HHRA. All other parameters remained consistent with the 2016 HHRA. The final HBGVs for PFAS were released on 3 April 2017 by the Commonwealth Department of Health (DoH). These HBGVs were developed by FSANZ at the request of DoH and replace the interim guidelines released in June 2016 by the Environmental Health Standing Committee (enHealth).

The 2016 HHRA and 2017 HHRA Addendum identified the following suggested precautions that could be followed by people living, working or undertaking recreation in the Oakey IA to minimise potential for PFAS exposure:

Do not use groundwater for drinking water supply within the IA (including water used for cooking).

Avoid or minimise use of groundwater for bathing, showering, home swimming, paddling pools and/or sprinkler play in Groundwater Zone 1 and Zone 2.

Restrict consumption of home grown eggs from backyard poultry exposed to water in Groundwater Zone 1 and Zone 2 containing detectable PFAS (i.e. PFAS reported at concentrations greater than the laboratory limit of reporting [LOR]).

Minimise consumption of the following until additional data can be collected to refine the HHRA:

- locally caught fish (entire IA)

- home grown vegetables (Groundwater Zone 1 and Zone 2)

- home grown red meat (Groundwater Zone 1 and Zone 2).

Consistent with the findings of the 2016 HHRA and 2017 HHRA Addendum, Queensland Health has published health information for the Oakey area on their website (https://www.qld.gov.au/environment/pollution/management/incidents/oakey), which currently states:

The most important thing to do for residents that live in or near a contaminated area is to reduce exposure to PFASs.

In areas where contamination of water has been identified (e.g. in underground springs, water bores, dams, ponds or creeks), human exposure can be minimised by:

Not drinking the water or using it to prepare food

Not consuming food products (e.g. eggs, milk, fish, crustaceans (prawns, yabbies/crabs), fruit or vegetables) grown or produced using, or in, contaminated water

Avoiding or minimise the use of the water for showering/bathing, sprinklers or to fill swimming pools due to the possibility of unintentionally drinking the water.

The 2016 HHRA identified a number of data gaps or uncertainties requiring further assessment. Subsequently, additional investigation works have been conducted as part of the 2017 Stage 2C EI to address these data gaps by further characterising the nature and extent of PFAS impacts and potential for human exposure to PFAS in soil, groundwater, surface water, sediment, home grown produce and seafood. This 2017 HHRA therefore provides a revised assessment of potential human health risk, incorporating additional data to address the data gaps identified in the 2016 HHRA. This 2017 HHRA also adopts the FSANZ (2017a) TDI for PFOS, PFHxS and PFOA, in accordance with the current approach endorsed in Australia for the assessment of potential risks to human health from exposure to PFAS.

1 The FSANZ HBGV released by DoH was in the form of an oral tolerable daily intake (TDI). The term TDI is used in the remainder of this report to be consistent with the Australian regulatory framework.



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Objectives of the HHRA

The objective of this HHRA is to conduct a revised assessment of potential human health risk associated with current and future exposure to PFAS in the environment within the IA, incorporating additional data to address the data gaps identified in the 2016 HHRA.

The HHRA aims to identify:

Pathways where PFAS exposure is estimated to be low and expected to be associated with no adverse health effects.

Pathways where PFAS exposure is estimated to have the potential to be elevated in comparison to the TDI, and that can be managed to most effectively reduce exposure to PFAS in the future (as recommended by Queensland Health).

HHRA Framework and Methodology

The assessment of potential human health risks associated with environmental contamination has been conducted in accordance with the National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended 2013 (ASC NEPM 2013). The HHRA has been prepared in accordance with the ASC NEPM 2013 and Environmental Health Risk Assessment, Guidelines for Assessing Human Health Risks from Environmental Hazards (enHealth, 2012a).

Conceptual Site Model

To facilitate preparation of the HHRA, a conceptual site model (CSM) was prepared based on the available information to identify the following:

a source and mechanism of chemical release

a retention or transport medium (or media where chemicals are transferred between media)

a point of potential human contact with the contaminated media

an exposure route (e.g. ingestion, inhalation) at the point of exposure.

Where a linkage between a source and receptor via a complete pathway was identified, these were assessed quantitatively in the HHRA.

The 2017 ESA (AECOM, 2017b) identified a number of activities on- and off-Site which are considered to have resulted in PFAS impacts on soil, sediment, surface water and/or groundwater. This information was used to inform investigations that have described the nature and extent of PFAS impact in the environment, which has subsequently been assessed in this HHRA.

The groups of people who may be exposed to the PFAS detected in groundwater, and who were assessed in the HHRA, were:

residents within the IA surrounding the Site

recreational users of the land and waterways within the IA surrounding the Site

commercial (agricultural) workers at the properties within the IA surrounding the Site

on-Site personnel who work at the Site (this is considered to encompass all personnel who undertake training or other operational works at the Site facility, as well as infrequent visitors).

The key exposure pathways considered in the HHRA are summarised below:

consumption of groundwater used for domestic drinking water supply and in cooking

incidental ingestion and dermal contact exposure associated with indoor domestic uses of groundwater (e.g. bathing/ showering, household cleaning, laundry)

incidental ingestion and dermal contact exposure associated with outdoor domestic uses of groundwater (e.g. swimming in pools, sprinkler play, irrigation, washing vehicles, washing animals)



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consumption of home grown plant produce (e.g. fruit, vegetables) irrigated with groundwater or surface water, grown in soil historically irrigated with groundwater or historically inundated with floodwater.

consumption of home grown animal produce (e.g. poultry eggs, red meat, milk) where animals drink groundwater or eat plants irrigated with groundwater or surface water, grown in soil historically irrigated with groundwater or historically inundated with floodwater

consumption of aquatic biota (fish and yabbies) from local waterways and future potential aquaculture farms

incidental ingestion and dermal contact exposure to surface water, sediment and/or soil associated with outdoor recreation at playing fields or local waterways (e.g. fishing, boating, swimming)

incidental ingestion and dermal contact exposure associated with commercial agriculture uses of groundwater (e.g. irrigation, washing vehicles, washing animals)

incidental ingestion, dermal contact and dust inhalation exposures associated with on-Site or off-Site activities that involve direct contact with surface soil

Exposure Assessment

Identification of the potential frequency, extent and duration of exposure to environmental media by the above groups of people via identified exposure pathways was based on information gathered from community surveys and from published data from Australian and international sources.

Human behavioural patterns vary from one individual to another. To account for this while remaining protective of general population exposures, this HHRA considers a range of exposure assumptions:

A ‘typical’ exposure was based on mean or median parameters for the general population. It is anticipated that the assessment of the typical scenario will be applicable to the majority of the population.

Upper range exposure was based on reasonable maximum exposure parameters to provide an estimate of exposure that is reflective of the upper/high end of the range of potential exposure. It is considered that the exposure frequency and quantity assumed by the upper scenario will only apply to small percentage of the population.

Representative exposure point concentrations (EPC) were identified by evaluating the available data characterising environmental media and the current understanding of the potential methods of exposure for the identified groups of people to the PFAS detected in the environment.

The EPC adopted in the HHRA for environmental media (groundwater, surface water, soil and sediment) were maximum concentrations because it was intended that the HHRA provide outcomes that could be applied to all people within each Groundwater Zone of the IA. Using the maximum concentration is likely to overestimate intakes for the average person living, working or undertaking recreation activities in the IA. The EPC adopted in the HHRA for plant and animal produce consumed by humans were the median of detected PFAS concentrations (where sufficient data were available), as these were considered most representative of long term dietary intakes for frequent consumers of those produce. Maximum concentrations were adopted for the assessment of ingestion of livestock milk, red meat and eggs due to the limited number of samples available. It is noted that the combination of upper exposure assumptions (which were based on high exposure frequency and/or high exposure quantity) and maximum concentrations as EPC is considered likely to be highly conservative.

Toxicity Assessment

A typical approach adopted in contaminated land risk assessment is to use published generic assessment criteria relevant to the land use being assessed to screen out chemicals that present a negligible risk, thereby allowing CoPC that require quantitative assessment in the HHRA to be identified. This is commonly referred to as a ‘Tier 1’ assessment.



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A Tier 1 assessment is not considered appropriate for this HHRA because PFAS have the potential to bioaccumulate within the food chain. Available Tier 1 guideline values have not been established which are protective of the potential for bioaccumulation via all potential pathways. The identification of CoPC for this HHRA was therefore based on the availability of toxicity reference values (TRV) either released by an authoritative Australian body, such as the DoH, or derived in a manner consistent with relevant Australian guidelines, for those PFAS detected above the laboratory LOR.

It is noted that there is currently no consistent evidence that exposure to the PFAS assessed in this HHRA causes adverse human health effects (FSANZ, 2017). However, because these chemicals have been shown to have health effects in animals and because these chemicals persist in humans and the environment, enHealth (2016b) recommended ‘that human exposure to these chemicals is minimised as a precaution’. The TRV adopted in this HHRA were the tolerable daily intakes (TDI) sourced from FSANZ (2017a) for PFOS, PFHxS and PFOA, and from ToxConsult (2016b) for PFHxA.

The TDI is a daily intake which, over a lifetime, is considered to be without appreciable adverse health effects, based on toxicological studies and incorporating a range of uncertainty (safety) factors. It is noted that exceeding the TDI does not necessarily mean that health effects will occur.

Risk Characterisation

The potential for adverse threshold effects resulting from exposure to an individual CoPC has been evaluated by comparing the intake for each exposure pathway, expressed as daily chemical intake, with the threshold TRV (adjusted to account for background exposure). The resulting ratio is referred to as the hazard quotient (HQ) (ASC NEPM 2013).

A potentially unacceptable chemical intake/exposure is indicated if the intake via the identified exposure pathways exceeds the TDI (i.e. if the HQ is greater than 1). To assess the overall potential for adverse health effects posed by exposure to multiple pathways, the hazard quotients for each chemical and exposure pathway relevant to a receptor are summed.

The threshold HI assumes that there is a level of exposure below which it is unlikely for humans to experience health effects, based on the available toxicological studies. If the exposure level does not exceed the threshold, i.e. if HI is equal to or less than 1, then it is reasonable to conclude that no adverse health effects are likely to be realised (ASC NEPM 2013). These low levels of exposure are considered acceptable from a health perspective because they are not likely to be associated with adverse effects, and as such, the risk estimate is referred to herein as ‘low and acceptable’.

Where risk acceptability criteria are exceeded (i.e. HI is greater than 1), the exposure is considered to be above a level which has been determined to have no adverse effects, but this does not necessarily mean that health effects will occur. In this situation, the risk estimate is referred to herein as ‘elevated’ and a more detailed and critical evaluation of the risk may be conducted, or further investigation, or appropriate exposure mitigation measures may be considered.

Summary

The following conclusions are provided with respect to the potential for PFAS exposure to identified people as a result of PFAS concentrations reported in soil, groundwater, surface water, sediment, terrestrial biota and aquatic biota within the IA.

The additional soil and groundwater data collected as part of the 2017 Stage 2C EI, combined with historical data, has allowed for the refinement of the Groundwater Zones within the IA for which the potential PFAS exposures have been assessed, as follows:

‘Groundwater Zone 2’, located immediately to the south and southwest of the Site, is inferred to have the highest magnitude of PFOS concentrations in the IA given its closer proximity to the Site, along with a potentially greater PFAS contribution from vertical migration of surface water in the vicinity of drainage channels 1 and 2.

‘Groundwater Zone 1’, located further to the south and west of the Site, is inferred to have elevated PFAS concentrations in groundwater as a result of a combination of migration mechanisms, including lateral groundwater migration and vertical migration from surface water.



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The remaining area within the IA is characterised as Groundwater Zone ‘Rest of Investigation Area’ (RoIA). The majority of the groundwater extraction wells in this zone have not reported detections of PFAS, and are located outside of Groundwater Zone 1 and Zone 2, within the boundary of the IA.

It is noted, however, that the extents of these Groundwater Zones are current as of the 2017 Stage 2C EI, and may be subject to change following the collection of additional data and/or the result of groundwater movement over time. The Groundwater Zones are presented on Figure F3, Appendix A.

The HHRA outcomes have been used to identify which aspects of the existing general advice from Queensland Health may be followed to most effectively minimise PFAS exposure in the future (https://www.qld.gov.au/environment/pollution/management/incidents/oakey). The suggested precautions on ways to minimise PFAS exposure are based on consideration of both the typical and upper range exposure scenarios assessed in the HHRA, as follows:

Where both the typical and upper range exposure scenarios are associated with elevated PFAS intakes, it is suggested that the pathway continue to be avoided.

Where only the upper range exposure scenario is associated with elevated PFAS intakes and the typical exposure scenario was identified to be associated with low and acceptable PFAS intake, it is suggested that the pathway be minimised, in order to avoid the upper range exposures assessed in this HHRA.

The estimated PFAS intakes for on-Site personnel, off-Site recreational users of publicly accessible areas (excluding consumption of fish) and off-Site commercial (agricultural) workers (excluding consumption of home grown food) were identified to be low and acceptable in comparison to the TDI. Therefore the following discussion focuses on residents in the IA, plus the food pathways mentioned above.

Groundwater Zone 2

The potential health risks to residents from exposure to PFAS through the following exposure pathways are considered to be low and acceptable:

dermal contact with groundwater as a result of indoor domestic use (excluding drinking water), outdoor domestic use (e.g. irrigation of gardens, washing animals or vehicles, playing in a sprinkler)

inhalation of dust as a result of outdoor activities or dust tracked back into the home

incidental ingestion of soil as a result of outdoor activities.

Exposure of residents to PFAS through the following exposure pathways may result in elevated PFAS intakes under scenarios considered representative of upper level and/or typical exposure:

ingestion of groundwater extracted within Groundwater Zone 2

incidental ingestion of groundwater extracted within Groundwater Zone 2 as a result of indoor use, outdoor use and irrigation, specifically:

- showering and bathing using extracted groundwater

- food preparation and clean-up

- recreational swimming in backyard swimming pools and children’s wading pools filled with extracted groundwater

- sprinkler play with extracted groundwater.

consumption of home grown leafy green vegetables irrigated with water containing detectable PFAS or grown in soil that has been irrigated with water containing detectable PFAS

consumption of home grown red meat and offal from sheep or cattle that have consumed water containing detectable PFAS and/or consumed soil or plants that have accumulated PFAS from irrigation water



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consumption of home grown milk from cattle that have consumed water containing detectable PFAS and/or consumed soil or plants that have accumulated PFAS from irrigation water

consumption of home grown eggs from backyard poultry that have consumed water containing detectable PFAS and/or consumed soil or plants that have accumulated PFAS from irrigation water.

Consistent with Queensland Health advice, it is suggested that consideration be given to the following within Groundwater Zone 2:

continue to not drink groundwater or use it in cooking

continue to not shower and/or bathe using extracted groundwater

continue to not fill swimming pools and children’s wading pools with extracted groundwater

continue to not undertake sprinkler play with extracted groundwater.

continue to not consume home grown leafy green vegetables that have been irrigated with water containing detectable PFAS or grown in soil that has been irrigated with water containing detectable PFAS

continue to not consume red meat or offal from home grown cattle or sheep located in Groundwater Zone 2 that have been exposed to water containing detectable PFAS and/or soil or plants that have accumulated PFAS from irrigation water (this precaution is also relevant to commercial agriculture workers who may consume home grown food from the property at which they work)

continue to not consume milk from home grown cattle or sheep located in Groundwater Zone 2 that have been exposed to water containing detectable PFAS and/or soil or plants that have accumulated PFAS from irrigation water

continue to not consume eggs from backyard poultry exposed to water containing detectable PFAS and/or soil or plants that have accumulated PFAS from irrigation water

minimise consumption of fish caught in Oakey Creek by people who undertake recreational fishing in this area.

Groundwater Zone 1

The potential health risks to residents from exposure to PFAS through the following exposure pathways are considered to be low and acceptable:

dermal contact with groundwater as a result of indoor domestic use (excluding drinking water), outdoor domestic use (e.g. irrigation of gardens, washing animals or vehicles, playing in a sprinkler)

inhalation of dust as a result of outdoor activities or dust tracked back into the home

incidental ingestion of soil as a result of outdoor activities

consumption of home grown milk from cattle that have consumed water containing detectable PFAS and/or consumed plants that have accumulated PFAS from irrigation water.

Exposure of residents to PFAS through the following exposure pathways may result in elevated PFAS intakes under scenarios considered representative of upper level and/or typical exposure:

ingestion of groundwater extracted within Groundwater Zone 1

incidental ingestion of groundwater extracted within Groundwater Zone 1 as a result of indoor use, outdoor use and irrigation, specifically:

- showering and bathing using extracted groundwater

- food preparation and clean-up

- recreational swimming in backyard swimming pools and children’s wading pools filled with extracted groundwater



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- sprinkler play with extracted groundwater.

consumption of home grown red meat from sheep or cattle that have consumed water containing detectable PFAS and/or consumed soil or plants that have accumulated PFAS from irrigation water

consumption of home grown leafy green vegetables irrigated with water containing detectable PFAS or grown in soil that has been irrigated with water containing detectable PFAS

consumption of home grown eggs from backyard poultry that have consumed water containing detectable PFAS and/or consumed soil or plants that have accumulated PFAS from irrigation water.

Consistent with Queensland Health advice, it is suggested that consideration be given to the following within the Groundwater Zone 1:

continue to not drink groundwater or use it in cooking

minimise showering and bathing using extracted groundwater

minimise filling swimming pools and children’s wading pools with extracted groundwater

minimise conducting sprinkler play with extracted groundwater

minimise consumption of red meat and offal from home grown cattle or sheep located in Groundwater Zone 1 that have been exposed to water containing detectable PFAS and/or soil or plants that have accumulated PFAS from irrigation water (this precaution is also relevant to commercial agriculture workers who may consume home grown food from the property at which they work)

minimise consumption of leafy green vegetables grown in areas currently or historically irrigated with water containing detectable PFAS and/or areas inundated by flooding

continue to not consume home grown eggs from backyard poultry exposed to water containing detectable PFAS and/or soil or plants that have accumulated PFAS from irrigation water

minimise consumption of fish caught in Oakey Creek by people who undertake recreational fishing in this area.

Groundwater Zone RoIA

Based on the typical exposure scenario assessed herein, the potential health risks to residents from exposure to PFAS through all the exposure pathways assessed in this HHRA are considered to be low and acceptable for all pathways combined.

Exposure of residents to PFAS through the following exposure pathways may result in elevated PFAS intakes under conservative scenarios considered representative of upper level exposure:

ingestion of groundwater extracted within Groundwater Zone RoIA

The HHRA outcome indicates that PFAS exposure via drinking groundwater would be low and acceptable under typical exposure scenarios in the Groundwater Zone RoIA. Further, the FSANZ (2017) drinking water guideline values could be used to identify specific locations where the PFAS concentrations in groundwater are acceptable for drinking. However, because Queensland Health recommends that residents that live in or near a contaminated area reduce exposure to PFAS, and because the HHRA has estimated that residents’ PFAS exposure via drinking groundwater would be greater than for all other pathways combined, it is suggested that as a precautionary measure residents continue not to use groundwater for drinking or in cooking in Groundwater Zone RoIA.

It is also suggested that people who undertake recreational fishing in this area minimise consumption of fish caught in Oakey Creek.



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Managing Future PFAS Exposure

For the purpose of communicating these outcomes and suggesting precautions for managing future PFAS exposure, Defence has adopted the following nomenclature:

Management Area: the area identified as the IA during the Stage 2C Environmental Investigation will be referred to as the Management Area. It will be divided into three Management Zones, as follows:

- Management Zone 1: the area identified as Groundwater Zone 2 for the purpose of this HHRA will be referred to as Management Zone 1.


- Management Zone 3: the area identified as Groundwater Zone RoIA for the purpose of this HHRA will be referred to as Management Zone 3.

Conclusions

The assessment undertaken within this HHRA concludes that if people living, working or undertaking recreation within the Management Area follow the existing precautionary advice from Queensland Health to minimise their intake of PFAS, they are unlikely to exceed the TDI. Conversely, it is concluded that unrestricted exposure to PFAS across the Management Area is likely to result in an exceedance of the TDI.

The HHRA conclusions are summarised in Table ES1 for residents, Table ES2 for commercial agriculture workers, Table ES3 for recreational users of publicly accessible areas and Table ES4 for on-Site personnel.

These conclusions are based on consideration of the theoretical scenarios identified in the HHRA that could be associated with elevated PFAS intakes, the data gaps and uncertainties inherent in these assessments, and that PFAS concentrations measured in the blood of Oakey residents are elevated above typical background concentrations for people in Australia.

These conclusions should be read in conjunction with the data gaps presented in Section 4.2.4 and sensitivity assessment presented in Section 8.3.



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Table ES1 Summary of HHRA Conclusions for Residents

Exposure Pathway

Potential PFAS Exposures –

Management Zone 1


Management Zone 2


Management Zone 3 Suggested Precautions to Minimise Future PFAS Exposure

Upper Typical Upper Typical Upper Typical

Groundwater

Drinking groundwater or using it in cooking

Elevated Elevated Elevated Elevated Elevated Low & Acceptable

Management Zone 1 and Zone 2: Continue to follow Queensland Health advice to not drink groundwater or use it in cooking.

Management Zone 3: Because Queensland Health recommends that residents that live in or near a contaminated area reduce exposure to PFAS, and because the HHRA has estimated that residents’ PFAS exposure via drinking groundwater would be greater than for all other pathways combined, it is suggested that as a precautionary measure residents continue not to use groundwater for drinking or in cooking in Management Zone 3.

Incidental ingestion of groundwater as a result of indoor domestic use (excluding drinking water) and outdoor domestic use

Elevated Elevated Elevated Low & Acceptable

Low & Acceptable

Low & Acceptable

Management Zone 1: Continue to follow Queensland Health advice to avoid the use of groundwater for: showering and bathing; filling swimming pools and children’s wading pools; and sprinkler play.

Management Zone 2: Continue to follow Queensland Health advice to minimise the use of groundwater for: showering and bathing; filling swimming pools and children’s wading pools; and sprinkler play.

Management Zone 3: No precaution suggested



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Exposure Pathway


Management Zone 1


Management Zone 2




Dermal contact with groundwater as a result of indoor domestic use (excluding drinking water) and outdoor domestic use

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

No precaution suggested

Soil

Incidental ingestion of soil as a result of outdoor activities

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Dermal contact with soil as a result of outdoor activities

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities or dust tracked back into the home

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable




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Exposure Pathway


Management Zone 1


Management Zone 2




Locally sourced food

Consumption of vegetables that have been irrigated with water containing detectable PFAS, or have been grown in soil that has been irrigated or flooded with water containing detectable PFAS


Low & Acceptable

Low & Acceptable

Management Zone 1: Continue to follow Queensland Health advice to avoid consumption of home grown leafy green vegetables that have been irrigated with water containing detectable PFAS, or have been grown in soil that has been irrigated or flooded with water containing detectable PFAS.

Management Zone 2: Minimise consumption of home grown leafy green vegetables that have been irrigated with water containing detectable PFAS, or have been grown in soil that has been irrigated or flooded with water containing detectable PFAS.




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Exposure Pathway


Management Zone 1


Management Zone 2




Consumption of red meat or offal from sheep or cattle that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS


Low & Acceptable

Low & Acceptable

Management Zone 1: Continue to follow Queensland Health advice to avoid consumption of red meat and offal from home grown cattle or sheep that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS.

Management Zone 2: Minimise consumption of red meat and offal from home grown cattle or sheep that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS.


Consumption of milk from livestock that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS

Elevated Elevated Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Management Zone 1: Continue to follow Queensland Health advice to avoid consumption of milk from home grown cattle or sheep that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS.

Management Zone 2 and Zone 3: No precaution suggested



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Exposure Pathway


Management Zone 1


Management Zone 2




Consumption of eggs from backyard poultry that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS

Elevated Elevated Elevated Elevated Low & Acceptable

Low & Acceptable

Management Zone 1 and Zone 2: Continue to follow Queensland Health advice to avoid consumption of eggs from backyard poultry that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS.


Under circumstances where exposure of backyard chickens to media containing detectable PFAS can be prevented Scolexia (2017) estimated that a withholding period of 100 days after cessation of PFAS exposure to hens would likely be required for all four PFAS studied to reduce to less than the laboratory LOR in eggs from backyard poultry in the Management Area.



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Table ES2 Summary of HHRA Conclusions for Commercial Agriculture Workers

Exposure Pathway


Management Zone 1


Management Zone 2




Groundwater

Incidental ingestion of groundwater as a result of outdoor commercial agriculture use

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Dermal contact with groundwater as a result of outdoor commercial agriculture use

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Soil


Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable



Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable




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Exposure Pathway


Management Zone 1


Management Zone 2





Consumption of red meat and offal from sheep or cattle that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS


Low & Acceptable

Low & Acceptable





Not a Complete Pathway




Low & Acceptable

Low & Acceptable




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Table ES3 Summary of HHRA Conclusions for Recreational users of publicly accessible areas

Exposure Pathway

Potential PFAS Exposures – Entire Management Area Suggested Precautions to Minimise Future PFAS Exposure

Upper Typical

Surface Water

Incidental ingestion of surface water as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Dermal contact with surface water as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Soil and Sediment

Incidental ingestion of soil and sediment as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Dermal contact with soil and sediment as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities Low & Acceptable

Low & Acceptable



Consumption of fish from local waterways by recreational fishers

Elevated Low & Acceptable

Minimise consumption of fish from Oakey Creek.

Consumption of fish sourced from future aquaculture systems where groundwater or surface water containing detectable PFAS is used to supply the system

Elevated Elevated The potential risk to human health should be further evaluated based on Site-specific data prior to undertaking aquaculture in the Management Area using groundwater or surface water containing detectable PFAS in the future.



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TableES4 Summary of HHRA Conclusions for On-Site Personnel

Exposure Pathway

Potential PFAS Exposures – On-Site Suggested Precautions to Minimise Future PFAS Exposure

Upper Typical

Soil


Low & Acceptable

Low & Acceptable



Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities or dust tracked back into the workplace

Low & Acceptable

Low & Acceptable




1

1.0 Introduction

1.1 This Report

AECOM Australia Pty Ltd (AECOM) was engaged by the Department of Defence (Defence) to undertake a quantitative human health risk assessment (HHRA) as part of the 2017 Stage 2C Environmental Investigation (2017 Stage 2C EI) at the Army Aviation Centre Oakey (AACO), in Oakey, Queensland (the Site). The HHRA forms part of Defence’s response to the detection of per- and poly-fluoroalkyl substances (PFAS) in the environment in association with the historic use of aqueous film forming foam (AFFF) at the Site.

AECOM has completed the 2017 Stage 2C EI to inform the HHRA. The 2017 Stage 2C EI principally targeted PFAS and was designed to address data gaps identified at the completion of the 2016 Stage 2C EI studies. The 2017 Stage 2C EI built upon the results of the 2015 Stage 2B EI and the 2016 Stage 2C EI.

The HHRA considers both the Site and the surrounding off-Site areas, herein referred to as the Investigation Area (IA), as discussed in Section 1.3. The Site location is shown on Figure F1, Appendix A, and the IA is shown on Figure F2, Appendix A.

This HHRA forms part of an overarching Stage 2C Environmental Investigation, which applies a staged approach to the evaluation of potential risk associated with identified PFAS impacts in the environment on and surrounding the Site. The components of the current stage of environmental investigation are summarised below:

AECOM, 2016a. Environmental Site Assessment (ESA), Army Aviation Centre Oakey (2016 ESA), which aimed to:

- build on previously collected data (described in Section 1.2) to provide a better understanding of the distribution of PFAS in soil, groundwater, surface water and sediment in the IA

- improve the understanding of the hydrogeology and surface hydrology characteristics of the IA, develop a better understanding of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) movement pathways and temporal variations, and model the historical and future movement of PFOS and PFOA in groundwater

- develop a numerical model (undertaken by Australasian Groundwater and Environmental Consultants Pty Ltd, AGE) to simulate groundwater flow and solute transport (migration of PFOS and PFOA in groundwater)

- refine the conceptual site model (CSM) by integrating the findings of the ESA with existing data to describe the PFAS sources, pathways and potentially exposed people

- generate data to assist with the future development of management options for PFAS impacts.

AECOM, 2016b. Human Health Risk Assessment, Army Aviation Centre Oakey (2016 HHRA), which:

- provided an evaluation of the potential human health risks from exposures to PFAS in the environment associated with current and ongoing use of the Site and the current land uses within the Detection Area (DA) (defined in Section 1.2 below) and the IA

- included consideration of direct contact exposures to environmental media (e.g. soil, groundwater, surface water, pore water and sediment) as well as secondary exposures via dietary intakes, including fish and home grown plant and animal produce

- included specialist toxicological advice relating to PFAS, provided by ToxConsult Pty Ltd (ToxConsult), who also provided input to the preparation of the HHRA.



2

AECOM, 2016c. Preliminary Ecological Risk Assessment (ERA), Army Aviation Centre Oakey, which assessed:

- the potential risk from the identified PFAS detections in the IA to ecological receptors which inhabit the Site and surrounding off-Site areas within the IA

- the potential for PFAS impacts to result in bioaccumulation and biomagnification in terrestrial and aquatic organisms exposed to Site-derived PFAS

- the potential for wider ecosystem impacts to result from the bioaccumulation of PFAS in terrestrial and aquatic organisms exposed to Site-derived PFAS.

AECOM, 2017a. Addendum to Human Health Risk Assessment, Sensitivity Assessment of Outcomes for Food Standards Australia New Zealand Tolerable Daily Intake (2017 HHRA Addendum), which:

- assessed whether the adoption of the health based guidance values (HGBV)2 developed in 2017 by Food Standards Australia New Zealand (FSANZ) for PFOS, PFOA and perfluorohexane sulfonate (PFHxS) would affect the conclusions of the 2016 HHRA. All other parameters remained consistent with the 2016 HHRA. The final Health Based Guidance Values (HBGVs) for PFAS were released on 3 April 2017 by the Commonwealth Department of Health (DoH). These HBGVs were developed by FSANZ at the request of DoH and replace the interim guidelines released in June 2016 by the Environmental Health Standing Committee (enHealth).

AECOM, 2017b. Environmental Site Assessment (ESA), Army Aviation Centre Oakey (2017 ESA), which:

- included conducting data gap investigations and analysis to update the 2016 ESA. The purpose of the data gap analysis was to reduce uncertainty about the nature and extent of PFAS impact in relation to some of the risk exposure pathways and magnitudes, and to refine assumptions used to assess risks to human health and ecological receptors. By addressing the data gaps, the ESA enabled the following:

refinement of the conceptual site model and groundwater models (flow and solute transport)

improved understanding of the current groundwater conditions with respect to non-PFAS CoPC in groundwater that may impact PFAS remediation options

improved understanding of the presence and distribution of the extended suite of PFAS by analysing sample media (soil, sediment, surface water and groundwater) for the full PFAS suite

collation of a data set to inform future environmental sampling requirements to be used as a basis for the Ongoing Monitoring Plan (OMP) (the development of the OMP itself is a separate project component)

improved understanding of the influence of stormwater drains on PFAS migration through completion of leachate and infiltration tests. This includes understanding the distribution of PFAS in sediments and near-surface soils at locations along drainage lines

improved understanding of the temporal variability of PFAS in surface water in drainage channels

improved understanding of source areas on-Site

2 The FSANZ HBGV released by DoH was in the form of an oral tolerable daily intake (TDI). The term TDI is used in the remainder of this report to be consistent with the Australian regulatory framework.



3

improved understanding of the lateral extent and indicative distribution of PFAS contamination in groundwater. This information has been used in the 2017 HHRA to better refine the extent and boundaries of Groundwater Zone 1 and Zone 2 as previously identified in the 2016 HHRA

improved understanding of the movement of PFAS into the underlying alluvial aquifer and the potential contaminant migration from the Oakey Creek Alluvium to the underlying Great Artesian Basin (GAB) and basalt aquifers

improved understanding of the groundwater resources associated with the underlying Walloon Coal Measures, which form part of the hydrogeological GAB, and the Main Range Volcanics aquifers

improved understanding of the water interactions, the influence of flooding, surface water extraction and irrigation return on PFAS migration/extent, and the correlation between concentrations in irrigation water and soil.

AECOM, 2017c. Human Health Risk Assessment, Army Aviation Centre Oakey (2017 HHRA) – this report, which:

- updates the 2016 HHRA using additional data collected as part of the 2017 Stage 2C EI to address data gaps identified in the 2016 HHRA. The 2017 HHRA also includes consideration of identified potential exposure pathways that are not currently complete, but have the potential to be complete in the future (i.e. consumption of fish from aquaculture systems).

- adopts the FSANZ (2017a) TDI for PFOS, PFHxS and PFOA, in accordance with the current approach endorsed in Australia for the assessment of potential risks to human health from exposure to PFAS.

AECOM, 2017d Ecological Risk Assessment, Army Aviation Centre Oakey (2017 ERA) in preparation, which:

- assesses the potential risk from the identified PFAS impacts on ecological receptors that inhabit habitats present at the Site and surrounding area using additional data collected for the ERA

- assesses the potential for wider ecosystem impacts to result from the accumulation of PFAS in terrestrial and aquatic organisms exposed to PFAS impacts

- updates the assumptions previously adopted in the Preliminary Ecological Risk Assessment based on additional data collected in 2017 for the ERA.

1.2 Background

Fire-fighting training and emergency response services involving the use of AFFF containing PFAS have occurred at the Site since the 1970s. AFFF products are fire suppressing foams that have been used at the Site for fire-fighting training activities and emergency response for approximately 40 years. The main AFFF product used historically by Defence was 3M Lightwater™, which contains PFAS including PFOS and PFOA. From 2004, the Department of Defence commenced phasing out its use of legacy aqueous film forming foams (AFFF) containing PFOS and PFOA as active ingredients and progressively transitioned to a product called Ansulite for use on the Defence estate. The product currently used by Defence does not contain PFOS and PFOA as active ingredients, only in trace amounts. AECOM understands that Ansulite is used by Defence only in emergency situations where human life is at risk, or in controlled environments to test equipment, and any Ansulite used by Defence is captured and treated and/or disposed of at licensed waste disposal facilities in accordance with best practice regulations, and standards. Based on anecdotal evidence, for the purposes of this report, it has been assumed that Defence commenced phasing out the use of AFFF products containing PFOS and PFOA at the Site from 2005. This assumption has not been verified by Defence (AECOM, 2016b).

AECOM has conducted various investigations at the Site since November 2013 to facilitate Defence’s long term objective of identifying and managing potential risks associated with PFAS contamination. The IA is described as the broader area, including the Site and surrounds, which is being studied as



4

part of assessing the extent of PFAS detections in the groundwater. The boundaries of the IA have changed over time as more information has become available. Currently the IA encompasses the majority of the Site and includes a buffer area beyond the known extent of PFOS and PFOA detected in groundwater (referred to as the Detection Area) and extends approximately 5.5 km south and 3.5 km west of the Site (refer to Section 1.3).

The data from these previous investigations included:

on-Site:

- groundwater samples from groundwater monitoring wells

- soil samples

- surface water and sediment samples from drainage channels

- plant tissue (from an on-Site area leased for agricultural purposes)

- rabbit muscle tissue (from wild animals collected following a routine cull).

off-Site:

- groundwater samples from groundwater monitoring wells and private extraction bores

- surface water and sediment samples from drainage channels and natural waterways

- surface water samples from private dams

- groundwater or surface water samples used for irrigation purposes

- soil samples from properties where groundwater or surface water has been used for irrigation purposes, or surface water flooding has historically occurred

- plant tissue samples (from properties where groundwater containing PFAS had been used for irrigation purposes)

- backyard chicken eggs, livestock blood serum and livestock milk samples (from properties where groundwater containing PFAS had been used for stock watering purposes)

- fish tissue samples.

The data from these previous investigations was reported in the 2016 HHRA. The 2016 HHRA report identified a number of data gaps or uncertainties requiring further assessment. The key data gaps identified in the 2016 HHRA are summarised below in Table 1 and form the basis of the scope for this phase of assessment.

Sampling conducted in 2017 to address the data gaps reported in the 2016 HHRA included:

on-Site:

- groundwater samples from 52 groundwater monitoring wells (10 newly installed and 42 existing wells)

- soil samples from 31 soil bores and 10 monitoring wells

- sediment samples from 21 bores advanced along drainage channels

- a total of 22 stormwater samples from drainage channels.

off-Site:

- groundwater samples from 30 newly installed wells and 37 existing Defence-owned monitoring wells

- a total of 102 primary soil samples from the newly installed wells

- sediment samples from the 13 bores advanced along the drainage channels off-Site

- a total of 11 surface water samples from drainage channels

- surface water and sediment samples collected from Oakey Creek, Doctor Creek and Westbrook Creek



5

- groundwater samples from 81 residential groundwater extraction bores

- collection of additional fruit and vegetable samples co-located with soil and groundwater samples (from properties where groundwater containing PFAS had been used for irrigation purposes or had been inundated with floodwater historically)

- collection of additional backyard chicken eggs, duck eggs and goose eggs (from properties where groundwater containing PFAS had been used for irrigation or stock watering purposes, or had been historically inundated with floodwater)

- fish, yabbies and mussels from Oakey Creek, Doctor Creek and Westbrook Creek.

All samples were analysed for an extended suite of PFAS (refer to the List of Acronyms at the start of this report for the extended PFAS suite analysed by each laboratory).

Table 1 Data Gaps Identified in 2016 HHRA

Data Gap Addressed in this Report

Relevant Section

The 2016 HHRA was based on biota (i.e. plants and animals used for human consumption) data collected during an initial sampling event that was targeted to potential areas of greater PFAS impact. As a result, typical exposure may be overestimated in the HHRA and additional data are required to address this uncertainty. Additionally, other home grown produce may be present in the DA which was not sampled as part of the 2016 HHRA.

Yes

Additional data were collected to characterise PFAS concentrations in fruit, vegetables, backyard chicken, duck and goose eggs, yabbies and mussels grown within the IA and used for human consumption (refer to Section 4.4). The duck and goose eggs were noted to have similar magnitude PFAS concentrations to the chicken eggs, and therefore the assessment of chicken egg consumption in the HHRA is also considered representative of potential for PFAS intakes from consumption of these other types of poultry eggs. The additional biota data collected have been used to update the exposure point concentrations (EPC) and refine the HHRA (refer to Section 5.5). Sampling locations were selected based on a community survey that aimed to obtain more information about fruit, vegetables, aquatic fauna (fish, mussels and yabbies), and backyard chicken eggs grown within the IA, and potentially exposed to PFAS, that residents may consume on a regular basis. The survey responses were used to update the human exposure assumptions and refine the HHRA (refer to Section 5.1.2).

No chicken egg samples were collected within Groundwater Zone 1. Chicken eggs sampled at a single property within Groundwater Zone 2 were considered to provide data representative of upper range PFAS concentrations in groundwater consumed by the chickens (refer to Table 2 for definitions of Groundwater Zone 1 and Zone 2).

Yes The results of additional egg sampling from the IA (refer to Section 4.4) have been supplemented by a study undertaken to evaluate PFAS residues (at or near steady state) in chicken eggs from birds exposed to a range of PFAS concentrations via drinking water (refer to Appendix L). The data collected have been used to estimate theoretical EPC for egg consumption and refine the HHRA.



6

Data Gap Addressed in this Report

Relevant Section

The 2016 HHRA assessed potential human exposure via consumption of locally caught fish, but no data were available to evaluate potential exposure via consumption of other aquatic fauna such as yabbies or freshwater mussels.

Yes Additional aquatic biota sampling was conducted to further assess the potential range of PFAS concentrations that may be encountered in the edible portion of aquatic fauna (specifically, yabbies and freshwater mussels) that may be collected from publicly accessible waterways in the IA (refer to Section 4.4). The additional biota data collected were used to update the CSM (Section 4.8) and EPC, and to refine the HHRA (refer to Section 5.5).

Low frequency of analysis of the extended suite of PFAS, including PFHxS and perfluorohexanoic acid (PFHxA), in environmental media at the initial time of analysis.

Yes All groundwater, soil, surface water, sediment and biota samples collected in 2017 were analysed for the extended suite of PFAS including PFHxS and PFHxA (refer to Section 4.4). The additional data collected was used to update the EPC and refine the HHRA.

Limited responses to community surveys Yes An additional community survey was undertaken to obtain more information about how people in the IA would typically use their land to grow plant produce and livestock, together with quantities consumed and typical frequency. The survey responses were used to update the human exposure assumptions and refine the HHRA (refer to Section 5.1.2 and Appendix E).

The majority of private bores do not have construction details available; therefore, the screened depth and targeted aquifer cannot be verified at all locations.

Yes Approximately 30 additional groundwater monitoring bores (nine on-Site and 21 off-Site) were advanced in the shallow groundwater to provide a better understanding of the distribution of PFAS in the groundwater of the Oakey Creek Alluvium aquifer (refer to Section 4.3.1). The additional data collected was used to update the CSM and EPC to refine the HHRA.

Potential future land uses not currently occurring (e.g. aquaculture) were not assessed. No private aquaculture systems are understood to be present in the IA.

Yes The potential consumption of fish raised in future aquaculture systems was assessed via an assumption that groundwater or surface water in the IA could be used in aquaculture systems (refer to Section 8.2).



7

1.3 Investigation Area Definition

The key features of the Stage 2C IA as defined in the 2016 HHRA, compared with this report, are provided in Table 2.

Table 2 Stage 2C Investigation Area features

Key Zones As defined in 2016 HHRA As defined in 2017 HHRA

Investigation Area (IA)

The IA is the broader area including the Site and surrounds which is being studied as part of assessing the extent of PFAS detections in the groundwater. In 2016 the IA encompassed the majority of the Site and included a buffer area beyond the known extent of PFOS and PFOA detected in groundwater (referred to as the DA) and extended approximately 5.5 km south and 3.5 km west of the Site.

The boundaries of the IA have not changed in 2017. Refer to Figure F2, Appendix A.

Detection Area (DA)

The DA is defined by locations within the IA at which PFOS and PFOA have been detected in groundwater samples above the laboratory limit of reporting (LOR). In 2016 the extent of the DA encompassed the south-western portion of the Site and extended approximately 4.5 km south, to the confluence of Oakey Creek and Westbrook Creek, and 2.5 km west of the Site. Two PFAS detection zones (Groundwater Zone 1 and Zone 2) were identified in the DA.

The boundaries of the DA have changed over time as more information has become available. Within this revised HHRA, three PFAS detection zones have been identified in the IA, as described below (refer to Section 4.3.2 and Figure F2, Appendix A).

Groundwater Zone 1

Groundwater Zone 1 was defined in the 2016 HHRA to encompass the south and west of the Site, and covered the majority of the DA, in which PFAS impacts on groundwater are inferred to have resulted from a combination of migration mechanisms including lateral groundwater migration and vertical migration from surface water.

The increased density of sampling locations and temporal data gathered as part of the Stage 2C 2017 EI, together with historical investigations, have allowed for further refinement of Groundwater Zone 1 and Zone 2, and the addition of the third zone (Rest of Investigation Area [RoIA]) (refer to Section 4.3.2).

Groundwater Zone 2

Groundwater Zone 2 was defined in the 2016 HHRA to encompass the area immediately to the south of the Site, which was inferred to have greater magnitude PFOS concentrations than Groundwater Zone 1 owing to closer proximity to the Site, along with a potentially greater PFAS contribution from vertical migration of surface water in the vicinity of drainage channel 1 and drainage channel 2.

Groundwater Zone ‘Rest of Investigation Area’ (RoIA)

Not defined in 2016 HHRA.



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1.4 Objective

The objective of the 2017 HHRA is to conduct a revised assessment of potential human health risk associated with current and future exposure to PFAS in the environment within the IA, incorporating additional data to address the data gaps identified in the 2016 HHRA.

The HHRA aims to identify:

pathways where PFAS exposure is estimated to be low and expected to be associated with no adverse health effects

pathways where PFAS exposure is estimated to have the potential to be elevated in comparison to the TDI, and that can be managed to most effectively reduce exposure to PFAS in the future (as recommended by Queensland Health).

1.5 Framework and Methodology

Consistent with the Environmental Protection Act 1994 (Qld), this assessment has been conducted based on the framework outlined in the National Environment Protection (Assessment of Site Contamination) Measure 1999 (as amended 2013) [ASC NEPM 2013].

The HHRA has also been prepared with reference to methodology outlined in the following relevant nationally adopted guidance:

Environmental Health Risk Assessment, Guidelines for Assessing Human Health Risks from Environmental Hazards. Department of Health and Aging, 2012 Update (enHealth, 2012b)

National Environment Protection (Assessment of Site Contamination) Measure 1999 (as amended 2013) [ASC NEPM 2013], specifically:

- Schedule B4 Guideline on Site-Specific Health Risk Assessment Methodology

- Schedule B7 Guideline on Derivation of Health-Based Investigation Levels.

The HHRA framework is illustrated on Figure 1.



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Figure 1 HHRA framework for contaminated sites (Source: ASC NEPM 2013)

Issues Identification

Why are we doing this assessment? Is a risk assessment the right type of

decision-making tool? Who and what are stakeholder

objectives? What are we trying to find out? What are the sources and hazards? What exposure pathways should be

investigated? What decisions need to be made and

when (urgency of answers)? Problem formulation

Health Risk Assessment Environmental Site Assessment

Preliminary conceptual site model

Data collection and evaluation

Collection and analysis of relevant site data

Development of conceptual site model Evaluate uncertainties

Working conceptual site model

Other assessments

(e.g. ecological, groundwater, geotechnical)

Toxicity assessment

Review qualitative and quantitative toxicity information (relevant to reference values)

Determine appropriate dose-response relationships

Identify most appropriate quantitative toxicity reference values

Evaluate uncertainties

Exposure assessment

Analysis of contaminant releases

Identification of potential exposure pathways

Estimation of exposure concentrations for each pathway

Estimation of contaminant intake for each pathway

Evaluate uncertainties

Risk characterisation

Characterise potential for adverse health effects to occur

Evaluate uncertainty Undertake sensitivity analysis Summarise risk information

and evaluation

Risk communication and management

Refined conceptual site model

Engage with stakeholders, risk communication and community engagement



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1.6 Scope of Work

The scope of work for this HHRA is presented in Section 1.6.1 to Section 1.6.5. The structure of this HHRA generally reflects the staged risk assessment approach summarised in Figure 1.

1.6.1 Step 1: Issues Identification

Issues identification is the process of planning and scoping the risk assessment and problem formulation. Information presented at this stage of the HHRA includes:

description of the rationale for undertaking the HHRA

identification of stakeholders relevant to the HHRA and its outcomes

outline of the HHRA objectives

discussion of how the HHRA outcomes are relevant to subsequent risk management decisions.

Issues identification is presented in Section 3.0 of this report.

1.6.2 Step 2: Data Collection, Evaluation and Conceptual Site Model

Data evaluation is the process of reviewing the available data set and determining whether it is appropriate for use in the risk assessment. This is followed by a description of the CSM and identification of the chemicals of potential concern (CoPC) to be evaluated in the quantitative assessment. Information presented at this stage of the HHRA includes:

review of the relevant available information relating to previous investigations within the IA

assessment of the quality and quantity of data available for use in this HHRA

identification of CoPC for the quantitative HHRA

assessment of the data gaps associated with environmental investigations completed in the IA to date, and their significance with respect to this HHRA

identification of any rationale for Site zoning or statistical considerations when evaluating the data

description of the CSM, which identifies the following:

- the source(s) of PFAS

- potential PFAS transport mechanisms and/or migration pathways

- potential people that may be exposed to PFAS in the environment via potentially complete exposure pathways.

Data collection, evaluation and a description of the CSM are presented in Section 4.0 of this report. As this report presents an update of a previous HHRA, Section 4.0 of the report is primarily focused on the works undertaken during 2017 to address previously identified data gaps.

A typical approach adopted in contaminated land risk assessment is to use published generic assessment criteria relevant to the land use(s) being assessed to screen out chemicals that present a negligible risk, thereby allowing CoPC that require quantitative assessment in the HHRA to be identified. This is commonly referred to as a ‘Tier 1’ assessment.

A Tier 1 assessment is not considered appropriate for this HHRA because PFAS have the potential to bioaccumulate within the food chain. Available Tier 1 guideline values have not been established which are protective of the potential for bioaccumulation via all potential pathways. The identification of CoPC for this HHRA was therefore based on the availability of toxicity reference values (TRV) derived in a manner consistent with relevant Australian guidelines, for those PFAS detected above the laboratory LOR.



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1.6.3 Step 3: Exposure Assessment

Exposure assessment is the process of estimating the magnitude, frequency, extent and duration of human exposure to PFAS and refinement of the CSM based on these considerations. Specifically, this stage includes:

translation of the CSM into modelling terms and further refinement of the CSM (if necessary)

identification and justification of the expected frequency, extent and duration of exposure to environmental media by people via identified exposure pathways. Exposure parameters were adopted with consideration of information gathered from community surveys, field observations and from published data from Australian and international sources

identification of representative EPC in environmental media that were used in the HHRA. Representative EPC were identified by evaluating the available data characterising environmental media and the current understanding of how the identified people might be exposed to the PFAS detected in the environment

quantitative estimation of chemical intakes for people via the identified potentially complete exposure pathways.

Exposure assessment is presented in Section 5.0 of this report.

1.6.4 Step 4: Toxicity Assessment

Toxicity assessment is the process of understanding the health effects associated with exposure to PFAS and making a quantitative link between the degree of exposure and the effect that could be realised. Specifically, this stage of the HHRA includes:

qualitative review of the potential hazards to human health associated with each CoPC

review of toxicological (dose-response) criteria for each CoPC and identification of appropriate quantitative toxicity criteria to use in the HHRA.

Toxicity assessment is presented in Section 6.0 of this report.

1.6.5 Step 5: Risk Characterisation

Risk characterisation is the process of summarising information from the previous steps and integrating it into a quantitative expression of potential risk. Specifically, this stage includes:

characterisation of the nature and potential incidence of adverse health effects on people based on comparison of estimated contaminant intake or exposures to relevant TRV

comparison of risk estimates against risk acceptance criteria recommended and/or adopted by state and federal regulatory agencies

discussion of the key uncertainties associated with the HHRA process and the assumptions and exposure modelling undertaken for the HHRA

sensitivity assessment and consideration of the risk estimates in the context of the identified uncertainties.

Risk characterisation is presented in Section 7.0 of this report. The uncertainty evaluation and sensitivity assessment is presented in Section 8.0 of this report.



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2.0 Site Identification and Environmental Setting

2.1 Site Location and Surrounding Land Use

2.1.1 Regional Oakey District

In a regional context, the Site is located approximately 35 km north-west of Toowoomba on the western side of the Great Dividing Range, as shown on Figure F1, Appendix A. Oakey is located within the Darling Downs region, approximately 128 km west of Brisbane. Current land uses surrounding the Site are largely residential and ruralresidential, with some agricultural land use. The major land uses in the region are agriculture, cattle grazing and horse agistment. In Oakey the land uses include low density residential, commercial premises and industrial properties. The closest urban uses to the Site are a series of industrial properties located on Orr Road, approximately 800 m to the south of the Site.

2.1.2 The Site

The Site occupies an area of approximately 850 hectares and is located on alluvial floodplains approximately 2 km north-east of Oakey. The Site is currently used by the Defence Force for Army Aviation, and has maintained a role as a military facility since the Site’s inception in 1943. The Site boundary is shown on Figure F2, Appendix A, along with major Site features. The northern part of the Site is the airfield, while the southern part of the Site comprises support services, buildings and infrastructure. Approximately 290 hectares of the Site are leased for agriculture (to the west of the active portion of the Site). The Site is bounded by Corfe Road, Oakey Cooyar Road, Wilthorne Kelvinhaugh Road and Oakey Kelvinhaugh Road. The main access point to the Site is via Beale Street and Orr Road. The Warrego Highway and Western Railway Line are located approximately 3 km and 1 km to the south of the Site, respectively.

2.1.3 Land Use

A summary of the main land uses surrounding the Site is provided in Table 3.

Table 3 Summary of land use surrounding the Site

Direction Land use

North Rural allotments utilised for a range of pastoral and agricultural purposes (principally for grain cropping and livestock production).

South Immediately to the south of the Site are rural-residential allotments

Immediately south-west of the Site are residential allotments and the Oakey Racecourse

The township of Oakey is located approximately 2 km to the south of the site and comprises residential, light industrial and business/commercial zoned areas.

East Rural allotments utilised for a range of pastoral and agricultural purposes (principally for grain cropping and livestock production).

West Rural allotments utilised for a range of pastoral and agricultural purposes (principally for grain cropping and livestock production).

2.2 Topography

The Site is located on a relatively flat alluvial plain. The regional topography slopes to the west and south-west in the direction of the Oakey and Condamine River Floodplains. The locations of the Site, Oakey Creek and Doctor Creek are shown on Figure F2, Appendix A. The elevation of the Site is approximately 400 m AHD. Locally, inclines have been constructed to grade the drainage system away from the runways. The Site drains to the south via a series of unlined drains discharging into Oakey Creek.



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Cooby Creek Reservoir is located approximately 20 kilometres to the north-east of the Site (refer to Figure F1, Appendix A), in the headwaters of the Oakey Creek catchment, which partially regulates flow in Oakey Creek.

The physiography and drainage patterns of the Oakey Creek catchment have been outlined by Murphy (1990) and categorised as follows:

1. The dissected basaltic uplands in the upper part of the catchment are composed of the Main Range Volcanics and Marburg Formations that are still undergoing down cutting and erosion.

2. Basaltic plateau, also located in the uplands, with more subdued relief that is undergoing limited erosion and weathering due to the low relief.

3. Mature landscapes lower in the catchment with undulating relief, where the bedrock has been modified by erosion.

4. The alluvial plains flanking Oakey Creek, and terraces and colluvial slopes composed of the weathered bedrock.

2.3 Climate

The average annual rainfall for Oakey between 1970 and 2015 was 633 mm3. The wettest months occur during summer with relatively dry winter months.

Long term Oakey SILO data sets (1970 to 2015) indicate average evaporation peaks at 216 mm/month in December and January and is lowest at 69.2 mm/month in June.

Potential evapotranspiration peaks at 170 mm/month in December and is lowest at 56.3 mm/month in June.

The higher evaporation compared to rainfall indicates a negative climate balance across the Oakey area.

2.4 Geology

Tectonically, the Site and surrounds are situated within the central eastern part of the Clarence-Moreton Basin, which contains sediments of the Late Triassic to Later Jurassic age. The Walloon Coal Measures is the uppermost formation of the Clarence-Morton Basin, which underlies the IA. Unconformably overlying the Clarence-Moreton Basin are extensive areas of consolidated younger alluvial sediments, such as Oakey Creek Alluvium and Main Range Volcanics. Table 4 indicates the geological stratigraphy in the IA.

Table 4 Stratigraphy (source: AGE, 2016)

Period Unit Lithology Geological basin

Hydrogeological basin

Cenozoic

(Quaternary)

Oakey Creek Alluvium

Gravel, sand, silt and clay Clarence-Moreton Basin

Great Artesian Basin

Cenozoic (Tertiary)

Main Range Volcanics

Alkali-olivine basalt, minor tuff, sandstone and mudstone

Mesozoic (Jurassic)

Walloon Coal Measures

Thin-bedded, claystone, shale, siltstone, lithic and sublithic to feldspathic arenites, coal seams and partings, and minor limestone

3 Based on the Bureau of Meteorology’s Oakey Aero station #41359 data set, and the Oakey scientific information for land owners (SILO) rainfall data set.



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The Oakey Creek Alluvium is deposited in valleys formed on weathered Palaeozoic, Mesozoic and Tertiary bedrock (Barnett and Muller, 2008). The alluvium and alluvial deposits are heterogeneous floodplain and sheet wash deposits. Floodplain deposits are coarse grained sands and gravels located towards the centre of the river channel. Sheet wash deposits are finer grained and surround the floodplain deposit and extend out towards the alluvial valley margins.

The Oakey Creek Alluvium is flanked by Tertiary aged colluvium and basalt (GSQ, 1980). The colluvium consists of cemented scree deposits and rock debris that overlie the Cenozoic-aged Main Range Volcanics (basalt) which crop out approximately 1.9 km south-east of the Site.

The Jurassic-aged Walloon Coal Measures also crop out in the area and are composed of shale, siltstone, sandstone, coal, mudstone and limestone. North-west of Oakey, the Walloon Coal Measures and the Main Range Volcanics crop out in the upper reaches of Oakey Creek. The Marburg Formation is part of the Great Artesian Basin and is composed of Jurassic sediments that contain coal measures, sandstone siltstone, conglomerate and oolitic limestone and outcrop to the north and upstream of the Site.

The Main Range Volcanics and Walloon Coal Measures are underlain by sandstone of the Marburg Subgroup, which consists of the Hutton and Marburg Sandstone of Jurassic age and are part of the GAB. Raiber and Cox (2012) consider the Walloon Coal Measures and Marburg Aquifer to be part of the GAB stratigraphy.

2.5 Hydrogeology

The hydrostratigraphy of the region is characterised by the four major geological units described above. A detailed discussion of the hydrogeology is presented in the 2017 ESA (AECOM, 2017b) and a summary is presented in Table 5.



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Table 5 Summary of regional hydrogeology

Hydrogeological unit Depth range within the IA Description/features Use

Oakey Creek Alluvium Up to 75 metres below ground level (m bgl).

Flow is generally in a westerly direction towards Oakey Creek and the Condamine River.

The alluvium consists of fluvial stream overbank deposits interbedded with discontinuous sequences of sand, silt, gravel and clay.

Overall, the aquifer grain size tends to coarsen with depth. The base of the aquifer consists of a coarse grained continuous basal gravel (i.e. Lower Oakey Creek Alluvium). The Lower Oakey Creek Alluvium has generally higher yields than the Upper Oakey Creek Alluvium.

Underlain by a clayey horizon, which partially confines the Lower Oakey Creek Alluvium from the underlying units.

The maximum extent of the alluvium is downstream of Oakey Creek where the width approaches 7 km.

Part of the Murray Darling Basin system.

The hydraulic conductivity (permeability) of the Oakey Creek alluvium is estimated between 0.1 and 75 m/day using pumping test data reported in the Stage 2C 2016 EI.

Estimates of specific yield for the unconfined Oakey Creek Alluvium, using groundwater level response to discharge, are about 11%. A specific yield of 8% is used in the Oakey Creek Groundwater Management Area as part of the water sharing rules (DNRM, 2015).

Easily accessed because of the shallow depth.

The Department of Natural Resources and Mines (DNRM) groundwater database indicated that the aquifer is used for irrigation, domestic purposes, livestock watering and edible gardens, and (historically) intermittent potable water via town water supply bores during extreme dry periods.



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Hydrogeological unit Depth range within the IA Description/features Use

Main Range Volcanics (Basalts)

The depth range is considered likely to vary from surface outcrops in the north and west of the Oakey Creek catchment, to greater than 50 m bgl. Regionally, the average thickness is around 70 m.

Discontinuous dual porosity aquifer with groundwater in the rock matrix and vesicles connected by fractures.

Managed under the Condamine Balonne Water Resource Plan.

The suggested bulk hydraulic conductivity of the basalt ranges from 0.004 to 4.6 m/day. This is dependent on fractures, joints and vesicles within the basalt (QWC, 2012). Site-specific hydraulic conductivity data indicates the competent basalt has low hydraulic conductivity, ranging from 0.001 to 0.018 m/day (average 0.01 m/day).

Used for irrigation, stock, and domestic and (historically) town water supplies (AECOM, 2016a).

Many of the bores to the south/south-east of the Site do not fully penetrate the full thickness of this unit.

Walloon Coal Measures

Up to 200 m in thickness beneath the IA.

Siltstone, mudstone with minor sandstone, coal and shale.

The coal seams are generally the more permeable units within a sequence of dominantly low permeability mudstones, siltstones or fine-grained sandstones.

Considered to form an effective aquitard between the Oakey Creek Alluvium and underlying GAB Hutton and Marburg Sandstone.

Raiber and Cox (2012) consider the Walloon Coal Measures to be part of the GAB stratigraphy.

The hydraulic conductivity has a range between 0.0006 and 0.9 m/day, with a median of 0.08 m/day (QWC, 2012).

The specific yield is 0.005% (QWC, 2012). Literature values for specific yield for basalt (weathered, fractured, and vesicular basalt) are about 1 to 5%.

The aquifer typically has a low hydraulic conductivity and consequently the groundwater yields are typically low, suitable only for stock supplies (AECOM, 2016a).

Water quality is typically brackish (Hillier, 2010).



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2.6 Groundwater Management and Use

2.6.1 On-Site Groundwater Use

Historically, groundwater at the Site was extracted from the lower zone of the Oakey Creek Alluvium aquifer for the following activities:

municipal water supply for drinking and domestic uses (historically supplied from Toowoomba Regional Council (TRC) wells on Site between 1960s and 1997)

aircraft cleaning

dust suppression

fire-fighting training

domestic use

irrigation

filling the Site swimming pool.

Groundwater abstraction at the Site was halted in January 2013.

The Site has been supplied with reticulated water from the Mt Kynoch Water Treatment Plant via the Oakey/Toowoomba pipeline since the construction of the pipeline in 1997. Prior to 1997, groundwater was used for all purposes on the Site, including drinking water (AECOM, 2015a), although anecdotal evidence suggests that the groundwater was not widely used for drinking because it was unpalatable. In 1997 the Site switched to town water supply for all water uses except irrigation, aircraft washing (only demineralised water), fire-fighting training and filling of the swimming pool. Use of groundwater to fill the swimming pool ceased in 2012.

2.6.2 Off-Site Groundwater Use

Groundwater is or has historically been extracted from private and public bores for uses including:

municipal supply (historically between the 1960s and 2012)

domestic purposes (cooking, showering, laundry, filling swimming pools)

irrigation of crops

watering of livestock and domestic pets

recreational purposes (swimming pools and irrigation of community and school sporting fields and parks)

commercial purposes (industry, hospital, mines, etc.).

As a precaution, in July 2014 Defence recommended that residents not drink water sourced from any underground water bores within the IA until further notice. Defence is providing water assistance on a case-by-case basis to residents within the IA who use groundwater for drinking water or domestic purposes.

The 2016 HHRA and 2017 HHRA Addendum identified the following precautions that could be followed by people living in the Oakey IA to minimise potential for ongoing PFAS exposure:

do not use groundwater for drinking water supply within the IA (including water used for cooking)

avoid or minimise using groundwater for bathing, showering, home swimming, paddling pools and/or sprinkler play in Groundwater Zone 1 and Zone 2

restrict consumption of home grown eggs from backyard poultry exposed to water in Groundwater Zone 1 and Zone 2 containing detectable PFAS (i.e. PFAS reported at concentrations greater than the laboratory LOR)

minimise consumption of the following until additional data can be collected to refine the HHRA:




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In areas where contamination of water has been identified (e.g. in underground, springs, water bores, dams, ponds or creeks), human exposure can be minimised by:

not drinking the water or using it to prepare food

not consuming food products (e.g. eggs, milk, fish, crustaceans (prawns, yabbies/crabs), fruit or vegetables) grown or produced using, or in, contaminated water

avoiding or minimise the use of the water for showering/bathing, sprinklers or to fill swimming pools due to the possibility of unintentionally drinking the water.

2.7 Surface Water

2.7.1 Regional Drainage System

The Site is located on a relatively flat alluvial plain, with Oakey Creek forming the major natural surface drainage feature (refer to Figure F1, Appendix A). The tributaries of Cooby Creek and Westbrook Creek flow into Oakey Creek. Further downstream of Oakey township, the tributaries of Doctor Creek and Lagoon Creek flow into Oakey Creek from the north.

Cooby Creek Reservoir is located in the headwaters of the Oakey Creek catchment, approximately 20 kilometres north-east of the Site (refer to Figure F1, Appendix A). The dam is a source of water supply to Toowoomba City. The Cooby Creek Reservoir is a rock fill embankment dam with an ungated spillway across Cooby Creek. The dam was constructed between 1938 and 1941. Cooby Creek Reservoir's lowest useable storage volume was recorded at 8% in January 2010. Following the rains of January 2011, Cooby Creek Reservoir's storage volume reached 100% (Toowoomba Regional Council, 2016).

Based on responses received to community water use surveys (discussed in Section 5.1.2.1) and observations made during field work, AECOM is not aware of people in the IA using surface water for drinking water; however, surface water is understood to be used by some landholders for irrigation or stock watering purposes.

2.7.2 On-Site Surface Water

Site surface water flow is principally from kerb and channel, piped systems, overland flow and open drains. All of the Site drainage lines are ephemeral. The Site surface water drainage network consists of approximately 23 km of pipe typically ranging in diameter between 300 mm and 1,200 mm and approximately 33 km of unlined open drainage lines. Infrastructure at the Site dates back to the 1970s (AECOM, 2013).

The hydrology of the Site is split between two major catchments:

Doctor Creek catchment – stormwater runoff in the northern part of the airfield is captured and diverted to Doctor Creek, which discharges into Oakey Creek, approximately 14 km downstream from the Site

Oakey Creek catchment – all operational areas of the Site are located within the Oakey Creek catchment; therefore, all flows entering the stormwater drainage system are directed via the four main drains towards Oakey Creek, located approximately 1 km to the south of the Site.



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The four main drainage channels are:

West Drain (drainage channel 1): extends from the south-west corner of the airfield, running in a southerly direction, merging with the central drain before discharging to Oakey Creek

Central Drain (drainage channel 2): aligned parallel to Orr Road, running in a south-westerly direction from the airfield across the Site and merging with the west drain before discharging to Oakey Creek

East Drain (drainage channel 3): aligned parallel to Swartz Road, running south from the south-east corner of the airfield across the Site and discharging to Oakey Creek. A portion of stormwater flows from East Drain into a private farm dam, located about 800 m south of the Site. Overflow from the dam returns into the East Drain and discharges into Oakey Creek (AECOM, 2015a)

Eastern Boundary Drain (drainage channel 4): aligned parallel with the eastern Site boundary, running in a southerly direction from the airfield and discharging to Oakey Creek.

The locations of these drains and other drainage at the Site are presented on Figure F2, Appendix A.

A weir on Oakey Creek creates a semi-permanent water body that receives and retains runoff from the surface water drains discharging from the Site. The location of the weir is shown on Figure F2, Appendix A.

2.7.3 Oakey Town Water Supply

Oakey is supplied with reticulated water from the Mt Kynoch Water Treatment Plant via the Oakey/Toowoomba pipeline.

Based on anecdotal information, it is understood that the regional water supply was periodically (in times of drought) supplemented by groundwater extracted from five bores located within the Oakey Creek Alluvium aquifer. When in operation, the bores could supply up to 70% of the town’s water supply (AECOM, 2015a). For a period of two years between 2008 and 2010, it is understood that this water was treated at the reverse osmosis (RO) plant at Ramsay Street. TRC has not abstracted groundwater for the town water supply since 2012 (TRC, 2016).

In July 2014, as a precautionary measure, Defence issued a recommendation that residents not drink groundwater until further notice. Defence currently provides alternative water supplies on a case-by-case basis to residents within the IA.

2.8 Water Quality Objectives and Environmental Values

The principal legislative basis for water quality management in Queensland is the Environmental Protection (Water) Policy (EPP) 2009, which identifies a process for identifying environmental values of waterways and establishing corresponding water quality objectives to protect identified environmental values. The Upper Oakey Creek is within the Condamine catchment and the following draft environmental values for the Upper Oakey Creek have been identified by Condamine Alliance (2017):

Aquatic ecosystems

Irrigation

Farm supply

Stock watering

Human consumption of wild biota

Visual appreciation (no contact with water)

Drinking water

Cultural and spiritual.



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Condamine Alliance (2017) has not scheduled environmental values/water quality objectives for the Upper Oakey Creek and it is noted that the main CoPC identified on-Site (PFAS) are not prescribed within the water quality objectives. In the absence of specific objectives, Condamine Alliance (2017) identifies technical water quality guidelines such as the Queensland Water Quality Guidelines (DERM 2009) and Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC and ARMCANZ 2000) as providing default water quality objectives for the protection of ecological receptors. The guideline screening values for drinking water and recreational activities published in the Department of Health (2017) guidance and Australian Drinking Water Guidelines (NHRMC, 2017), are considered to provide suitable water quality objectives for the protection of human health.



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3.0 Issues Identification This stage of the HHRA identifies the key issues and establishes a context for the risk assessment (enHealth, 2012b).

3.1 Rationale for Undertaking the HHRA

Fire-fighting training and emergency response services involving the use of AFFF containing PFAS have occurred at the Site since the 1970s. AFFF products are fire suppressing foams that were used at the Site for fire-fighting training activities and emergency response for approximately 40 years. The main AFFF product used historically by Defence was 3M Lightwater™, which contains PFAS including PFOS and PFOA. From 2004, the Department of Defence commenced phasing out its use of legacy aqueous film forming foams (AFFF) containing PFOS and PFOA as active ingredients and progressively transitioned to a product called Ansulite for use on the Defence estate.

The product currently used by Defence does not contain PFOS and PFOA as active ingredients, only in trace amounts. AECOM understands that Ansulite is used by Defence only in emergency situations where human life is at risk, or in controlled environments to test equipment, and any Ansulite used by Defence is captured and treated and/or disposed of at licensed waste disposal facilities in accordance with best practice regulations, and standards. Based on anecdotal evidence, for the purposes of this report, it has been assumed that Defence commenced phasing out the use of AFFF products containing PFOS and PFOA at the Site from 2005. This assumption has not been verified by Defence (AECOM, 2016b).

Subsequent environmental investigations (refer to Section 4.1) have identified environmental impacts from PFAS both at the Site and in the surrounding IA. The nature and extent of PFAS impacts in soil, sediment, surface water and groundwater on- and off-Site are discussed in more detail in Section 4.3. Groundwater is understood to be currently (or to have been historically) used in the IA for a range of purposes, including potable water supply and domestic and commercial activities (including agriculture). Defence currently provides alternative water supplies on a case-by-case basis to stakeholders within the IA, and the 2016 HHRA and 2017 HHRA Addendum identified the following precautions that could be followed by people living in the Oakey IA to minimise potential for ongoing PFAS exposure:

do not use groundwater for drinking water supply within the IA (including water used for cooking)

avoid or minimise using groundwater for bathing, showering, home swimming, paddling pools and/or sprinkler play in Groundwater Zone 1 and Zone 2

restrict consumption of home grown eggs from backyard poultry exposed to water in Groundwater Zone 1 and Zone 2 containing detectable PFAS

minimise consumption of the following until additional data can be collected to refine the HHRA:







not drinking the water or using it to prepare food

not consuming food products (e.g. eggs, milk, fish, crustaceans (prawns, yabbies/crabs), fruit or vegetables) grown or produced using, or in, contaminated water



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avoiding or minimise the use of the water for showering/bathing, sprinklers or to fill swimming pools due to the possibility of unintentionally drinking the water.’

The data from these previous investigations was reported in the 2016 HHRA. The 2016 HHRA report identified a number of data gaps or uncertainties requiring further assessment (refer to Section 1.2). Subsequently, additional investigation works have been conducted to further characterise the nature and extent of PFAS impacts and potential for human exposure to PFAS in soil, groundwater, surface water, sediment, terrestrial plants, eggs, and aquatic fauna grown within the IA for human consumption. This report provides an updated assessment of potential risk to human health for the Site and surrounding IA incorporating these additional data.

3.2 Stakeholders

The stakeholders relevant to the HHRA include:

residents, employees of businesses and people who undertake recreation activities within the IA

Defence

Queensland Government and regulatory authorities

Commonwealth Government.

3.3 HHRA Objectives

The objective of this HHRA is to quantitatively assess the potential risk to health for identified people within the IA, as a result of direct contact exposure to PFAS detected in soil, groundwater, surface water and sediment, and secondary exposure to PFAS due to bioaccumulation in terrestrial biota and aquatic biota in the human food chain. This HHRA follows from and builds on the previous quantitative risk assessment reported in the 2016 HHRA (refer to Section 1.1).

The HHRA aims to provide the following information related to the identified environmental PFAS impacts:

What groups of people in the IA might be exposed.

How people in the IA might be exposed.

The estimated magnitude of intakes for these groups compared to typical Australian PFAS intakes from background sources.

Whether the estimated PFAS intakes for people in the IA might exceed the TDI, which is a daily intake that is expected to be without appreciable health risk, based on toxicological studies and incorporating a range of uncertainty (safety) factors.

- Pathways where PFAS exposure is estimated to be low and expected to be associated with no adverse health effects.

- Pathways where PFAS exposure is estimated to have the potential to be elevated in comparison to the TDI, and that can be managed to most effectively reduce exposure to PFAS in the future (as recommended by Queensland Health).

3.4 Risk Management Decisions

While risk management is a separate process from risk assessment, the following outcomes of the HHRA will be relevant to subsequent risk management decisions, as follows:

Identification of the relative contribution to the overall risk estimate from each exposure pathway will help to inform which potential exposure pathways may need to be mitigated to effectively reduce overall risks.

Assessment of the sensitivity of the risk assessment outcomes to the identified data gaps and uncertainties will provide input to decisions regarding the requirement for, and scope of, future stages of investigation.



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4.0 Data Collection, Evaluation and Conceptual Site Model

4.1 Data Collection

The data utilised in the HHRA were from samples collected in the IA as part of investigations completed prior to 25 June 2017, and were reported in the sources listed in Section 4.1.1. These data are tabulated in Appendix B. The nature and extent of PFAS impacts detected in various media are summarised in Section 4.3.

4.1.1 Previous Investigations

A number of environmental investigations have been conducted since 2010 to assess the presence of PFAS in association with the Site. A summary of these and other historical contamination investigations in relation to the Site is presented in the 2017 ESA (AECOM, 2017b).

The scope of this HHRA is to undertake an assessment of the potential human health risk to identified on- and off- Site human receptors as a result of direct contact exposure and secondary exposure to PFAS impacted environmental media.

The analytical data used in this HHRA have primarily been sourced from the following documents.

Stage 1 and Stage 2 Environmental Investigation at Army Aviation Centre, Oakey, Queensland (URS, 2010)

Stage 2 (Part 2) Environmental Investigation Army Aviation Centre Oakey (Coffey, 2011)

Environmental Investigation – Stage 3 Risk Assessment and Remediation Design, Army Aviation Centre Oakey (AACO) (Parsons Brinckerhoff [PB], 2012)

Stage 3 Risk Assessment and Remediation Design at Army Aviation Centre Oakey – Groundwater Monitoring Event, December 2012 (PB, 2013a)

February 2013 Addendum to Stage 3 Risk Assessment and Remediation Design at Army Aviation Centre Oakey Groundwater Monitoring Event (PB, 2013b)

Stage 1 and Stage 2 Environmental Investigation, Army Aviation Centre Oakey – Offsite Assessment 2013-2014 (Rev 1) (AECOM, 2015c)

Stage 1 and Stage 2 Environmental Investigation, Army Aviation Centre Oakey - Offsite Assessment – Addendum (Aug-Nov 2014 Sampling Report) (Rev 1) (AECOM, 2015d)

Stage 1 and Stage 2 Environmental Investigation, Army Aviation Centre Oakey – Offsite Assessment - Addendum II (Dec 2014 - May 2015 Sampling) (Rev B) (AECOM, 2015e)

Stage 1 and Stage 2 Environmental Investigation, Army Aviation Centre Oakey – Drain Sediment Sampling (April 2015) (AECOM, 2015f)

Stage 2C Environmental Site Assessment, Army Aviation Centre, Oakey, 60438981 Final, 26 July 2016 (AECOM 2016a)

Stage 2C Environmental Investigation- Human Health Risk Assessment, Army, Aviation Centre, Oakey, 60438981 Final, 01 September 2016 (AECOM 2016b)

Addendum to Stage 2C Environmental Investigation – Human Health Risk Assessment, Sensitivity Assessment of HHRA Outcomes for Food Standards Australia New Zealand Tolerable Daily Intake, 60438981, March 2017 (AECOM 2017a)

Stage 2C Environmental Investigation – Environmental Site Assessment, July 2017 (in preparation) (AECOM 2017b)

Stage 2C Environmental Investigation – Ecological Risk Assessment, July 2017 (in preparation) (AECOM 2017c).



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4.1.2 Data Presented in this Report

The 2016 HHRA report identified a number of data gaps or uncertainties requiring further assessment (refer to Section 1.2). Subsequently, additional investigation works have been conducted to further characterise the nature and extent of PFAS impacts and potential for human exposure to PFAS in soil, groundwater, surface water, sediment, terrestrial plants, and aquatic fauna grown within the IA for human consumption.

A Sampling, Analysis and Quality Plan (SAQP) was developed by AECOM (2017a) for the collection of biota samples to address these data gaps, taking into account existing knowledge of biota growth and consumption in the IA.

The sampling works were completed by AECOM in accordance with the SAQP between February and April 2017, and included collection of samples of the biota discussed below.

4.1.2.1 Plants Consumed by Humans (i.e. fruit and vegetables)

The investigation involved the collection of additional fruit and vegetable samples co-located with soil and irrigation water (groundwater or surface water) at selected residential properties within the IA, to address the data gap identified in the 2016 HHRA (refer to Section 1.2). The objective was to further assess the potential for PFAS uptake by plants grown for human consumption at residential properties in the IA, and to characterise the range of PFAS concentrations that may be encountered in these plant tissues.

The scope of work for the collection of fruit and vegetable samples included selecting sampling locations based on a community survey that identified where fruit and vegetables with potential PFAS exposure were currently grown and were available for Defence to collect samples.

The aim was to collect 10 plant samples from each of eight different plant families, at up to 20 properties within the IA (i.e. up to 80 primary fruit and vegetable samples in total). Based on the suitability of properties for sampling and the availability of specimens at the time of sampling, 78 primary fruit and vegetable samples from 15 plant families were collected across 17 properties, representing a range of produce, including the following eight plant families that were originally targeted:

Asteraceae (e.g. artichoke)

Brassicaceae (e.g. cabbage)

Convolvulaceae (e.g. sweet potato)

Cucurbitaceae (e.g. pumpkin)

Poaceae (grasses)

Rosaceae (e.g. apples)

Rutaceae (e.g. citrus)

Solanaceae (e.g. tomatoes).

Refer to Appendix C for the 2017 fruit and vegetable sampling methodology and observations, and Appendix D for associated laboratory certificates and data validation. Analytical data for plant samples collected in 2016 and 2017 are presented in Table 10, Appendix B, and summarised in Section 4.4.

4.1.2.2 Backyard Chicken Eggs Consumed by Humans

The investigation involved the collection of additional eggs from backyard chickens co-located with soil and chicken drinking water to address the data gap identified in the 2016 HHRA (refer to Section 1.2). The objective was to assess PFAS residues in eggs from backyard chickens exposed to varying concentrations of PFAS in water in the IA.



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The scope of work for the collection of backyard chicken eggs included selecting sampling locations based on a community survey that identified where backyard chickens with potential PFAS exposure were currently raised within the IA to provide eggs for human consumption and were available for Defence to collect samples.

The original scope comprised the collection of up to 30 backyard eggs from up to 10 properties located within the IA. Based on the suitability of properties for sampling at the time of the sample collection event for the 2017 HHRA, 27 chicken eggs, four duck eggs and one goose egg were collected from 11 properties. The duck and goose eggs were noted to have similar magnitude PFAS concentrations to the chicken eggs, and therefore the assessment of chicken egg consumption in the HHRA is also considered representative of potential for PFAS intakes from consumption of these other types of poultry eggs.

Refer to Appendix C for backyard egg sampling methodology and observations, and Appendix D for laboratory certificates and data validation. Analytical data are presented in Table 11, Appendix B and summarised in Section 4.4.

4.1.2.3 Yabbies, Mussels and Fish Consumed by Humans

The investigation involved the collection of yabbies and mussels co-located with sediment and surface water to address the data gap identified in 2016 HHRA (refer to Section 1.2). The objective was to further assess the potential range of PFAS concentrations that may be encountered in the edible portion of aquatic biota (specifically, yabbies and freshwater mussels), which may be collected by recreational fishers from publicly accessible waterways in the IA.

The scope of work for the collection of aquatic biota included sampling of yabbies and mussels from 10 locations from each of the following waterways: Oakey Creek, Westbrook Creek, Doctor Creek and an upstream reference location (Cooby Creek Reservoir).

The original scope involved the collection of up to 40 primary yabby and 40 primary mussel samples across the four local waterways. Based on the availability of specimens at the time of the sampling event for the 2017 HHRA, 45 yabbies and one mussel were collected from Oakey Creek and Doctor Creek.

Fish tissue samples collected as part of the 2017 ERA also supplemented the aquatic biota data in the HHRA. The scope of work consisted of 21 fish collected from the local waterways. Due to the availability of fish at the time of the sampling event for the 2017 HHRA, a total of 14 fish were collected from Oakey Creek and Westbrook Creek.

Refer to Figure F6, Appendix A for aquatic biota sampling locations.

Refer to Appendix C for aquatic biota sampling methodology and observations, and Appendix D for laboratory certificates and data validation. Analytical data are presented in Table 12, Appendix B and summarised in Section 4.4.

4.2 Data Evaluation

4.2.1 Data Quantity

The investigations listed in Section 4.1.1 included collection of samples of soil, groundwater, sediment, pore water, surface water from on- and off-Site, and aquatic and terrestrial biota (off-Site only). Figure 3 to Figure 6 in Appendix A show the on-Site soil and off-Site groundwater, sediment and surface water, pore water and aquatic biota sampling locations considered in this HHRA. No figure depicting the locations of soil and terrestrial biota samples on off-Site properties has been included, for confidentiality reasons.

It is noted that on-Site groundwater, surface water, sediment and pore water data have been included in Appendix B to inform the development of the CSM, but have not been quantitatively assessed in this HHRA, as on-Site soil data are considered to be most relevant to on-Site personnel exposures (refer to Section 4.8.4).

Overall the data quantity is considered to be sufficient for refinement and characterisation of on- and off-Site areas in the IA.

Table 6 summarises the number of samples for each data set that were considered in this HHRA.



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Table 6 Summary of data quantity considered in this HHRA

Matrix Type # of Sampling Locations

# of Primary Samples

Source Reference Data used in the HHRA

On-Site

Soil 48 48

URS, 2010

Coffey, 2011

PB, 2013

AECOM, 2015a-d

AECOM, 2016a & b

AECOM, 2017b & c

All available shallow soil data collected from depths between 0.0 – 0.1 m bgl across the Site (excluding the western portion of the Site that is currently leased for cotton production purposes; refer to Section 4.4.1) have been used in the HHRA. This depth range is considered most representative of soils that may be incidentally contacted by on-Site personnel during routine non-intrusive activities. Intrusive activities are subject to Defence management procedures on-Site.

Off-Site

Soil 183 183

AECOM, 2015a-d

AECOM, 2016a-b

AECOM, 2017b & c

All available shallow soil in areas irrigated with groundwater containing detectable PFAS, collected from depths between 0.0 – 1.0 m bgl have been used in the HHRA.

This depth range is considered most representative of soils that may be incidentally contacted by off-Site residents during routine activities, including non-intrusive activities and shallow digging in gardens.

Surface Water 53 53

AECOM, 2015a-d

AECOM, 2016a-b

AECOM, 2017b & c

All available surface water data from Oakey Creek, Doctor Creek and Westbrook Creek have been used in this HHRA.

Surface water data from Cooby Creek Reservoir were not included when evaluating potential exposures inside the IA.

Sediment 48 48

PB, 2013

AECOM, 2015a-d

AECOM, 2016a & b

AECOM, 2017a & b

All available sediment data from Oakey Creek, Doctor Creek, and Westbrook Creek have been used in this HHRA.

Sediment data from Cooby Creek Reservoir were not included when evaluating potential exposures inside the IA.



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Groundwater in Oakey Creek Alluvium aquifer

159 349

PB, 2013

AECOM, 2015a-d

AECOM, 2016a & b

AECOM, 2017a & b

Groundwater samples collected in the Oakey Creek Alluvium have been collected from 159 locations off-Site between 2013 and 2017. A total of 99 locations have been sampled at least twice in this period. Of these, 94 locations were sampled during the current (2017) stage of environmental investigation, providing data considered to be representative of current environmental conditions. Of these groundwater sampling locations, 123 were extraction bores on private property. It is assumed that private bores without well construction data are installed in the more easily accessed Oakey Creek Alluvium aquifer, owing to its shallow depth and generally acceptable salinity and higher yield than the deeper aquifers (Main Range Volcanics and Walloon Coal Measures).

Groundwater in Walloon Coal Measures and Main Range Volcanic aquifers

15 26

AECOM, 2015a-d

AECOM, 2016a & b

AECOM, 2017a & b

Groundwater samples collected in the deeper hydrogeological units were characterised by a total of 26 primary samples collected at 15 locations. Of these groundwater sampling locations, 13 were extraction bores on private property, where six were sampled at least twice between 2014 and 2017. The remaining two deep aquifer monitoring bores were installed during environmental investigation in 2017.

Fruit and vegetables 19 123 AECOM, 2016a & b

AECOM, 2017a & b All available home grown fruit and vegetable data were used in this HHRA.

Yabbies and mussels 21 46 AECOM, 2017a & b

All available yabby data were used in this HHRA. Only one mussel sample was collected from the local waterways, and as such, consumption of mussels has been excluded from this assessment as there was insufficient information to consider it as a significant pathway for chronic dietary exposure.



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Fish 8 44 AECOM, 2017a-c

All available fish data are included in Appendix B. The selection of samples for consideration in the HHRA was based on fish size (fish <10 cm were considered unlikely to be kept or consumed), whether samples were analysed whole or filleted (whole fish samples were not included) and whether fish species were commonly considered edible. Refer to Section 5.5.1.1.

Fish tissue data from Cooby Creek Reservoir were collected for the purpose of evaluating whether fish tissue PFAS concentrations could be associated with non-Site sources and were therefore not included when evaluating potential exposures inside the IA.

Backyard chicken eggs 12 62 AECOM, 2016a & b

AECOM, 2017a & b

All available backyard chicken egg data were used in the HHRA. It is noted that four duck eggs and one goose egg were also collected within the IA. The duck and goose eggs were reported to have similar magnitude PFAS concentrations to the chicken eggs, and therefore the assessment of chicken egg consumption in the HHRA is also considered representative of potential for PFAS intakes from consumption of these other types of poultry eggs.

Cow milk 2 3 AECOM 2016 a & b

All available cow milk data were used in the HHRA. It is noted that sheep milk was sampled in 2016; however, as there was no information to suggest that people within the IA consume sheep milk, these data were not considered further when estimating human intakes of livestock milk in the 2016 HHRA.



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Cow blood serum 2 16 AECOM 2016 a & b

All available cow blood serum data were used in the HHRA. It is noted that sheep blood serum was sampled in 2016; however, the maximum PFAS detections were lower than measured in samples of cattle blood serum. Because the serum–muscle tissue PFOS ratios reported for sheep and cattle (ToxConsult, 2016a) are similar, it is expected that the magnitude of estimated PFOS concentrations in cattle muscle tissue is greater than in lamb tissue. No information was found in the literature to inform the estimation of PFHxS concentrations in lamb tissue (ToxConsult, 2016b). Therefore the assessment of red meat consumption in the HHRA was based on blood serum data for cattle, which is considered to be conservative for consumers of sheep meat.



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4.2.2 Data Quality

4.2.2.1 Previous Investigations

The historical analytical data that were used in this HHRA have been reviewed within each individual previous report, as outlined above in Section 4.1.1. Validation of the historical data used in both the 2016 HHRA and 2017 HHRA has been presented in the 2016 HHRA, and thus has not been further detailed in this report.

The data validation process includes checking the analytical procedure compliance and an assessment of the accuracy and precision of the analytical data from a range of quality control measurements generated from both the field sampling and laboratory analytical programs. Overall, the analytical data from previous investigations incorporated into the HHRA were considered to be valid in terms of precision and accuracy of the primary data sets and representative of concentrations of the analysed compounds in the media tested. In summary, the data validation process yielded the following outcomes for the investigations conducted during the Stage 2C 2017 EI:

AECOM (2017b) – ‘the data validation for the 2017 Stage 2C EI data concluded that for the purposes of the investigation, the data are suitable for interpretation and acceptable for use in the ESA’

AECOM (2017c) – ‘the overall quality of the analytical data produced was considered to be of an acceptable standard for interpretative use in the ERA.’

4.2.2.2 Investigations Reported in this Report

Data reported for the first time within this report (and not previously reported) are outlined in Section 4.1.2. A summary of data assessment for these investigations is detailed below.

4.2.2.2.1 Plants Consumed by Humans (i.e. fruit and vegetables)

The primary laboratory for the analysis of PFAS in fruit and vegetable samples was Australian Laboratory Services (ALS), based in Sydney. The secondary laboratory for fruit and vegetable sample analysis was National Measurement Institute (NMI), also based in Sydney. Data validation of the Stage 2C 2017 EI fruit and vegetable samples is provided in Appendix D.

The following was noted with regards to the laboratory data:

The duplicate sample (QC12-170417) for fruit sample FLH86-170407 was lost during transit to Sydney. Both the primary sample and the triplicate quality control (QC) sample reported PFAS concentrations below LOR; therefore, the data are deemed acceptable for the purpose of this report.

It is considered the overall quality of the analytical data produced is acceptable for use in the HHRA.

4.2.2.2.2 Backyard Chicken Eggs

The primary laboratory for the analysis of PFAS in backyard chicken egg samples was NMI. Validation of the analytical data is presented in Appendix D.

The following was noted with regards to the laboratory data:

One matrix spike exceedance was reported for Laboratory QC sample (Spiked Egg sample C L1565). The exceedance was due to the high concentration in the primary sample, resulting in a positive bias to spike recovery.

Surrogate spike recovery exceedances for PFDoA (157%), PFUdA (180%) and PFDoA (164%) were reported in laboratory reports RN1162010 and RN1162013. The exceedances were due to matrix interference (which is not uncommon in biota samples) and are not considered to affect the results.




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4.2.2.2.3 Yabbies, Mussels and Fish Tissue

The primary laboratory for the analysis of PFAS in aquatic biota samples was NMI, and the secondary lab for yabby analysis was ALS. Validation of the analytical data is presented in Appendix D. The following was noted with regards to the laboratory data:

Laboratory duplicate exceedances were reported for PFDA (47%) and PFDoA (43%) in duplicate remainder sample B L1566. The exceedances were due to the heterogeneity of the flesh type and are not considered to affect the results.

Surrogate spike recovery exceedances were reported in laboratory reports RN1158627 (for PFBuA, PFNA, 6:2 FTS and 8:2 FTS), RN1161728 (for PFHxA, PFNA, PFNA, PFUdA, PFDoA, PFHxS, 6:2 FTS, and 8:2 FTS) and RN1161058 (for PFHxA, PFOA, PFNA, PFDoA, 6:2 FTS and 8:2 FTS). Exceedances were due to matrix interference and are not considered to affect the results.

RPDs exceeding acceptable limits were reported for intra-laboratory duplicate sample pair AACO-AFA-444-5-FAH149A_172303A (AACO-AFA-444-5-FAH149B_172303A) for PFOS (43%), PFHxS (144%), PFOA (131%), PFDA (50%), PFUnDA (53%). Exceedances were due to the heterogeneity of the flesh type and are not considered to affect the results.

RPDs exceeding acceptable limits were reported for inter-laboratory triplicate sample pair AFA-444-5-FAH149A (N17/009022TRIP) for PFOS (186%), PFHxS (133%), PFOA (67%), PFDoA (75%). Exceedances were due to the heterogeneity of the flesh type and are not considered to affect the results.


4.2.3 Data Evaluation Conclusion

Overall, the analytical data incorporated into the HHRA as outlined in Section 4.2 above were considered to be valid in terms of precision and accuracy of the primary data sets and representative of concentrations of the analysed compounds in the media tested.

4.2.4 Data Gaps

Identified data gaps that remain at the time of preparation of this HHRA (following the completion of the 2017 ESA), their significance to the outcomes of the HHRA, and the manner in which they have been addressed herein, are summarised in Table 7.



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Table 7 Data Gaps

Data gap Potential significance Manner in which addressed in HHRA

Livestock blood serum sampling

Livestock blood serum samples were collected during the 2016 investigation; no additional samples were collected during 2017. Commercial food producers (livestock meat production) have been identified in all three Groundwater Zones; however, livestock blood sample data were only available for properties in Groundwater Zone 1, and from a limited number of livestock. There is therefore uncertainty about PFAS concentrations in livestock blood serum in the other Groundwater Zones.

The PFAS concentrations in sheep and cattle blood serum for Groundwater Zone 2 and Zone RoIA were theoretically estimated based on the soil and groundwater EPC for each zone, and adopting the simple first order one compartment steady state pharmacokinetic model described in Appendix G20. PFAS concentrations in muscle tissue were then estimated by adopting empirical blood serum to muscle tissue transfer factors from published, peer-reviewed literature.

Livestock milk sampling Cow milk samples were collected during the 2016 investigation; no additional samples were collected during 2017. Cow milk data are only available for properties in Groundwater Zone 1, and from a limited number of livestock. There is therefore uncertainty about PFAS concentrations in cattle milk in the other Groundwater Zones.

The PFAS concentrations in cow milk in Groundwater Zone 2 and Zone RoIA were estimated based on theoretical PFAS concentrations in cattle blood serum from each Zone (which were in turn estimated based on the soil and groundwater EPC for the respective Zone), and adopting empirical blood serum to milk transfer factors from published, peer-reviewed literature.

It is noted that sheep milk was sampled in 2016; however, as there was no information to suggest that people within the DA consume sheep milk, these data were not considered further when estimating human intakes of livestock milk in the 2016 HHRA.



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Fruit and vegetable sampling Fruit and vegetable samples available at the time of sampling were restricted to those being grown at the time the fieldworks were conducted. Uncertainty remains as to whether other types of fruit and vegetables may uptake PFAS.

As discussed in Section 5.5.2.3, the fruit and vegetable sampling completed in the Oakey IA provides sufficient evidence that exposure to PFAS via consumption of fruit and root/tuber vegetables is not a complete pathway. Exposure to PFAS via consumption of leafy green vegetables has been identified as a complete pathway based on samples collected in Groundwater Zone 2. However, insufficient samples are available to evaluate whether this is a complete pathway for the other two Groundwater Zones.

In 2017 AECOM designed and facilitated a Plant PFAS Uptake Study, located at Royal Australian Air Force (RAAF) Base Williamtown, to determine theoretical uptake factors which could be utilised within a HHRA. Data from the Plant PFAS Uptake Study have been included in this HHRA for the purpose of estimating theoretical PFAS concentrations in leafy green vegetables from Groundwater Zone 1 and Zone RoIA.

Freshwater mussel sampling Limited mussel samples collected in Oakey Creek, Doctor Creek and Westbrook Creek.

Mussel sampling was attempted in at least 10 locations on each of Oakey Creek, Westbrook Creek and Doctor Creek. In general, it was noted that the habitat along these waterways was not suitable for mussel growth. Only one mussel sample was collected, from Oakey Creek, and was not considered a representative dataset of potential dietary intakes from long term consumption. This pathway was therefore excluded from this HHRA.

TRV were not available for all PFAS that were detectable in environmental media and biota samples.

Potential risk from exposure to other PFAS has not been quantitatively assessed.

As discussed in Section 4.6, for the samples used to inform this HHRA, the combined concentrations of PFOS and PFHxS (and to a lesser extent, PFOA and PFHxA) typically contribute to at least 90% of the detected PFAS in environmental media and biota (excluding fish, surface water and on-Site groundwater where the sum of PFOS, PFOA, PFHxS and PFHxA ranged between approximately 59-80% of the detected PFAS). The quantitative assessment of exposure to these four PFAS for which TRV are available is therefore considered to be sufficiently representative of potential risks associated with exposure to all PFAS detected in the environment.

A wider range of PFAS was detected in surface water samples, and this corresponded with a similar range of PFAS detected in fish tissue samples.



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TRV for use in Australian HHRA are not available for other PFAS, including the longer chain PFAS that may be bioaccumulative. There is currently no Australian guidance on how these other PFAS should be assessed. To account for this, the sensitivity assessment (refer to Section 8.3) includes an assessment of potential risks associated with exposure to a wider range of PFAS due to consumption of recreationally caught fish. This has been undertaken by summing the concentrations of perfluoroalkylsulfonic acids, perfluorooctanesulfonamides (FOSAs), perfluorooctanesulfonamidoethanols (FOSEs) and perfluorooctanesulfonamidoacetic acids (FOSAAs) and assessing these as equivalent in toxicity to PFOS, and summing the concentrations of perfluoroalkylcarboxylic acids (PFCAs), and telomer sulfonic acids and assessing these as equivalent in toxicity to PFOA (except 4:2 telomer sulfonate and 6:2 telomer sulfonate which were assessed combined with PFHxA). This approach is detailed in Appendix K9. Including this wider range of detected PFAS using this approach did not change the outcomes of the HHRA.

PFAS analysis in yabby samples

The range of PFAS that was analysed in the 2016 aquatic biota samples was not the same as those analysed in the 2017 yabby samples.

The following PFAS were detected in aquatic biota sampled in 2016, but were not analysed in yabby tissue samples collected in 2017 (as they were not included in the PFAS suite reported by NMI and were not previously identified as significant in terms of the total PFAS detected in environmental media), except for two duplicate samples:

Perfluorodecane sulfonic acid (PFDS) Perfluorooctane sulfonamide (FOSA) Perfluorotetradecanoic acid (PFTeDA) Perfluorotridecanoic acid (PFTrDA)

There is some evidence that longer chain PFCAs may be more highly bioaccumulated in biota than PFOS and PFHxS. However, as described above, the sensitivity assessment (refer to Section 8.3) concluded that consideration of these PFAS in fish tissue would not change the HHRA conclusions. It is considered that a similar outcome would apply to yabbies.



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The community surveys (summarised in Appendix E) were not responded to by 100% of the community in the IA.

Completion of the community survey was voluntary. A total of 127 responses to Survey 1 (in 2014), 202 responses to Survey 2 (in 2016) and 116 responses to Survey 3 (in 2017) were received by Defence. There is some uncertainty about whether the responses received characterise the entire community in the IA.

As discussed in Section 5.1.2.1, the surveys were intended to gather the following information:

Survey 1 was used to identify whether people had access to more than one source of water, and to develop the CSM by identifying what activities people in the IA used groundwater for at their property.

Survey 2 was used to identity potentially complete exposure pathways to update the CSM.

Survey 3 was used to obtain more information about how people in the IA would typically use their land to grow plant produce and livestock, together with quantities consumed and typical frequency.

The intent of the biota sampling program was not to sample every property or biota type, but rather to gain a sample set representative of commonly consumed plant and animal products. Therefore, utilising the available survey responses to inform sample locations was considered acceptable.

The survey responses were further supplemented by quantitative estimates for human behavioural exposure assumptions obtained from the recognised Australian and international resources listed in Section 5.1.2.2. Using published information to supplement the information gathered from the survey may result in variability in the level of conservatism relative to the actual community. Where there was uncertainty associated with survey responses, this was typically addressed by adopting conservative exposure assumptions likely to overestimate, rather than underestimate, potential PFAS exposures.



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Residential bore construction. The majority of residential bores do not have construction details; therefore, the screened depth cannot be verified.

The residential bores without construction details are assumed to be screened within the Upper Oakey Creek Alluvium. The 2016 ESA (AECOM 2016a) and 2017 ESA (AECOM 2017b) concluded that PFAS concentrations in the Upper Oakey Creek Alluvium were generally greater than concentrations in the Lower Oakey Creek Alluvium.

Although construction details are not known for many of the private bores, the available data are considered to be representative of water conditions at the point of use and therefore suitable to inform the HHRA.

Maximum groundwater PFAS concentrations were adopted when selecting EPC, to be conservatively protective of all users of groundwater in the IA.

A sensitivity assessment considering groundwater concentrations reported in the intermediate and deep aquifers has been prepared (refer to Section 8.3).

Surface soil samples BH229, BH172 and BH 173 stand out from the general trend of data found for Groundwater Zone RoIA.

Monitoring at these sampling sites shows longer chain PFCA present (PFDA 0.0005 to 0.0031 mg/kg and PFNA from 0.0003 to 0.0005 mg/kg) in addition to PFOS (range 0.0016 – 0.012 mg/kg), which is not consistent with the majority of soil samples that were sampled within this area.

Insufficient information was available to further examine the potential reason for the apparent greater concentrations of PFAS in these samples compared to other soil samples collected in Groundwater Zone RoIA. The soil EPC was based on the maximum PFAS concentrations in Groundwater Zone RoIA to account for this uncertainty.



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4.3 Nature and Extent of PFAS Impacts

The 2017 ESA (AECOM, 2017b) identified a number of activities on- and off-Site which are considered to have resulted in PFAS impacts on soil, sediment, surface water and/or groundwater. This information was used to inform investigations that have described the nature and extent of PFAS impact in the environment, which has subsequently been assessed in this HHRA. Environmental media which have been considered include groundwater, soil, surface water, sediment and terrestrial and aquatic biota, discussed separately in Section 4.3.1 to Section 4.4.4.

4.3.1 Groundwater

4.3.1.1 On-Site Groundwater

AECOM understands that there is currently no extraction of groundwater occurring at the Site for any use, and based on the depth to groundwater (in excess of 2 m bgl) it is considered unlikely that people on-Site would come into contact with groundwater via other routine activities. On this basis, there is no complete exposure pathway by which people on-Site may be exposed to groundwater (refer to further discussion in Section 5.0). A brief discussion regarding on-Site groundwater is presented below for the purposes of background information about on-Site source concentrations migrating off-Site.

A total of 99 primary groundwater samples were collected at 58 locations across the Site between January 2014 and April 2017. Concentration ranges are summarised in Table 8.

Table 8 On-Site groundwater results summary (2014 to 2017)

Analyte Number of samples analysed

Number of detections

Minimum concentration (µg/L)

Maximum concentration (µg/L)

PFOS 99 80 <0.01 375

PFHxS 99 57 <0.02 874

PFOA 99 76 <0.01 42.5

PFHxA 99 51 <0.02 198

PFAS concentrations in groundwater are locally elevated close to the potential source areas. Highest concentrations have been consistently detected at the former fire station and foam training area, indicating this area to be a significant source of PFAS at the Site.

PFAS have also been detected in areas of the Site away from the potential source areas. For example, during the 2017 Stage 2C EI, 11.7 µg/L PFOS was detected in groundwater in a sample collected from monitoring well MWN-I, which is located near the runway in the north-eastern portion of the Site. As there are no known potential PFAS sources in this area, and as it is hydraulically up-gradient of the known source areas, the contamination is inferred to be potentially related to the historical discharge of AFFF along the runway (AECOM, 2016a).

PFAS in groundwater have migrated off-Site beyond the down hydraulic gradient western boundary, as evidenced by the presence of PFAS in seven bores within 1 km of the western Site boundary during the 2017 Stage 2C EI. PFAS were also detected in groundwater further down hydraulic gradient in a bore, located approximately 1.7 km from the Site boundary. PFAS are likely to migrate across the western portion of the southern Site boundary, as evidenced by the detection of up to 4.01 µ/L PFOS at monitoring well MWA5-A, which is located along the western portion of the southern boundary.

As discussed above, because there is no complete exposure pathway by which people on-Site may be exposed to groundwater, the HHRA has focused on off-Site groundwater only.

4.3.1.2 Historical Off-Site Groundwater Investigations

An overview of off-Site groundwater investigations is presented in Section 4.3.1.2 to Section 4.3.1.3. Off-Site groundwater investigation locations are shown on Figure F3 and subfigures A to I in Appendix A, and analytical data are presented on Table 5, Appendix B.



38

A total of 267 historical off-Site primary groundwater samples from all aquifers (Oakey Creek Alluvium, Main Range Volcanics and Walloon Coal Measures) have been collected by AECOM from 138 locations off-Site between November 2013 and October 2016. Of these, 114 locations were sampled during the 20152016 stage of environmental investigation, providing data that were considered to be representative of the environmental conditions assessed during the 2016 HHRA. Concentration ranges are summarised in Table 9. The historical groundwater analytical data are presented in Table 5, Appendix B. A detailed discussion of historical off-Site groundwater was included in the 2016 HHRA.

Table 9 Off-Site groundwater historical results summary (2013 to 2016)





PFOS 267 152 <0.01 39.8

PFHxS 267 43 <0.02 33

PFOA 267 97 <0.01 2.03

PFHxA 267 28 <0.02 6.86

4.3.1.3 2017 Off-Site Groundwater Investigations

Off-Site groundwater investigation locations are shown on Figure F3 and subfigures A to I, Appendix A. Analytical data are presented in Table 5, Appendix B. Detailed discussion of the 2017 off-Site groundwater investigation is presented in the 2017 ESA (AECOM 2017b).

To address the data gaps identified by the 2016 HHRA (refer to Section 1.2), a total of 30 groundwater monitoring wells were installed off-Site in the IA. This included the installation of 21 shallow wells in the Oakey Creek Alluvium aquifer to depths of up to 50 m bgl, and nine wells in the deeper aquifers (Main Range Volcanics and Walloon Coal Measures) to depths of up to 75 m bgl.

A total of 95 primary groundwater samples have been collected by AECOM from 94 monitoring locations off-Site in the IA within the Oakey Creek Alluvium aquifer, and 13 primary groundwater samples have been collected from 13 monitoring locations off-Site within the deeper aquifers (Main Range Volcanics and Walloon Coal Measures) between January and June 2017. Concentration ranges are summarised in Table 10.

Table 10 2017 off-Site groundwater results (January to June 2017)





Oakey Creek Alluvium aquifer

PFOS 95 61 <0.01 21.4

PFHxS 95 66 <0.02 15.2

PFOA 95 42 <0.01 1.32

PFHxA 95 24 <0.02 3.04

Main Range Volcanics and Walloon Coal Measures aquifers

PFOS 13 4 <0.01 0.29

PFHxS 13 2 <0.02 0.11

PFOA 13 0 <0.01 <0.01



39





PFHxA 13 0 <0.02 <0.02

The majority of private groundwater bores do not have construction details available; therefore, the screened depth and targeted aquifer cannot be verified at all locations. It is assumed that the majority of private bores are installed in the more easily accessed Oakey Creek Alluvium aquifer, owing to its shallow depth and generally acceptable salinity and higher yield than the deeper aquifers (Main Range Volcanics and Walloon Coal Measures), discussed below.

The DNRM groundwater database indicated that the Oakey Creek Alluvium aquifer is used for irrigation, domestic purposes, livestock watering and edible gardens, and historically, for intermittent potable water via town water supply bores during extreme dry periods. Estimates of specific yield for the Oakey Creek Alluvium are approximately 11% and a specific yield of 8% is used in the Oakey Creek Groundwater Management Area as part of the water sharing rules (DNRM, 2015). Pumping tests conducted on three registered bores, as part of the 2017 Stage 2C EI, indicated high storage capacity within the alluvium, and that the groundwater extraction in the underlying bedrock units (Main Range Volcanics and Walloon Coal Measures) did not readily result in measureable induced flow impacts. The Main Range Volcanics and Walloon Coal Measures aquifers are also reported to be used for irrigation purposes; however, the yields are lower than in the Oakey Creek Alluvium aquifer. The specific yield for Main Range Volcanics ranges from 1 to 5% (QWC, 2012). Aquifer tests conducted on bore RN107812 during the 2017 Stage 2C EI indicated that Walloon Coal Measures is considered to provide low sustainable yields, as recognised from the low aquifer transmissivity (~1 m2/day) and limited storativity (0.0001).

On this basis, for the purposes of this HHRA, where insufficient data were available to determine screen depth, it was conservatively assumed the well was screened in the Oakey Creek Alluvium aquifer.

The 2017 data set, which includes new and existing monitoring wells and existing bores, has improved the understanding of the extent of PFAS contaminants off-Site in the IA. The highest PFAS concentrations recorded during sampling within the Oakey Creek Alluvium were reported in samples from monitoring wells GW34 (21.4 µg/L PFOS and 4.91 µg/L PFHxS) and RN147352 (11 µg/L PFOS and 15.2 µg/L PFHxS), which are located approximately 250 m and 350 m to the west (i.e. down hydraulic gradient) of drainage channel 1. Similar PFAS concentrations were also present in a new monitoring well, MWO-L-AL (9.02 µg/L PFOS and 7.87 µg/L PFHxS), and in an existing bore, GW27 (with 10 µg/L PFOS and 6.6 µg/L PFHxS), both located approximately 1 km to the south-west of the south-western corner of the Site boundary (refer to Figure F3E and Figure F3F, Appendix A. (Note that the location of monitoring wells GW34 has been withheld on request of the land owner).

The detection of higher PFAS concentrations in these wells indicates that the off-Site area containing higher concentrations (i.e. Groundwater Zone 2) extends further to the west than assessed in the 2016 ESA (AECOM 2016a). The increased extent is due to better monitoring well coverage and the inclusion of an increased data set for PFHxS from more recent monitoring results.

The 2017 ESA (AECOM 2017b) concluded that evaluation of the groundwater data trends over time suggests evidence for stable PFAS concentrations in groundwater on-Site and in areas adjacent to the Site. There is limited evidence for a minor increasing trend in hydraulically down-gradient off-Site bores, which is attributed to the migration of PFAS within groundwater towards the west.

Consistent with historical environmental investigations, concentrations of PFAS have also been detected in both the Main Range Volcanics and Walloon Coal Measures, but at lower magnitude concentrations than in the overlying aquifer. The 2017 data show the Walloon Coal Measures has trace concentrations of PFAS detectable in an area to the south of the Site. PFAS migration to the Walloon Coal Measures at MWO-X-WCM may be due to:

a steeper natural downward gradient due to extraction

thin or no competent basalt present



40

the presence of a thin transition zone

the construction of nearby bore RN107812, which may connect both aquifers at this location

the presence of fractured rock providing preferential flow pathways

the close proximity of Oakey Creek, which can act as a PFAS source that is captured in the bore RN107812 drawdown cone.

Overall, the data collated in 2017 indicate that the PFAS impacted groundwater within the Oakey Creek Alluvium extends off-Site in a westerly and south-westerly direction. The contaminant migration is considered to be influenced by:

regional groundwater flow

groundwater pumping by bores drawing from the Oakey Creek Alluvium

migration of PFAS impacted surface water along southerly orientated unlined drains and Oakey Creek with infiltration to groundwater

mobilisation of PFAS along Oakey Creek during periods of flow and recharge from stream flow into the groundwater system.

4.3.2 Review of Groundwater PFAS Detection Zones Adopted in the HHRA

The groundwater quality information obtained from environmental investigations conducted between 2013 and 2017 has been used to refine the extent of the off-Site PFAS detection zones in the IA (Groundwater Zone 1 and Groundwater Zone 2), compared to those presented in the 2016 HHRA.

Consistent with the approach adopted in the 2016 HHRA, PFOS and PFHxS were adopted as the indicator compounds for this evaluation because their detections have been more widespread than PFOA and PFHxA, and where the extended PFAS suite has been analysed, they account for a significant proportion of the total PFAS detected (refer to Section 4.5). Descriptive statistics for PFOS and PFHxS concentrations in off-Site groundwater collected between 2013 and 2017 were used to refine the Groundwater Zones. The assessment considered groundwater from wells screened within the Oakey Creek Alluvium aquifer, and where insufficient data were available to determine screen depth, it was conservatively assumed the well was screened in the Upper Oakey Creek Alluvium aquifer. Descriptive statistics for PFHS and PFHxS in off-Site groundwater in the IA are summarised in Table 11.

Table 11 Descriptive statistics for PFOS and PFHxS concentrations in off-Site Upper Oakey Creek Alluvium aquifer groundwater in the IA (to two significant figures)

Parameter PFOS concentration (µg/L) PFHxS concentration (µg/L)

10th percentile 0.01 0.02







100th percentile 39.8 33

Note: Statistics calculated based on the assumption that non-detects are equal to the LOR. Bolded values indicate the

concentration distributions adopted for zone refinement.



41

It is noted that nine out of 11 monitoring wells located in the vicinity of the confluence of drainage channel 1 and drainage channel 2 and their point of discharge into Oakey Creek, approximately 1 km south of the Site, represent the upper 5% of the distribution of reported PFOS concentrations. It is considered that this may reflect an impact on groundwater resulting from both lateral migration of groundwater from the Site and vertical leaching of surface water at the confluence of the drainage channels in this area. As it would be overly conservative in the HHRA to adopt PFAS concentrations in groundwater from this area as representative of elsewhere in the IA, the PFOS and PFHxS concentrations representing the 10th, 50th and 90th percentiles in the Oakey Creek Alluvium aquifer have been adopted to define the following three Groundwater Zones:

Groundwater ‘Zone 2’ is represented by the upper 10% of the distribution (90th percentile) of reported PFOS and PFHxS concentrations. The off-Site groundwater bores in this Groundwater Zone are located immediately to the south and south-west of the Site, and have the highest magnitude of PFOS concentrations off-Site in the IA, owing to closer proximity to the Site, along with a potentially greater PFAS contribution from vertical migration of surface water in the vicinity of drainage channels 1 and 2. AECOM understands that some of the groundwater extraction bores in this Groundwater Zone are used at properties where livestock are raised. Based on the new investigation locations and associated data, Groundwater Zone 2 was redefined to include an area approximately 950 m further to the west (i.e. in the direction of groundwater flow) of the area that was defined as Groundwater Zone 2 in the 2016 HHRA (refer to Section 2.5). Groundwater PFOS concentrations in Groundwater Zone 2 range from 0.03 µg/L to 39.8 µg/L and PFHxS concentrations range from 0.03 µg/L to 33 µg/L. The approximate area of the refined Groundwater Zone 2 is 306 hectares.

Groundwater ‘Zone 1’ is represented by concentrations ranging between the upper 10% and 50% (90th percentile to 50th percentile) of the PFOS and PFHxS distributions in the IA. The groundwater extraction wells are located further to the south and west of the Site, in which PFAS impacts on groundwater are inferred to have resulted from a combination of migration mechanisms including lateral groundwater migration and vertical migration from surface water. Comparison with Groundwater Zone 1 as presented in the 2016 HHRA indicates a reduction in extent, particularly to the eastern, north-western and southern portions of the Groundwater Zone. This is primarily due to the refinement in the range of PFAS concentrations that were adopted for inclusion and the addition of the third zone, discussed below. The concentrations of PFOS in this zone range from <0.01 to 4.9 µg/L and PFHxS concentrations range from <0.02 µg/L to 5.02 µg/L. The approximate area of the refined Groundwater Zone 1 is 609 hectares.

The remaining area within the IA, characterised as the Groundwater Zone ‘Rest of Investigation Area’ (RoIA), is represented by all PFOS and PFHxS concentrations lower than the 50th percentile. The majority of the groundwater extraction wells in this zone have not reported detections of PFAS, and are located outside Groundwater Zone 1 and Zone 2, within the boundary of the IA. The concentrations of PFOS within this area range from <0.01 µg/L to 0.08 µg/L and concentrations of PFHxS range from <0.02 µg/L to 0.27 µg/L. The approximate area of Groundwater Zone RoIA is 2,770 hectares.

Distributions of groundwater PFOS and PFHxS concentrations reported in the Oakey Creek Alluvium in Groundwater Zone 2, Zone 1 and Zone RoIA and associated box plots are presented in Figure 2 and Figure 3.



42

Figure 2 Box plot of PFOS distribution of all groundwater results in wells screened within the Oakey Creek Alluvium

Figure 3 Box plot of PFHxS distribution of all groundwater results in wells screened within the Oakey Creek Alluvium



43

Figure 2 and Figure 3 illustrate that Groundwater Zone 2 and Zone 1 are distinct areas in comparison to Groundwater Zone RoIA, and the distributions of PFOS and PFHxS data are generally similar. Table 12 summarises the number of primary groundwater samples from the three Groundwater Zones adopted in this HHRA, and the ranges of PFAS concentrations reported in each Groundwater Zone.

Table 12 Summary of groundwater data within the Oakey Creek Alluvium aquifer adopted in the HHRA (2013-2017)


(67 locations sampled)

Groundwater Zone 1


Groundwater Zone 2


COPC No

. sa

mp

les

Min

(µ

g/L

)

Max

(µ

g/L

)

No

. d

etec

ts

No

. sa

mp

les

Min

(µ

g/L

)

Max

(µ

g/L

)

No

. d

etec

ts

No

. sa

mp

les

Min

(µ

g/L

)

Max

(µ

g/L

)

No

. d

etec

ts

PFOS 125 <0.01 0.08 12 136 <0.01 4.89 110 88 0.03 39.8 88

PFHxS 125 <0.02 0.27 9 136 <0.02 5.02 53 88 0.03 33 47

PFOA 125 <0.01 0.05 2 136 <0.01 0.81 56 88 <0.01 2.03 80

PFHxA 125 <0.02 0.05 1 136 <0.02 0.76 18 88 <0.02 6.86 33

These three Groundwater Zones are illustrated on Figure F3, Appendix A. The extents of these Groundwater Zones are current as of the 2017 Stage 2C EI, but may be subject to change following the collection of additional data and/or the result of groundwater movement over time.

Table 12 above illustrates that there are 67 locations in Groundwater Zone RoIA, 58 locations in Groundwater Zone 1 and 34 locations in Groundwater Zone 2 from which samples have been analysed for the majority of PFAS on more than one occasion.

The quantity of data are considered to be sufficient for interpretative purposes.

4.3.3 Soil

4.3.3.1 Historical On-Site Soil Investigations

An overview of historical on-Site soil investigations from 2010 to 2016 is presented below.

Defence Operational Areas of the Site

A total of 103 historical on-Site primary soil samples have been collected at 39 locations on the Defence operational areas of the Site between 2010 and 2016. However, not all of these samples are considered relevant to the HHRA (refer to Table 6). Concentration ranges are summarised in Table 13.

Table 13 Historical on-Site soil analytical results summary – Defence operational areas of the Site



Minimum concentration (mg/kg)

Maximum concentration (mg/kg)

PFOS 103 41 <0.0005 30

PFOA 103 22 <0.0005 0.62

PFHxS 4 2 <0.0002 0.001

PFHxA 4 1 <0.0002 0.0012



44

Soil – Leased Areas

A total of 19 historical primary samples were collected in 2015 and 2016 at eight locations in the western portion of the Site, which is currently leased for agricultural purposes. Concentration ranges are summarised in Table 14.

Table 14 Historical on-Site soil analytical results summary – leased areas of the Site





PFOS 19 8 <0.0005 0.017

PFOA 19 0 <0.0005 <0.0005

PFHxS 8 4 <0.0005 0.0009

PFHxA 8 0 <0.0002 <0.0002

As discussed in the 2016 HHRA, PFAS concentrations are overall lower in the soils within the leased area of the Site, relative to the Defence operational areas of the Site associated with historical use of legacy AFFF, but comparable to areas of the Site around the runways where groundwater is understood to have been used for dust suppression. The 2017 ESA (AECOM, 2017b) concluded that the presence of detectable PFAS in surface soils is likely to be a result of a combination of:

surface transport by water during flooding events

use of groundwater containing PFAS for irrigation purposes.

4.3.3.2 2017 On-Site Soil Investigations

On-Site investigation locations are shown on Figure F4 and subfigures A to D, Appendix A. Analytical data are presented in Table 2, Appendix B. Detailed discussion of the 2017 on-Site soil investigation is presented in the 2017 ESA (AECOM, 2017b).

To address the data gaps identified by the 2016 HHRA (refer to Section 1.2), at total of 182 soil samples from 62 locations at the Defence operational areas on-Site were analysed for PFAS. Soil samples were collected from depths ranging from the surface to 97.6 m bgl. Soil sampling locations primarily focused on PFAS source areas that have been identified in previous investigations, and additional sampling was conducted to further assess the extent of impact. No soil sampling was conducted on the leased areas on-Site during the 2017 Stage 2C EI. Concentration ranges are summarised in Table 15.

Table 15 2017 on-Site soil results – Defence operational areas (February to June 2017)





PFOS 182 140 <0.0002 33.4

PFHxS 182 141 <0.0002 36.6

PFOA 182 102 <0.0002 5.49

PFHxA 182 128 <0.0002 14.5

Consistent with previous investigations, the highest PFOS concentrations in soil on the Site have been reported in potential source areas; specifically, the Former Fire Training Ground (33.4 mg/kg at location BH-N-O at 0.5 m bgl) and the current AFFF storage area (9.67 mg/kg at location BH-D2-H at 0.5 m bgl).



45

PFOS is consistently detected in near-surface soil (<0.5 m bgl) at all locations sampled across the Site. High PFOS concentrations are also present in the 0.5-2.0 m bgl depth interval, with very high concentrations present in the vicinity of several potential source areas including the former fire training ground and former fire station and foam training area. Below 2.0 m bgl, PFOS concentrations in soil are much lower at the locations sampled. Soils in the upper 0.1 m are considered most representative of soils that may be incidentally contacted by on-Site personnel during routine non-intrusive activities. Intrusive activities are subject to Defence management procedures on-Site.

4.3.3.3 Historical Off-Site Soil Investigations

Soil – Irrigation Areas

A total of 61 historical primary samples from 61 locations were collected during March and October 2016, from off-Site surface soils (from 0 to 1 m bgl) in the DA where groundwater containing detectable concentrations of PFAS have been identified as being used for irrigation purposes. Concentration ranges are summarised in Table 16.

Table 16 Historical off-Site soil analytical results summary – areas irrigated with groundwater





PFOS 61 57 <0.0005 0.04

PFOA 61 19 <0.0005 0.002

PFHxS 61 48 <0.0002 0.03

PFHxA 61 19 <0.0002 0.0051

It is noted that an additional 18 primary samples were collected during May and October 2016, after the sampling cut-off date for inclusion into the 2016 HHRA.

These sampling results confirmed that irrigation using groundwater containing detectable concentrations of PFAS has the potential to result in detections of PFAS in the associated irrigated soil. The soils were sampled from locations where the maximum groundwater PFOS concentration ranged between 0.6 µg/L and 39.2 µg/L; however, the magnitude of PFOS concentration in soil was not observed to correlate closely with the magnitude of PFOS concentration in groundwater. It was considered likely that the frequency, duration and application rate of irrigation water plus rain and flood events would influence the magnitude of PFAS concentrations detected in soil. Although uncertainty remains regarding these relationships, the data are considered representative of soils that may be encountered off-Site in the IA and therefore appropriate for use in the HHRA.

Soil – Other Areas

An additional 25 historical primary soil samples were collected from eight locations during installation of monitoring wells off-Site in the DA in October 2015. Concentration ranges are summarised in Table 17.

Although these data only provided limited spatial coverage of the DA, they provided a line of evidence that PFAS impacts in soil are unlikely to be widespread in the DA beyond areas where groundwater has been used for irrigation purposes or where flooding has occurred.



46

Table 17 Historical off-Site soil analytical results summary – soil samples collected during installation of monitoring wells off-Site in the DA





PFOS 25 1 <0.0005 0.0007

PFOA 25 0 <0.0005 <0.0005

PFHxS Not analysed Not analysed Not analysed Not analysed

PFHxA Not analysed Not analysed Not analysed Not analysed

It is noted that soil bores BH01A, BH01B and BH01C (located on the northeast corner of the AACO boundary) were listed as off-Site bores in the 2016 HHRA, but were determined as on-Site bores for the 2017 HHRA.

4.3.3.4 2017 Off-Site Soil Investigations

Analytical data are presented in Table 6, Appendix B. Detailed discussion of the 2017 off-Site soil investigation is presented in the 2017 ESA (AECOM 2017b).

Off-Site soil samples were collected as part of the following 2017 Stage 2C EI scopes of work:

Groundwater monitoring well installation – 101 primary soil samples were collected from new monitoring well locations. For shallow soil samples (ground surface to 1.5 m bgl), soil samples were directly collected using a hand auger. Shallow soil samples were collected to provide information on near-surface quality to provide data set on soil potentially impacted due to irrigation using impacted groundwater or migration of PFAS during flood inundation. The deeper bores (1.5 m bgl to target depth) were drilled using either a sonic rig, geoprobe or geotechnical rigs. Samples were collected from various depths where saturated soils were observed in both the upper and lower zones of the Oakey Creek Alluvium aquifer. Samples were analysed for the extended PFAS suite.

Loose non-residential surface soil – loose surface soils were collected by hand to understand the distribution of PFAS that may have migrated by wind resuspension (refer to Section 4.3.3.1) or by flood inundation. A total of 64 samples were collected of loose soil from the ground surface.

Component of biota sampling – 85 soil samples were co-located with fruit, vegetable and backyard egg samples to assess the relationship between soil and groundwater and the uptake of PFAS into home-grown fruit, vegetables and backyard eggs. The surface soil samples were collected from the plant root zone (typically, the upper 0.15 m of the profile) either by hand or using a hand auger. Samples were analysed for the extended PFAS suite (see Appendix C).

PFAS concentration ranges for off-Site primary soil samples collected during the 2017 ESA (AECOM, 2017b) in areas irrigated with groundwater containing detectable concentrations of PFAS are summarised in Table 18.

Table 18 2017 off-Site soil results (January to April 2017) – areas irrigated with groundwater





PFOS 85 82 <0.0002 0.11

PFHxS 85 62 <0.0002 0.066

PFOA 85 29 <0.0002 0.0036

PFHxA 85 17 <0.0002 0.005



47

Consistent with the 2016 HHRA, these data from off-Site locations indicates that the use of groundwater or surface water for irrigation has the potential to result in detection of PFAS in surface soils. However, there was a low correlation between the PFOS concentrations in groundwater and associated irrigated soil.

Concentration ranges of off-Site primary soil samples collected in other areas during the 2017 Stage 2C EI are summarised in Table 19.

Table 19 2017 off-Site soil results (January to June 2017) – other areas





PFOS 165 84 <0.0002 0.28

PFHxS 165 42 <0.0002 0.067

PFOA 165 18 <0.0002 0.0073

PFHxA 165 18 <0.0002 0.013

The maximum PFOS concentration was reported in the non-residential surface soil samples collected from the roadside (0.28 mg/kg PFOS and 0.013 mg/kg PFHxA at SSL18), located approximately 118 m north of the Site. Soil samples collected during the installation of monitoring well MWO-H-WCM, near the vicinity of drainage channel 1, reported maximum concentrations of PFHxS, PFOA and PFHxA from BH-H-WCM at 0.5 m bgl.

Given the persistent nature of PFAS and to allow a greater spatial coverage of the IA, all available soil data have been considered in this HHRA. Table 20 summarises the number of off-Site primary soil samples with respect to the three Groundwater Zones adopted in this HHRA (refer to Section 4.3.2) and the concentrations reported.

Table 20 Summary of off-Site soil data considered in the HHRA


(71 Locations Sampled)

Groundwater Zone 1

(64Locations Sampled)

Groundwater Zone 2

(104 Locations Sampled)

COPC

No

. sam

ple

s

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. det

ects

No

. sam

ple

s

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. det

ects

No

. sam

ple

s

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. det

ects

PFOS 110 <0.0002 0.28 50 95 <0.0002 0.075 60 131 <0.0002 0.18 114

PFHxS 110 <0.0002 0.040 18 95 <0.0002 0.011 43 131 <0.0002 0.067 91

PFOA 110 <0.0002 0.0007 9 95 <0.0002 0.0014 14 131 <0.0002 0.0073 43

PFHxA 110 <0.0002 0.013 5 95 <0.0002 0.0008 5 131 <0.0002 0.010 44

Table 20 above illustrates that there are 71 locations in Groundwater Zone RoIA, 64 locations in Groundwater Zone 1 and 104 locations in Groundwater Zone 2 which have been sampled for the purpose of soil characterisation off-Site. The quantity of data is considered to be sufficient for interpretative purposes.



48

4.3.4 Surface Water and Sediment

4.3.4.1 On-Site Surface Water and Sediment – Drainage Channels

Surface water and sediment from on-Site drainage channels are unlikely to be directly contacted by Site personnel during routine activities. It is assumed that potential exposure pathways for intrusive maintenance workers on the Site can be managed by Defence specifying minimum requirements for inclusion in health and safety plans for intrusive works to be undertaken on the Site. On this basis, there is no complete exposure pathway for on-Site surface water and sediment (refer to Section 5.0). A brief discussion regarding on-Site surface water and sediment is presented below.

A total of 24 primary surface water samples were collected at 12 locations across the Site between December 2014 and March 2017. Concentration ranges are summarised in Table 21.

Table 21 On-Site surface water results summary (2014 to 2017)





PFOS 24 23 <0.02 3.19

PFHxS 13 13 0.08 1.44

PFOA 24 21 <0.02 15.5

PFHxA 13 13 0.02 5.28

Maximum concentrations of PFAS were reported in samples collected from drainage channel 1, drainage channel 2 and drainage channel 3. The reported maximum PFOA concentration (in a sample collected at location SW21 in August 2015) was more than five times greater than concentrations reported at the same location in other samples collected between December 2014 and February 2016. However, the surface water sampled from SW21 in March 2017 resulted in a PFOA concentration of 10.1 µg/L; this variation in data may reflect the ephemeral nature of the water in the drains.

A total of 72 primary sediment samples were collected at 45 locations at drainage channels on the Site between December 2010 and January 2017. Concentration ranges are summarised in Table 22.

Table 22 On-Site sediment results summary (2010 to 2017)





PFOS 72 69 <0.0005 3.68

PFHxS 72 41 <0.0002 0.38

PFOA 72 59 <0.0002 1.05

PFHxA 72 39 <0.0002 0.087

Maximum concentrations of PFAS were reported in samples collected from drainage channel 1, drainage channel 2 and drainage channel 3. These data indicate that surface drainage channels are an important transport mechanism for PFAS off-Site.

As indicated above, there is not considered to be a complete exposure pathway for Site personnel to come into contact with on-Site surface water and sediment during routine activities, and it is assumed that potential exposure pathways for intrusive maintenance workers on the Site can be managed by Defence specifying minimum requirements for inclusion in health and safety plans for intrusive works



49

to be undertaken on the Site. As such, the discussions henceforth will focus on off-Site surface water and sediment only.

4.3.4.2 Historical Off-Site Surface Water and Sediment Investigations

As presented in the 2016 HHRA, a total of 47 surface water samples have been collected by AECOM from 38 off-Site locations in the DA from 2014 to 2016. Historical surface water sampling focused on Oakey Creek and the sections of the on-Site drainage channels that extend off-Site to the south, with four locations sampled on Doctor Creek and one location on Westbrook Creek. PFAS concentration ranges are summarised in Table 23.

Table 23 Historical off-Site surface water analytical results summary





PFOS 47 33 <0.02 5.17

PFOA 47 20 <0.02 0.17

PFHxS 7 4 <0.02 3.88

PFHxA 7 5 <0.02 0.65

PFAS were not detected in the primary surface water samples collected from Doctor Creek or Westbrook Creek (PFOS and PFOA concentrations slightly greater than the LOR were reported in one field duplicate sample collected from Westbrook Creek).

The maximum PFOS concentration in surface water (5.17 µg/L) was reported at location SW34A. It is understood that this location is a private dam and not connected to waterways used for recreational, stock watering or irrigation purposes. The greatest magnitude PFOS concentrations were otherwise typically reported at locations on drainage channel 1 and drainage channel 2.

A total of 60 primary off-Site sediment samples have characterised sediments in the DA at 46 locations. Sediment sampling focused on Oakey Creek and the sections of the on-Site drainage channels that extend off-Site to the south, with five locations sampled on Doctor Creek and no locations on Westbrook Creek (as Westbrook Creek does not receive direct discharge of surface water drainage from the Site). Sediment samples were typically co-located with surface water samples. Concentration ranges are summarised in Table 24.

Table 24 Historical off-Site sediment analytical results summary





PFOS 60 46 <0.0005 0.492

PFOA 60 15 <0.0005 0.0079

PFHxS 6 3 <0.0002 0.0548

PFHxA 6 1 <0.0002 0.0097

PFOS was detected in sediment samples collected from Doctor Creek, but at lower magnitude concentrations than in sediment samples collected from Oakey Creek. The greatest magnitude PFOS and PFOA concentrations were reported in sediment at locations on drainage channel 2.

The maximum PFHxS and PFHxA concentrations in sediment were reported at location SW34A. As noted above, it is understood that this location is a private dam and not connected to waterways used for recreational, stock watering or irrigation purposes.



50

Historical off-Site pore water samples were extracted from eight of the above sediment samples for analysis from 2015 to 2016. Concentration ranges are summarised in Table 25.

Table 25 Historical off-Site sediment pore water analytical results summary





PFOS 8 7 <0.01 3.1

PFOA 8 5 <0.01 0.18

PFHxS 4 3 <0.01 0.75

PFHxA 4 2 <0.02 0.23

Pore water concentrations were generally consistent with the order of magnitude of surface water concentrations reported at the same locations.

The historical data indicate that surface drainage channels may be both:

a secondary source of PFAS via remobilisation/leaching from sediments in the drains that were historically impacted during the period of AFFF use on-Site

an ongoing mechanism for transporting PFAS in surface water off-Site to Oakey Creek during flow events.

4.3.4.3 2017 Off-Site Surface Water and Sediment Investigations

The following types of sampling were conducted during the 2017 Stage 2C EI:

Surface water was sampled from all four drainage channels on an opportunistic basis following heavy precipitation events. The locations of 11 surface water samples (collected from along the off-Site sections of the drainage channels) are shown on Figure F5, Appendix A. All surface water samples were analysed for the extended PFAS suite.

Sediment samples were collected from the three drainage channels, representing locations that were either close to the Site, at the midpoint between the Site boundary and Oakey Creek, or near Oakey Creek. The locations of 13 soil bores advanced along the off-Site sections of the drainage channels are shown on Figure F5, Appendix A. All sediment samples were analysed for the extended PFAS suite.

Surface water samples were collected from the three local creeks (Oakey Creek, Doctor Creek and Westbrook Creek) and upstream reference location (Cooby Creek Reservoir). The locations of 39 surface water and 38 sediment samples collected from the local creeks are shown in Figure F5, Appendix A. Concentrations of off-Site sediment samples are shown in Figure F5A, Appendix A. Upstream reference location samples collected from Cooby Creek Reservoir are shown in Figure F5B, Appendix A. All surface water and creek sediment samples were analysed for the extended PFAS suite.

Collection of co-located surface water, sediment and aquatic biota samples.

The purpose of sampling stormwater from the drainage channels and surface water from the creeks was to provide a larger data set to better understand temporal variability in PFAS concentrations in surface water in the drainage channels and surface water in local creeks. The purpose of sampling the off-Site sediment (drains) was to understand the vertical and lateral distribution of residual PFAS within the off-Site portion of the drainage channels.

Concentration ranges for all off-Site surface water samples collected during the 2017 Stage 2C EI are summarised in Table 26.



51

Table 26 2017 off-Site surface water (drainage channels and creeks) analytical results summary





PFOS 50 32 <0.01 6.26

PFOA 50 22 <0.02 1.11

PFHxS 50 25 <0.01 0.94

PFHxA 50 26 <0.02 0.57

The maximum PFAS concentrations in all off-Site surface water collected during the 2017 Stage 2C EI were reported at locations on drainage channel 3 (SW57) and drainage channel 1 (SW67). No PFAS concentrations were detected in the surface water samples from Doctor Creek.

The maximum PFOS concentrations in off-Site surface water collected from the local waterways were reported in Oakey Creek, at a location upstream of the weir (0.58 µg/L PFOS at location SW18). PFOS was detected at the LOR at Westbrook Creek (0.01 µg/L PFOS at location SW87), and in two of the seven samples collected from the upstream reference location at Cooby Creek Reservoir (0.07 µg/L PFOS at location SW72, and 0.02 µg/L PFOS at location SW73).

Based on these data, it is considered unlikely that any upstream sources are contributing to PFAS detections in fish tissue, but this cannot be conclusively ruled out, given the detection of PFAS in water samples collected from Cooby Creek Reservoir. However, as Cooby Creek Reservoir is located approximately 20 kilometres north-east and upstream of the Site, surface water data from this source were not considered when evaluating potential human exposures to surface water inside the IA.

Overall the results show the highest PFAS concentrations in surface water present immediately downstream of the outflows of the drainage channels 1, 2 and 3. The concentrations decrease with increased distance from the Site, with a corresponding decrease in the number of PFAS detected.

Concentration ranges for all off-Site sediment samples collected during the 2017 Stage 2C EI are summarised in Table 27.

Table 27 2017 off-Site sediment analytical results summary





PFOS 65 48 <0.0002 1.38

PFOA 65 38 <0.0002 0.56

PFHxS 65 27 <0.0002 0.070

PFHxA 65 30 <0.0002 0.13

The maximum 2017 PFAS concentrations in all off-Site sediment were detected within the vicinity of drainage channel 2 located approximately 80 m south of the base boundary (BH_DC_26A) at a depth of 2 m bgl. High PFOS concentrations were also detected in drainage channel 3 off-Site, just south of the Site boundary and Corfe Road (0.155 mg/kg PFOS from location BH-DC-22 at 2 m bgl).

The maximum PFOS (0.034 mg/kg at SED065), PFOA (0.0013 mg/kg at SED036) and PFHxA (0.0004 mg/kg at SED104) concentrations in off-Site sediment samples collected from the local waterways were detected in Oakey Creek. A sediment sample collected from Doctor Creek reported the maximum concentration of PFHxS (0.0013 mg/kg at SED053).



52

Overall, the results indicate PFAS are consistently present across the main drainage channels off-Site. However, for the purposes of this HHRA, it is considered unlikely that the drainage channels originating from the Site would be used for recreational fishing, boating or swimming; therefore, only surface water and sediment data obtained from the local accessible waterways (Oakey Creek, Doctor Creek and Westbrook Creek) have been adopted in the assessment of human health risks. A total of 48 primary sediment samples and 53 primary surface water samples have been collected from these local waterways during environmental investigations conducted between 2013 and 2017 (refer to Section 4.2.1).

4.4 Biota Sampling Analysis and Results

Off-Site biota investigations from 2016 and 2017 have included the sampling of fruit and vegetables, eggs, fish, yabbies, mussels, crops, pasture, blood serum from livestock, milk from livestock, and rabbits.

An overview of the relevant biota sampling investigations is presented in Section 4.4.1 to Section 4.4.4. Analytical results are presented in Table 10, Table 11 and Table 12, Appendix B.

4.4.1 Historical Biota Investigations

Biota sampling was conducted by AECOM during March and April 2016 to inform the 2016 HHRA. Sample sources and information relevant to this assessment are summarised below:

Fish commonly caught and consumed by recreational anglers in Oakey Creek. Fish samples were also caught from Cooby Creek Reservoir, and upstream of a weir on Oakey Creek, to provide information on the potential for PFAS body burdens in aquatic fauna from up-stream sources.

Wild rabbits caught during a routine pest control cull undertaken by a Defence contractor on the Site. It was considered unlikely that the specimens caught would be representative of animals potentially consumed by people in the DA. Therefore, the rabbit data were not considered further when estimating human intakes of meat in the 2016 HHRA, but were considered in the 2016 ERA.

Fruit and vegetables that had been irrigated with groundwater containing detectable concentrations of PFAS, or which were grown in soil historically irrigated with PFAS contaminated groundwater.

Pasture plants consumed by livestock raised for human consumption. Samples were collected where plants had been irrigated with groundwater containing detectable concentrations of PFAS, or were grown in soil historically irrigated with groundwater containing detectable concentrations of PFAS.

Plants used for production of fibre (cotton). Samples were collected where plants had been irrigated with groundwater containing detectable concentrations of PFAS, or were grown in soil historically irrigated with groundwater containing detectable concentrations of PFAS. It was noted that the tissue of these plants is unlikely to contribute to direct or indirect intakes by humans, as the plants are not grazed by livestock. Therefore, the cotton data was not considered further in the 2016 HHRA.

Blood serum from livestock (cattle and sheep) raised in the DA. Samples of livestock blood serum were collected in 2016 where livestock were supplied with groundwater containing detectable concentrations of PFAS, or consumed plants grown in soil historically irrigated with groundwater containing detectable concentrations of PFAS. Blood serum data were used to estimate PFAS concentrations in muscle tissue consumed by humans in the 2016 HHRA.

Milk from livestock raised in the DA (cattle and sheep). Milk samples were collected in 2016 where livestock were supplied with groundwater containing detectable concentrations of PFAS, or consumed plants grown in soil historically irrigated with groundwater containing detectable concentrations of PFAS. There was no information to suggest that people within the DA consume sheep milk; therefore, these samples were collected to evaluate potential for intake of PFAS by sheep offspring from ingestion of milk. The sheep milk data were not considered further when estimating human intakes of milk in the 2016 HHRA.



53

Eggs from backyard chickens that had consumed groundwater containing detectable concentrations of PFAS and had access to soils historically irrigated with groundwater containing detectable concentrations of PFAS. A total of 35 chicken eggs were collected across four properties in the IA during 2016. No commercial egg production has been identified in the IA.

A summary of the reported historical concentrations of PFOS, PFOA, PFHxS and PFHxA in tissues of these biota is presented in Table 28. Historic blood serum data for humans are discussed separately in Section 7.6.

It is noted that PFOA was not detected above the laboratory LOR, and PFHxA was rarely reported above the LOR, in any of the biota tissue samples collected as part of the 2016 HHRA.

With the exception of one minor PFOS detection (0.0025 mg/kg compared to an LOR of 0.001 mg/kg), PFAS were not detected in the tissue of fish specimens collected from Cooby Creek Reservoir. This indicates that the PFAS body burden in fish collected further downstream of the Cooby Creek Reservoir towards the Site is unlikely to be attributable to potential sources upstream of Cooby Creek Reservoir.

The absence of detectable PFAS in the tissue of fruit (olives, pumpkin, citrus fruit) is consistent with literature summarised by ToxConsult (2016a, 2016b), which indicates that the transfer of PFAS from soil to the edible parts of most plants is low.



54

Table 28 Historical (March to April 2016) biota tissue PFAS analysis summary

Biota description Units Number of samples

PFOS PFOA PFHxS PFHxA

Samples collected within the DA

Fish – Bony Bream, Oakey Creek

mg/kg 15 0.0076 – 0.081 <0.002 – 0.0027 <0.001 – 0.0018 <0.001

Fish – Golden Perch, Oakey Creek

mg/kg 12 0.048 – 0.25 <0.002 <0.001 – 0.0022 <0.001 – 0.001

Fish – Carp, Oakey Creek mg/kg 3 0.041 – 0.069 <0.002 <0.001 <0.001

Rabbit AACO mg/kg 4 0.043 – 0.09 <0.002 <0.005 – 0.0089 <0.001

Celery mg/kg 10 0.0016 – 0.0061 <0.002 <0.001 – 0.0024 <0.001

Silverbeet mg/kg 10 <0.001 <0.002 <0.001 – 0.0024 <0.001

Pumpkin mg/kg 4 <0.001 <0.002 <0.001 <0.001

Olive mg/kg 10 <0.001 <0.002 <0.001 <0.001

Citrus fruit (lime, orange, mandarin, grapefruit)

mg/kg 10 <0.001 <0.002 <0.001 <0.001

Pasture grasses and lucerne mg/kg 40 <0.001 – 0.012 <0.002 <0.001 – 0.015 <0.001 – 0.0063

Cotton (fibre and seed) mg/kg 5 <0.001 <0.002 <0.001 <0.001

Cotton (leaves) mg/kg 10 <0.001 <0.002 <0.001 – 0.0035 <0.001

Chicken eggs mg/kg 35 <0.003 – 0.049 <0.002 <0.003 – 0.022 <0.001

Cow blood serum mg/L 16 0.084 – 0.31 <0.0005 – 0.0014 0.015 – 0.13 <0.0005

Sheep blood serum mg/L 36 0.044 – 0.18 <0.0005 0.0041 – 0.12 <0.0005



55

Biota description Units Number of samples

PFOS PFOA PFHxS PFHxA

Cow milk mg/L 3 <0.001 – 0.0011 <0.0005 <0.0005 <0.0005

Sheep milk mg/L 5 <0.001 – 0.081 <0.0005 <0.0005 – 0.005 <0.0005

Samples collected at upstream reference location

Fish – Goldfish, Cooby Creek Reservoir

mg/kg 3 <0.001 <0.002 <0.001 <0.001

Fish – Eel-tailed Catfish, Cooby Creek Reservoir

mg/kg 2 <0.001 – 0.003 <0.002 <0.001 <0.001

Fish – Golden Perch, Cooby Creek Reservoir

mg/kg 5 <0.001 <0.002 <0.001 <0.001

Notes:

Laboratory LOR were as follows:

PFOS 0.001 mg/kg, 0.001 mg/L

PFOA 0.002 mg/kg, 0.0005 mg/L

PFHxS 0.001 mg/kg, 0.0005 mg/L PFHxA 0.001 mg/kg, 0.0005 mg/L



56

4.4.2 2017 Biota Investigation

Biota sampling to address the data gaps identified in the 2016 HHRA was conducted by AECOM between February and April 2017 (refer to Section 4.1.2). Sample sources are summarised in Table 29 and Table 30 and briefly outlined below.

Fruit and vegetables that had been irrigated with groundwater/surface water containing detectable concentrations of PFAS, or which were grown in soil historically irrigated with PFAS contaminated groundwater and/or inundated with flood water (locations identified based on previous groundwater sampling conducted by AECOM and community survey results). A total of 78 primary fruit and vegetable samples from 15 plant families were collected across 17 properties, to characterise a range of different types of plant produce in the IA. These data are presented in Table 10, Appendix B.

Eggs from chickens, ducks and a goose that had consumed groundwater containing detectable concentrations of PFAS, and/or had access to soils historically irrigated with groundwater or surface water containing detectable concentrations of PFAS and/or inundated with flood water (locations identified based on previous groundwater sampling conducted by AECOM and community survey results). A total of 27 chicken eggs, four duck eggs and one goose egg were collected across 11 properties in the IA. These data are presented in Table 11, Appendix B.

Fish, yabbies and mussels that are commonly caught and consumed by recreational anglers in publicly accessible waterways in the IA. A total of 45 yabbies and one mussel were collected from Oakey Creek and Doctor Creek and 18 fish were collected from Oakey and Westbrook Creeks. Yabbies were not observed in the upstream reference location (Cooby Creek Reservoir) and as fish had been previously sampled from this location in 2016, no further fish sampling was conducted in Cooby Creek Reservoir in 2017. These data are presented in Table 12, Appendix B.

4.4.3 Summary of PFAS Detected in Biota Samples

A summary of the reported concentrations of PFOS, PFOA, PFHxS and PFHxA in biota tissues is presented in Table 29. All samples were analysed for the extended PFAS suite.



57

Table 29 2017 biota tissue PFAS analysis summary

Biota description Units Number of primary samples collected in 2017

PFOS PFHxS PFOA PFHxA

Aquatic Biota - Fish

Bony Bream, Oakey Creek mg/kg 2 0.0037 – 0.16 <0.0005 - 0.0019 <0.0003 <0.0005

European Carp, Oakey Creek mg/kg 2 0.051-0.064 <0.0005 <0.0003 <0.0005

Goldfish, Oakey Creek and Westbrook Creek

mg/kg 2 0.043-0.52 <0.0005- 0.013 <0.0003 <0.0005

Mosquito Fish, Oakey Creek mg/kg 1 0.29 0.0025 <0.0003 <0.0005

Murray River rainbowfish, Westbrook Creek and Oakey Creek

mg/kg 2 0.016-0.38 <0.0005- 0.0053 <0.0003 <0.0005

Purple-Spotted Gudgeon, Westbrook Creek

mg/kg 1 0.083 <0.0005 <0.0003 <0.0005

Spangled Perch, Westbrook Creek and Oakey Creek

mg/kg 8 0.048-1.6 0.0011-0.0076 <0.0003 <0.0005

Aquatic Biota – Yabbies and Mussels

Inland Yabby mg/kg 45 0.00083 - 0.37 0.0006 - 0.031 0.00033 - 0.0036 <0.0005

Floodplain Mussel mg/kg 1 0.00038 <0.0005 <0.0003 <0.0005

Fruit and Vegetables

Alliaceae (onion, shallot) mg/kg 6 <0.001 <0.001 <0.001 <0.001

Amaranthaceae (beetroot and silverbeet)

mg/kg 10 <0.001 <0.001 <0.001 <0.001

Apiaceae (carrot) mg/kg 5 <0.001 <0.001 <0.001 <0.001



58

Biota description Units Number of primary samples collected in 2017


Asteraceae (jerusalem artichoke)

mg/kg 3 <0.001 <0.001 <0.001 <0.001

Brassicaceae (cabbage) mg/kg 2 <0.001 <0.001 <0.001 <0.001

Caricaceae (pawpaw) mg/kg 1 <0.001 <0.001 <0.001 <0.001

Convulvaceae (sweet potato) mg/kg 6 <0.001 <0.001 <0.001 <0.001

Cucurbitaceae (choko, honeydew melon, pumpkin, zucchini)

mg/kg 9 <0.001 * <0.001 * <0.001 <0.001

Fabaceae (bean) mg/kg 2 <0.001 <0.001 <0.001 <0.001

Lythraceae (pomegranate) mg/kg 1 <0.001 <0.001 <0.001 <0.001

Poaceae (bamboo) mg/kg 3 <0.001 <0.001 <0.001 <0.001

Rosaceae (apples, quince) mg/kg 2 <0.001 <0.001 <0.001 <0.001

Rutaceae (orange, lemon, lime, mandarin)

mg/kg 12 <0.001 <0.001 <0.001 <0.001

Solanaceae (capsicum, tomato, cherry tomato, chilli)

mg/kg 12 <0.001 <0.001 <0.001 <0.001

Vitaceae (grape) mg/kg 4 <0.001 <0.001 <0.001 <0.001

Backyard Eggs

Chicken mg/kg 27 0.00051 - 0.15 <0.0005 - 0.045 <0.0003 - 0.0008 <0.0005

Duck mg/kg 4 0.011-0.028 0.0012-0.0095 <0.0003 <0.0005

Goose mg/kg 1 0.015 0.0084 <0.0003 <0.0005

* It is noted that for pumpkin sample AACO-FLH112, the inter-laboratory duplicate sample was reported to have concentrations of PFOS (0.0004 mg/kg) and PFHxS (0.0007 mg/kg) detected at lower

concentrations than the LOR reported by the primary laboratory (<0.001 mg/kg). Because the PFOS+PFHxS concentration in this sample did not exceed the FSANZ (2017a) trigger value for

vegetables (which includes fruiting vegetables), this single detection in the secondary sample was not considered further in the HHRA.



59

4.4.4 Consideration of Biota Samples in the HHRA

The biota targeted for sampling in 2017 are considered to provide a suitable characterisation of commonly grown fruit, vegetables and eggs in the IA, and supplement the biota data collected in 2016. The sampling locations were selected based on information gathered from community surveys (refer to Section 5.1) that aimed to obtain more information about fruit, vegetables, aquatic fauna (fish, mussels and yabbies), and backyard poultry eggs grown within the IA, and potentially exposed to PFAS, that residents may consume on a regular basis. The sample locations were spread throughout the IA to provide representative biota data coverage across the Groundwater Zones. This is summarised in Table 30. A summary of the biota data used to inform this HHRA is presented in Table 31.



60

Table 30 Summary of biota samples collected in 2017 (terrestrial biota discussed by Groundwater Zone identified for the HHRA)

Type of biota samples collected in 2017

Number of biota samples collected

Range of reported PFOS concentrations in tissue sample

Range of reported PFOS concentrations in soil/sediment at the property where biota samples were collected

Range of reported PFOS concentrations in groundwater/ surface water at the property where biota samples were collected

Notes

Groundwater Zone RoIA – Terrestrial Biota

Leafy green vegetables 6

Not Detected <0.0002-0.01 <0.01-0.06*

A total of 15 primary samples were collected from three properties located in Groundwater Zone RoIA, including six leafy vegetables. Results from the Plant PFAS Uptake Study undertaken in 2017 at RAAF Base Williamtown (refer to Section 5.3) have been used to supplement existing data and estimate theoretical plant PFAS uptake based on the maximum PFAS concentrations reported in groundwater in this Groundwater Zone.

Root/tuber vegetables 4

Fruit 5

Chicken eggs 3 0.0012-0.0019 0.003-0.012 0.02*

A total of three backyard chicken eggs were collected from two properties located in Groundwater Zone RoIA. The Chicken Egg PFAS Residue Study (refer to Section 5.2) was conducted in 2017 to provide additional data on the potential for PFAS residues in chicken eggs associated with a range of dietary PFAS intakes.



61






Notes

Groundwater Zone 1 – Terrestrial Biota


Not Detected 0.0011-0.05 <0.01-4.2*

A total of 23 primary fruit and vegetable samples were collected from six properties in Groundwater Zone 1. Only one leafy green vegetable was collected. Results from the Plant PFAS Uptake Study undertaken in 2017 at RAAF Base Williamtown have been used to supplement existing data and estimate theoretical plant PFAS uptake based on the maximum PFAS concentrations reported in groundwater in this Groundwater Zone.


Fruit 15

Chicken Eggs 14 0.0005-0.028 0.0014-0.0056 <0.01-0.5*

A total of 14 backyard chicken eggs were collected from five properties located in Groundwater Zone 1. The Chicken Egg PFAS Residue Study (refer to Section 5.2) was conducted in 2017 to provide additional data on the potential for PFAS residues in chicken eggs associated with a range of dietary PFAS intakes.

Groundwater Zone 2 – Terrestrial Biota


Not Detected 0.0003-0.11 0.1-40*

A total of 40 fruit and vegetable samples were collected from eight properties located in Groundwater Zone 2. Only nine leafy green vegetables were collected. Results from the Plant PFAS Uptake Study undertaken in 2017 at RAAF Williamtown have been used to supplement existing data.


Fruit 23



62






Notes

Chicken Eggs 10 0.016-0.15 0.03-0.07 1.28-12.1*

A total of 10 eggs have been collected from four properties within Groundwater Zone 2. The Chicken Egg PFAS Residue Study (refer to Section 5.2) was conducted in 2017 to provide additional data on the potential for PFAS residues in chicken eggs associated with a range of dietary PFAS intakes.

Entire IA – Aquatic Biota

Yabbies 45 <0.0005 -0.37 <0.0002-0.03 <0.01-0.6 A total of 25 yabby samples were collected from Oakey Creek, and 20 yabby samples from Doctor Creek.

Fish 18 0.0037-1.6 0.0003-0.0114 <0.01-0.6 A total of 14 fish were collected from Oakey Creek, and four fish were collected from Westbrook Creek.

Note:

* Rounded PFOS concentration only. Actual values not reported to maintain confidentiality.



63

Table 31 Summary of biota samples used to inform the HHRA

Groundwater Zone RoIA Groundwater Zone 1 Groundwater Zone 2

Fruit and Vegetables (2016-2017)

CoPC No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

PFOS 3 15 <0.001 <0.001 0 7 33 <0.001 <0.001 0 10 76 <0.001 0.0061 10

PFHxS 3 15 <0.001 <0.001 0 7 33 <0.001 <0.001 0 10 76 <0.001 0.0024 13

PFOA 3 15 <0.001 <0.001 0 7 33 <0.001 <0.001 0 10 76 <0.001 <0.001 0

PFHxA 3 15 <0.001 <0.001 0 7 33 <0.001 <0.001 0 10 76 <0.001 <0.001 0

Backyard Poultry Eggs (2016-2017)

CoPC No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

PFOS 3 13 <0.003 0.0037 5 5 14 0.00051 0.028 14 4 35 0.0066 0.15 35

PFHxS 3 13 <0.0005 <0.003 0 5 14 <0.0005 0.0051 3 4 35 0.0017 0.045 35

PFOA 3 13 <0.0003 <0.003 0 5 14 <0.0003 <0.0003 0 4 35 <0.0003 0.00076 3

PFHxA 3 13 <0.0005 <0.003 0 5 14 <0.0005 <0.0005 0 4 35 <0.0005 <0.001 0



64


Yabbies (2017)

CoPC No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

PFOS 16 34 <0.0005 0.27 15 - - - - - 4 11 0.015 0.37 11

PFHxS 16 34 <0.0005 0.012 11 - - - - - 4 11 0.0006 0.031 11

PFOA 16 34 <0.0003 0.0036 7 - - - - - 4 11 <0.0003 0.0024 10

PFHxA 16 34 <0.0005 <0.0005 0 - - - - - 4 11 <0.0005 <0.0005 0

Fish (2016-2017)

CoPC No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

PFOS 7 36 0.0037 1.6 36 - - - - - 1 12 0.045 0.66 12

PFHxS 7 36 <0.0005 0.0076 4 - - - - - 1 12 <0.001 0.013 10

PFOA 7 36 <0.0003 0.0027 3 - - - - - 1 12 <0.0003 <0.002 0

PFHxA 7 36 <0.0005 <0.001 0 - - - - - 1 12 <0.0005 0.001 1



65


Cow Milk (2016)

CoPC No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns

No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

PFOS - - - - - 2 3 <0.001 0.0011 1 - - - - -

PFHxS - - - - - 2 3 <0.0005 <0.0005 0 - - - - -

PFOA - - - - - 2 3 <0.0005 <0.0005 0 - - - - -

PFHxA - - - - - 2 3 <0.0005 <0.0005 0 - - - - -

Cow Blood Serum (2016)

CoPC No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

PFOS - - - - - 2 16 0.084 0.31 16 - - - - -

PFHxS - - - - - 2 16 0.015 0.13 16 - - - - -

PFOA - - - - - 2 16 <0.0005 0.0014 7 - - - - -

PFHxA - - - - - 2 16 <0.0005 <0.0005 0 - - - - -



66


Sheep Blood Serum (2016)

CoPC No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

No

. L

oca

tio

ns No

. sa

mp

les

Min

(m

g/k

g)

Max

(m

g/k

g)

No

. d

etec

ts

PFOS - - - - - 1 20 0.054 0.12 20 1 16 0.044 0.18 16

PFHxS - - - - - 1 20 0.022 0.072 20 1 16 0.0041 0.12 16

PFOA - - - - - 1 20 <0.0005 <0.0005 0 1 16 <0.0005 <0.0005 0

PFHxA - - - - - 1 20 <0.0005 <0.0005 0 1 16 <0.0005 <0.0005 0

Note: - No samples collected



67

4.5 Other Published Data

In addition to the investigations completed by AECOM in the IA, researchers from the University of Queensland have also recently published data for environmental sampling and analysis completed in the Oakey area (Bräunig et al., 2017). The potential for bioaccumulation of PFAS in grass, various terrestrial animals and animal products was assessed in that paper.

4.5.1 Sample Collection

Bräunig et al. (2017) reported data for 10 PFAS analysed in samples of water, soil, grass, chicken egg yolk, and blood serum of horses, cattle, sheep and humans, collected off-Site in the Oakey area between October 2014 and March 2016, as follows:

Blood serum samples were collected by a private pathology company from 10 residents (six males and four females) living within the Oakey area. All 10 residents were reported to have lived within the DA for at least a decade and use groundwater bores for everyday activities. Of the 10 residents, one person was reported to have consumed groundwater regularly.

Environmental media sampled included groundwater, surface water, livestock drinking water, surface soil (top 10 cm) and grass samples.

Livestock samples included egg yolk and blood serum from cows, sheep and horses.

4.5.2 Analytical Methodology

Bräunig et al. (2017) reported the following analytical methodology:

All samples were extracted according to matrix specific methods and validated for each matrix separately. Isotopic dilution mass spectrometry was used to determine PFAS concentrations.

Water samples were either directly injected onto an LC-MS/MS system or extracted with methanol/NH3. 50 mL of samples were spiked with 13C8-labelled internal standard before undergoing solid phase extraction (SPE).

Dried soil samples were spiked with 13C8-labelled internal standard and extracted twice by sonication. Samples were then neutralised, reduced in volume to 1 mL and cleaned up using a 100 mg BondElut Carbon cartridge.

Homogenised grass samples were spiked with 13C8-labelled internal standard, digested overnight with methanol/NaOH and extracted using ultrasonication. Samples were reduced in volume to 1 mL and cleaned up using a 250 mg BondElut Carbon cartridge.

Water, soil and grass samples were made up to a final volume of 1 mL and spiked with 13C8-PFOA and 13C8-PFOS labelled performance standards before analysis.

Egg yolk was extracted with acetonitrile using liquid-liquid extraction.

Mass labelled internal standards were added to 200 μL of serum and PFAS were extracted with 1.5 mL acetonitrile using ultrasonication, followed by centrifugation. The supernatant was filtered and the sample volume reduced to 200 μL. 5 mM ammonium acetate in water was added to the sample to a final volume of 500 μL.

PFAS were analysed using high performance liquid chromatography (Nexera HPLC, Shimadzu Corp., Kyoto Japan) coupled to a tandem mass spectrometer (QTrap 5500 AB-Sciex, Concord, Ontario, Canada) operating in negative electrospray ionisation mode and multiple reaction monitoring (MRM) mode.

4.5.3 Summary of Results

The ranges of PFOS and PFHxS concentrations reported by Bräunig et al. (2017) compared with ranges of concentrations reported in off-Site samples collected by AECOM and used in this HHRA are presented in Table 32 and Table 33, respectively.



68

Table 32 Comparison of PFOS data

Media Bräunig et al. (2017) range of PFOS concentrations

Range of PFOS concentrations reported in off-Site samples collected by AECOM and considered in this HHRA

Water (ug/L) * <0.17 - 13 <0.01 – 39.8

Soil (mg/kg) 0.002 – 1.692 <0.0002 – 0.276

Grass (mg/kg) 0.002 – 0.068 <0.0003 – 2.1

Eggs (mg/kg) 0.057 – 0.084 (yolk) <0.003 – 0.15 (yolk and white combined)

Cow blood serum - inside DA (mg/L)

0.024 – 1.583 0.084 – 0.35

Cow blood serum - outside DA (mg/L)

0.056 – 0.215 -

Sheep blood serum (mg/L) 0.137 – 0.259 0.044 – 0.26

Horse blood serum (mg/L) 0.043 – 0.129 -

Human blood serum (mg/L) 0.038 – 0.381 -

* Bräunig et al (2017) did not report PFAS concentrations in different water sources separately (i.e. the range of concentrations

was reported for groundwater, surface water and livestock drinking water combined).

Table 33 Comparison of PFHxS data

Media Bräunig et al. (2017) range of PFHxS concentrations

Range of PFHxS concentrations reported in samples collected by AECOM and considered in this HHRA

Water (ug/L) * <0.07 - 6 <0.02 – 15.2

Soil (mg/kg) <0.0001 – 0.074 <0.0002 – 0.0674

Grass (mg/kg) 0.001 – 0.026 <0.0005 – 0.59

Eggs (mg/kg) 0.01 – 0.016 <0.0005 – 0.045 (yolk and white combined)

Cow blood serum - inside DA (mg/L)

0.002 – 0.125 0.015 – 0.13

Cow blood serum - outside DA (mg/L)

0.0005 – 0.018 -

Sheep blood serum (mg/L) 0.032 – 0.129 0.0041 – 0.13

Horse blood serum (mg/L) 0.018 – 0.074 -

Human blood serum (mg/L) 0.039 – 0.214 -

* Bräunig et al (2017) did not report PFAS concentrations in different water sources separately (i.e. the range of concentrations

was reported for groundwater, surface water and livestock drinking water combined).

The concentration ranges of PFOS and PFHxS in water (groundwater, surface water and livestock drinking water), grass, eggs and sheep blood serum samples reported by Bräunig et al. (2017) were within the range of PFOS and PFHxS concentrations in off-Site samples of the same media collected by AECOM and considered in this HHRA.



69

The maximum concentrations of PFOS and PFHxS reported by Bräunig et al. (2017) in soil were greater than the range of PFOS and PFHxS concentrations in off-Site samples of soil collected by AECOM and considered in this HHRA. However, these maximum concentrations were within the range of PFOS and PFHxS concentrations reported in on-Site samples of soil collected by AECOM and considered in this HHRA.

The maximum PFOS concentration reported by Bräunig et al. (2017) in cow blood serum samples obtained from inside the DA was higher than the range of PFOS and PFHxS concentrations in cattle blood serum samples obtained by AECOM to inform this HHRA. These cattle appear to have been sampled from within Groundwater Zone 2, whereas the cattle blood serum samples collected by AECOM were from animals kept within Groundwater Zone 1, and this is likely to explain the difference in results. It is noted that the EPC adopted in this HHRA for cattle blood serum in Groundwater Zone 2 (refer to Section 5.5) was greater than the average concentration reported in Bräunig et al (2017).

Horse and human blood serum samples have not been collected by AECOM to compare with the data reported in Bräunig et al (2017).

4.6 Distribution of PFAS within Different Media

To evaluate the proportions of individual PFAS detectable in environmental media, and to facilitate an assessment of the sensitivity of the HHRA outcomes to the presence of PFAS for which there are currently no available TRV, the following steps were undertaken for all samples where the extended PFAS suite was analysed:

the total detected PFAS concentration was calculated

the percentage of the total detected PFAS concentration represented by each individual PFAS that was detected was calculated.

A summary of the distribution of PFAS within environmental media is provided in Table 34. It is noted that only samples where the full suite was analysed have been considered in this data review, and the calculations have been conducted on the basis of detections only. For PFAS that were only infrequently detected, this may result in overestimates of the proportion of these chemicals. However, this is not considered to significantly affect the percentages calculated for the four PFAS that are assessed quantitatively in the HHRA. Table 34 presents the average percentage of each PFAS and, therefore, the sum of averages for all PFAS would not necessarily equal to 100%.



70

Table 34 Distribution of PFAS in environmental media

CoPC

On

-Sit

e S

oil

On

-Sit

e

Gro

un

dw

ate

r

On

-Sit

e

Su

rfac

e W

ate

r

Off

-Sit

e S

oil

Off

-Sit

e

Sed

ime

nts

Off

-Sit

e

Gro

un

dw

ate

r

Off

-Sit

e

Su

rfac

e W

ate

r

Off

-Sit

e P

ore

Wat

er

Off

-Sit

e F

ruit

and

Ve

g

Bac

kyar

d E

gg

Fis

h

(Her

biv

oro

us)

Fis

h

(Car

niv

oro

us)

Yab

by

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

PFOS 64% 27% 34% 82% 89% 35% 51% 42% 50% 82% 46% 68% 79%

PFHxS 18% 34% 15% 13% 3% 45% 10% 14% 43% 17% 0% 0% 8%

PFOA 3% 4% 6% 1% 4% 1% 9% 2% 0% 0% 0% 0% 1%

PFHxA 5% 10% 5% 1% 0% 4% 10% 10% 0% 0% 0% 0% 0%

10:2 FTS 0% 0% 0% 0% 0% 0% 0% 0% - - - - -

4:2 FTS 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% -

8:2 FTS 0% 1% 8% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

6:2 FTS 0% 2% 5% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

EtFOSA 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% -

EtFOSE 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% -

EtFOSAA 0% 0% 0% 0% 0% 0% 0% 0% - - - - -

MeFOSA 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% -

MeFOSE 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% -

MeFoSAA 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% -



71

CoPC

On

-Sit

e S

oil

On

-Sit

e

Gro

un

dw

ate

r

On

-Sit

e

Su

rfac

e W

ate

r

Off

-Sit

e S

oil

Off

-Sit

e

Sed

ime

nts

Off

-Sit

e

Gro

un

dw

ate

r

Off

-Sit

e

Su

rfac

e W

ate

r

Off

-Sit

e P

ore

Wat

er

Off

-Sit

e F

ruit

and

Ve

g

Bac

kyar

d E

gg

Fis

h

(Her

biv

oro

us)

Fis

h

(Car

niv

oro

us)

Yab

by

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

Average

(%)

PFBA 0% 1% 1% 0% 0% 0% 0% 32% - - - - 0%

PFDS 1% 0% 0% 0% 1% 0% 0% 0% 0% 0% 1% 2% -

PFHpS 1% 2% 0% 1% 0% 1% 0% 0% - - - - -

PFPeA 2% 4% 2% 0% 0% 1% 13% 0% - 0% - 0% 0%

PFPeS 1% 6% 2% 0% 0% 4% 1% 0% - - - - -

PFBS 2% 7% 3% 1% 0% 8% 2% 2% 6% 0% 0% 0% 0%

PFDA 0% 0% 5% 0% 2% 0% 2% 1% 0% 0% 13% 8% 2%

PFDcS 1% - 0% 0% 0% 0% 0% 0% - - - - -

PFDoDA 0% 0% 2% 0% 0% 0% 1% 0% 0% 0% 22% 13% 7%

PFHpA 1% 2% 3% 0% 0% 1% 0% 1% 0% 0% 0% 0% 0%

PFNA 0% 0% 5% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%

FOSA 1% 0% 0% 0% 0% 0% 0% 0% 0% 0% 1% 1% -

PFTeDA 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 10% 5% -

PFTrDA 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 3% 1% -

PFUnDA 0% 0% 3% 0% 0% 0% 0% 0% 0% 0% 3% 2% 1%

- = not analysed in these samples



72

This evaluation yielded the following results:

In backyard poultry eggs:

- PFOS was the most prevalent PFAS, at an average of 82% of the total PFAS concentration reported

- the balance was primarily composed of PFHxS at an average of 17% of the total detected PFAS concentration, respectively

- other PFAS detected included PFOA and PFDoDA, at concentrations marginally above the laboratory LOR

- the remaining PFAS were not detected.

In fruit and vegetables:

- PFAS were not detected in fruit or root/tuber plant samples4, only in leafy green vegetables (celery and silverbeet) sampled in 2016

- PFOS was the most prevalent PFAS, at an average of 50% of the total detected PFAS concentration

- the balance was primarily composed of PFHxS and PFBS at an average of 43% and 6% of the total PFAS concentration, respectively


In fish:

- a wider range of PFAS were detected in fish samples (11 PFAS detected in herbivorous fish samples and 10 PFAS detected in carnivorous fish samples)

- in carnivorous fish samples, PFOS was the most prevalent PFAS, at an average of 68% of the total PFAS concentration

- the balance was primarily composed of PFDoDA, PFDA and PFTeDA at an average of 13%, 8% and 5% of the total PFAS detected respectively

- other PFAS detected in carnivorous fish samples included PFHxS, PFHxA, PFDS, FOSA, PFTrDA and PFUnDA

- in herbivorous fish samples, PFOS was the most prevalent PFAS, at an average of 46% of the total PFAS concentration reported

- the next most prevalent PFAS were PFDoDA, PFDA and PFTeDA, at an average of 22%, 13% and 10% of the total detected PFAS concentration, respectively

- other PFAS detected included PFHxS, PFOA, PFDS, PFNA, FOSA, PFTrDA and PFUnDA at an average of less than 4% of the total detected PFAS concentration

- the remaining PFAS were not detected

- PFAS were not detected in fish samples collected from the upstream location (Cooby Creek Reservoir).

In yabbies:

- PFOS was the most prevalent PFAS, at an average of 79% of the total PFAS concentration

- the balance was primarily composed of PFHxS and PFDoDA at an average of 8% and 7% of the total PFAS concentration, respectively

4 PFAS were not detected in primary samples of fruit. It is noted that for pumpkin sample AACO-FLH112, the inter-laboratory duplicate sample was reported to have concentrations of PFOS (0.0004 mg/kg) and PFHxS (0.0007 mg/kg) detected at lower concentrations than the LOR reported by the primary laboratory (<0.001 mg/kg). Because the PFOS+PFHxS concentration in this sample did not exceed the FSANZ (2017a) trigger value for vegetables (which includes fruiting vegetables), this single detection in the secondary sample was not considered further in the HHRA.



73

- other PFAS detected included PFOA, PFBS, PFDA, PFNA and PFUnDA at an average of less than 2% of the total detected PFAS concentration.

In soil:

- a wider range of PFAS (26 analytes) were detected in on-site soils than in any other environmental media

- PFOS was the most prevalent PFAS, at an average of 64% of the total PFAS concentration reported in on-Site soil samples and an average of 82% of the total PFAS concentration reported in off-Site soil samples

- the balance was primarily composed of PFHxS and PFHxA for the on-Site soils, and PFHxS for the off-Site soils

- other PFAS detected in on-Site soil included PFOA ,10:2 FTS, 4:2 FTS , 8:2 FTS, 6:2 FTS, MeFoSAA, MeFOSA, EtFOSAA, PFBA, PFDS, PFHpS, PFPeA, PFPeS, PFBS, PFDA, PFDcS, PFDoDA , PFHpA, PFNA, FOSA, PFTeDA, PFTrDA and PFUnDA, each at an average of 3% or less of the total detected PFAS concentration

- other PFAS detected in off-Site soil included MeFOSA, MeFoSAA, PFUnDA, EtFOSAA, PFBA, PFDS, PFHpS, PFPeA, PFPeS, PFBS, PFDA, PFDoDA, PFHpA, PFNA, FOSA and PFUnDA, each at an average of 1% or less of the total detected PFAS concentration


In groundwater:

- PFOS and PFHxS were the prevalent PFAS in on and off-Site groundwater. PFOS was reported at 27% and 35% of the total PFAS concentration for on-Site and off-Site groundwater respectively. PFHxS was reported at 34% and 45% of the total PFAS concentration for on- and off-Site groundwater respectively

- the balance was primarily composed of PFHxA, PFOA and PFBS

- other PFAS detected included PFDA, FOSA, 6:2 FtS, 8:2 FTS, PFBA, PFHpS, PFPeA, PFPeS, PFHpA and PFNA


In surface water:

- a wide range of PFAS (21 analytes) were detected in on-Site surface water

- PFOS was the most prevalent PFAS in on and off-Site surface water samples, at an average of 34% and 51% of the total PFAS concentration respectively

- the balance for on-Site surface water was primarily composed of PFHxS, PFOA, PFHxA, 8:2 FTS, 6:2 FTS, PFDA and PFNA

- the balance for off-Site surface water was primarily composed of PFHxS, PFOA, PFHxA, and PFPeA

- other PFAS detected in on- and off-Site surface water were 10:2 FTS, PFTeDA, PFBA, PFDS, PFHpS, PFPeS, PFBS, PFDoDA, PFHpA, FOSA, PFTrDA and PFUnDA.

In sediment:

- PFOS was the most prevalent PFAS in off-Site sediment samples, at an average of 89% of the total PFAS concentration

- the balance for on-Site surface water was primarily composed of PFHxS, PFOA

- other PFAS detected in off-Site sediment were PFDA, PFHxA, PFDS, PFBS, PFDoDA, PFHpA, PFNA and FOSA each at an average of 2% or less of the total detected PFAS concentration

- on-Site sediment samples have not been analysed for the extended suite of PFAS and hence it was not considered appropriate to prepare a similar summary for on-Site sediments.



74

This analysis indicates that the combined concentrations of PFOS and PFHxS (and to a lesser extent, PFOA and PFHxA) typically contribute to at least 85% of the PFAS detected in off-Site environmental media and biota (excluding surface water, pore water and fish samples where the sum of PFOS, PFOA, PFHxS and PFHxA ranged between approximately 47-80% of the detected PFAS). The quantitative assessment of exposure to these four PFAS for which TRV are available is therefore considered to be sufficiently representative of potential risks associated with exposure to all PFAS detected in the environment.

In acknowledgement of the wider range of PFAS detected in surface water and aquatic biota the HHRA sensitivity assessment (refer to Section 8.3) includes consideration of potential exposure to a wider range of PFAS due to consumption of recreationally caught fish (based on the samples relevant to human consumption as identified in Section 5.5.1.1. This has been undertaken by summing the concentrations of perfluoroalkylsulfonic acids, FOSAs, FOSEs and FOSAAs and assessing these as equivalent in toxicity to PFOS, and summing the concentrations of PFCAs, and telomer sulfonic acids and assessing these as equivalent in toxicity to PFOA (except 4:2 telomer sulfonate and 6:2 telomer sulfonate which were assessed combined with PFHxA).

4.7 Selection of PFAS for Quantitative Assessment in the HHRA

As noted earlier in this report, a typical approach adopted in contaminated land risk assessment is to use published generic assessment criteria relevant to the land use being assessed to screen out chemicals that present a negligible risk, thereby allowing CoPC that require quantitative assessment in the HHRA to be identified. This is commonly referred to as a ‘Tier 1’ assessment.

The use of Tier 1 assessment criteria for selection of CoPC is not considered appropriate for this HHRA because PFAS have the potential to bioaccumulate within the food chain, and no nationally endorsed Australian guideline value has been published that is protective of the potential for bioaccumulation via all potential pathways. The identification of PFAS for assessment in the quantitative HHRA was therefore based on the availability of TRV derived in a manner consistent with relevant Australian science policy, for those PFAS detected above the laboratory LOR.

The discussion of the nature and extent of PFAS impacts in biota, soil, surface water and groundwater on- and off-Site presented in the following sections of this report therefore focuses only on PFOS, PFOA, PFHxS and PFHxA.

A wide range of PFAS may be associated with historical use of legacy AFFF, in varying proportions, depending on the source product and the age of environmental impacts. AECOM understands that the current body of international toxicological research is not sufficient to develop TRV for other PFAS in a manner consistent with relevant Australian science policy; however, they have been included in the analysis of select samples for completeness as this may change in the future.

Therefore, the HHRA provides a quantitative assessment of potential risks associated with exposure to PFOS, PFOA, PFHxA and PFHxS. A discussion of the sensitivity of the HHRA outcomes to exposure to other PFAS (where they have been detected in environmental media) is provided in Section 8.0.

4.8 Conceptual Site Model

A CSM is a site-specific qualitative description of the source(s) of contamination, the pathway(s) by which contaminants may migrate through the environmental media, and the populations that may potentially be exposed.

In order for a human receptor to be exposed to a chemical contaminant deriving from a site, a complete exposure pathway must exist. An exposure pathway describes the course a chemical or physical agent takes from the source to the exposed individual and generally includes the following elements (US EPA, 1989):

a source and mechanism of chemical release

a retention or transport medium (or media where chemicals are transferred between media)

a point of potential human contact with the contaminated media



75

an exposure route (e.g. ingestion, inhalation) at the point of exposure.

Where one or more of the above elements is missing, the exposure pathway is considered to be incomplete and there is therefore no direct risk to the receptor.

The CSM for the Site and associated IA considers information available from reports listed in Section 4.1. The CSM is presented graphically in Figure F7 and Figure F7A, Appendix A and summarised in the following sections.

4.8.1 Sources

The 2017 ESA (AECOM, 2017b) lists the following activities on or near the Site which are considered to have resulted in PFAS impacts on soil, sediment, surface water and/or groundwater.

4.8.1.1 Primary Source Areas

The following activities on or near the Site are considered to have resulted in PFAS impacts on soil, sediment, surface water and/or groundwater:

historical fire-fighting training at the former fire training ground

historical fire-fighting training at the former fire station and foam training area

fire-fighting training at the current AFFF storage and decanting area

AFFF use associated with fuel spills at the former fuel compound and refuelling point in F1

AFFF use associated with fuel spills at the hot fuel area concrete pads in A2

discharge of spent AFFF into recovery tanks at C1, S1 and A2

release of AFFF during dispersed sporadic AFFF discharge events or responses to incidents.

There is the potential for precursor compounds to be present in some areas in addition to the known PFAS.

The desktop study (AECOM, 2015a) also identified three key time periods during which PFAS may have been released to the environment:

Between 1977 and 2002/3 – point and diffuse depleting sources associated with the former fire training ground and former fire station and foam training area

1994 to the present – active sources associated with spent recovery AFFF recovery tanks

2004 to the present – active sources associated with the current fire training ground and AFFF storage area.

Based on anecdotal information relating to fire-fighting operations and training regimes, AECOM (2015a) has estimated that up to 1,273,400 L of AFFF concentrate (a mixture of 3M Lightwater and Ansulite – 3% and 6%) may have been discharged at the Site since circa 1970.

4.8.1.2 Secondary Sources

The following secondary sources are considered to have the potential to result in PFAS impacts on soil, sediment, surface water and/or groundwater:

concrete infrastructure that has been in contact with AFFF

surface soil where AFFF was discharged to surface

unsaturated zone soil beneath potential source zones

sediment and soil along the drainage channel network

former trade waste system (including the former waste water treatment plant location to the south of the former landfill along Lorrimer Street)

sediment within Oakey Creek downstream of the discharge points of the drainage channels

farm dams



76

former landfill in Oakey

an off-Site area potentially used for fire-fighting training by non-Defence personnel along the eastern portion of Lorrimer Street.

4.8.2 Potential Human Receptors

Based on currently available information with regard to the current and ongoing use of the Site and the current land uses within the IA, the following human receptors have been identified:

residents within the IA (including adults, children and infants)

recreational users of publicly accessible areas including playing fields and local waterways within the IA

commercial (agricultural) workers at the properties within the IA

on-Site personnel who work at the Site. This is considered to encompass all personnel who undertake training or other operational works at the Site facility. However, for the purposes of this HHRA, it is assumed that relevant Site personnel use personal protective equipment (PPE) during application of foams and fire training exercises and, therefore, occupational exposure from these activities is not considered as part of the HHRA

on-Site intrusive (e.g. involving excavation of soil, etc.) maintenance workers who may conduct infrequent maintenance works on underground services, or non-intrusive maintenance activities at the Site (i.e. personnel who maintain the gardens and grassed areas at the Site). These maintenance workers have not been quantitatively assessed in this HHRA because it is assumed that potential exposure pathways for these workers can be managed by Defence specifying minimum requirements for inclusion in health and safety plans relating to intrusive works on the Site

visitors to the Site who stay for a short period and are not frequently present at the Site (e.g. people who attend training, or short term contractors). Infrequent visitors to the Site have not been assessed quantitatively in this HHRA because it is assumed that the assessment of full-time Site workers is also protective of infrequent visitors.

4.8.3 Existing Exposure Mitigation Measures

Mitigation measures currently in place to reduce exposure to PFAS in the IA include the following:

Provision of an alternative drinking water supply by Defence on a case-by-case basis to residents within the IA who use groundwater for drinking water or domestic purposes. Examples of alternative water supplies that have been provided include facilitation of a town water connection, cleaning and filling of rainwater tanks that have previously been topped up with groundwater, and cleaning and filling of domestic swimming pools that have previously been topped up with groundwater.

Providing – via community meetings and by mail – the precautionary advice that residents within the IA should not drink the groundwater.

The 2016 HHRA and 2017 HHRA Addendum identified the following precautions that could be followed by people living in the Oakey IA to minimise the potential of ongoing PFAS exposure:

Do not use groundwater for drinking water supply within the IA (including water used for cooking).

Avoid or minimise using groundwater for bathing, showering, home swimming, paddling pools and/or sprinkler play in Groundwater Zone 1 and Zone 2.

Restrict consumption of home grown eggs from backyard poultry exposed to water in Groundwater Zone 1 and Zone 2 containing detectable PFAS.

Minimise consumption of the following until additional data can be collected to refine the HHRA:





77







Avoiding or minimise the use of the water for showering/bathing, sprinklers or to fill swimming pools due to the possibility of unintentionally drinking the water.’

It is therefore considered that exposure pathways associated with drinking water, household uses of water or swimming pools are currently unlikely to be complete (while Defence continues to provide water assistance). However, it is possible these exposure pathways may still be complete for some people, as anecdotal evidence from the community surveys indicates that some residents currently use groundwater and surface water on their property (refer to Section 5.1).

4.8.4 Potentially Complete Human Exposure Pathways

When a potentially complete exposure pathway from source to receptor is identified, the next step is to undertake a risk assessment to evaluate the potential risk to health.

The exposure pathways for each receptor have been identified as follows:

residential – activities that typically occur within the boundaries of a residential property, such as eating, drinking, bathing, cleaning, gardening, backyard recreation including swimming in pools and pet care

recreational – activities that typically occur in publicly accessible recreation areas, such as sport at playing fields and boating, fishing (including consumption of fish that are caught) and swimming in local waterways

commercial agriculture workers – activities that an employee at a commercial agricultural enterprise may undertake during a work day such as irrigation, animal care, land management (e.g. cultivation or excavation of soils). In addition, it is considered likely that where a commercial worker is employed for farm related purposes that they and their families (including children) would consume produce from the farm

on-Site commercial worker – incidental exposure to soils by an office worker at the Site, either during outdoor activities or movement of dust indoors. It is assumed that the assessment of full-time Site workers is also protective of infrequent visitors.

In addition to the above pathways, it is noted that there is the potential for abstracted water to be used in the future for commercial or residential aquaculture, and that this is a protected environmental value under the Environmental Protection Act 1994. Because this pathway has not been identified to currently be occurring, it has been assessed separately in the uncertainty evaluation section of this report (Section 8.0).

It is noted that the dermal permeability of PFAS is considered to be very low. Nevertheless, dermal exposure pathways have been included in the HHRA for completeness and to provide information regarding relative exposures via this pathway compared to ingestion.

A review was undertaken of the commercial agriculture operations identified at properties in the IA with detectable PFAS in groundwater extraction bores:

The western portion of the Site is currently leased for cotton production purposes.



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The commercial agriculture operations identified in Groundwater Zone 2 included cattle and sheep (used for meat production), horses (understood to be used for show and training, but not for meat production) and grain crops.

The commercial agricultural operations identified in Groundwater Zone 1 included sheep and cattle (used for meat production) and olive production.

The commercial agricultural operations identified in Groundwater Zone RoIA included cattle and sheep (used for meat production), dairy and grain crops.

No commercial agricultural vegetable or egg production operations were identified in the IA.

Grain crops, cotton and olives are considered likely to be sent off-property for processing and are therefore unlikely to be directly consumed by commercial agriculture workers working at these properties. Dairy and livestock meat production is therefore the main type of commercial food production operation identified in the IA that may be relevant to dietary intakes of commercial workers and their families.

Pathways that are considered to be potentially complete based on currently available information have been summarised in Table 35 for residents, Table 36 for recreational users of publicly accessible areas, Table 37 for commercial agriculture workers and Table 38 for on-Site personnel, along with a reference to the relevant equations included in Appendix G that will be used in the exposure assessment. For a number of pathways that are considered to be potentially complete, management measures are currently in place to reduce the potential for exposure via this pathway. Management measures include precautions to minimise exposure as recommended by Queensland Government (consistent with the 2016 HHRA and 2017 HHRA Addendum), and provision of an alternative water supply to eligible stakeholders by Defence. The identified potentially complete pathways were assessed quantitatively in the HHRA.



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Table 35 Exposure pathway analysis – residents in the IA

Exposure pathway Complete? Comments Equations

Ingestion of groundwater containing detectable concentrations of PFAS used as a source of drinking water supply.

() This exposure pathway was historically complete (a), but is currently being managed through a precautionary recommendation from Defence not to drink the groundwater within the IA, and provision of water assistance to residents on a case-by-case basis. However, this exposure pathway may still be complete for some residents in the IA.

Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by not drinking the impacted water or using it to prepare food.

Appendix G1 – Ingestion of potable water

Dermal contact with and incidental ingestion of groundwater containing detectable concentrations of PFAS used for indoor domestic activities.

() It is understood that residents use groundwater for household purposes including showering, laundering, cleaning, food preparation and washing dishes. This exposure pathway is currently being managed through provision of water assistance to residents on a case-by-case basis, which in some cases has extended to provision of an alternative water supply to laundries and kitchens. However, this exposure pathway may still be complete for some residents in the IA.

Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by avoiding or minimising the use of the water for showering/bathing due to the possibility of unintentionally drinking the impacted water.

Appendix G5 – Dermal contact with water and incidental ingestion of water during showering/bathing

Appendix G6 – Dermal contact with water during domestic food and drink preparation and clean–up

Appendix G7 – Dermal contact with water during domestic laundry and clothes care

Appendix G8 – Dermal contact with water during household cleaning activities

Appendix G22 – Dermal contact and incidental ingestion of surface residues from washing floors and clothes



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Dermal contact with and incidental ingestion of groundwater containing detectable concentrations of PFAS used for outdoor domestic and recreational activities (e.g. irrigation of gardens, washing animals or vehicles, playing in a sprinkler).

() Based on currently available information, residents are continuing to use groundwater for household irrigation purposes and other domestic non-potable uses such as washing vehicles and animals.

Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by avoiding or minimising the use of the water for sprinklers due to the possibility of unintentionally drinking the impacted water.

Appendix G13 – Dermal contact with water and incidental ingestion during sprinkler play

Appendix G14 – Dermal contact with water and incidental ingestion during washing animals

Appendix G15 – Dermal contact with water and incidental ingestion during the washing of vehicles

Appendix G16 – Dermal contact with water and incidental ingestion during irrigation activities

Appendix G23 – Dermal contact and incidental ingestion of surface residues after dog washing

Dermal contact with and incidental ingestion of groundwater containing detectable concentrations of PFAS used to fill residential swimming pools and/or paddling pools.

() This exposure pathway was historically complete but is currently being managed through provision of alternative water assistance on a case-by-case basis to residents within the IA who have used groundwater to fill residential swimming pools. Examples of water assistance that has been provided include cleaning and filling of domestic swimming pools that have previously been topped up with groundwater. However, this exposure pathway may still be complete for some residents in the IA.

Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by avoiding or minimising the use of the water to fill swimming pools due to the possibility of unintentionally drinking the impacted water.

Appendix G11 – Dermal contact with water and incidental ingestion during swimming in domestic pools



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Dermal contact with and incidental ingestion of surface soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation purposes.

There is potential that soils may contains PFAS where groundwater containing detectable concentrations of PFAS has been used for domestic irrigation purposes; therefore soil related exposure pathways may be complete for residents.

Incidental ingestion and inhalation are considered to be the primary pathways by which people could be exposed to PFAS in dust. Where dust settles on rooftops and washes into rainwater tanks over a long period of time, there is also a potential for a small amount of PFAS to be transferred to tank water. Where requested by residents Defence has undertaken rain water tank emptying, cleaning and refilling with town water. This would mitigate this pathway where completed. It is also noted that where first flush diverters have been fitted to rainwater tanks (as recommended by enHealth and required within the Queensland Development Code) these will divert the initial 20L flow from a roof (which may contain dust, bird droppings and organic material) and prevent it from being taken into the tank.

Appendix G2 – Incidental ingestion of soil

Appendix G3 – Dermal contact with soil

Inhalation of surface soil derived dust where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation purposes.

Appendix G4 – Inhalation of dust



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Ingestion of PFAS accumulated in home-grown produce irrigated with groundwater (or surface water) containing detectable concentrations of PFAS. PFAS may accumulate in plant produce via:

Uptake of contaminated groundwater (or surface water) containing detectable concentrations of PFAS used for irrigation.

Uptake of PFAS from soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation.

PFAS may also be present on the above-ground surfaces of produce due to adherence from irrigation water or wind-blown dust.

() It is understood that a number of residents in the area surrounding the Site use extracted groundwater for irrigation of fruit/vegetable gardens.

Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by not consuming food products grown or produced using, or in, contaminated water.

Appendix G17 – Plant uptake and subsequent ingestion of plant produce (fruit and vegetables)

Incidental ingestion of PFAS in soil adhered to home-grown produce. PFAS may be present in soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation.

Based on the potential for the use of groundwater containing detectable concentrations of PFAS for irrigation purposes, there is potential for incidental ingestion of soil containing PFAS adhered to home-grown produce.

Appendix G2 – Incidental ingestion of soil



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Ingestion of PFAS accumulated in home-grown livestock and animal produce (for example, meat or eggs). PFAS may accumulate in animal produce via:

Direct ingestion of groundwater (or surface water) containing detectable concentrations of PFAS used for stock watering.

Direct ingestion of soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation.

Ingestion of plant produce (commercial or home grown) that may have accumulated PFAS due to the current or historic use of groundwater (or surface water) containing detectable concentrations of PFAS for irrigation and/or transfer of PFAS to soil.

Intake of milk if mothers have been exposed via the identified pathways.

() It is understood that a number of residents in the IA use groundwater for livestock and plant watering purposes, and that these residents may consume their livestock. Within the IA, livestock identified as being supplied with groundwater include chicken for egg production and sheep and cattle for red meat production.

Properties raising chickens and eggs for human consumption and cattle for milk production have been identified in the IA.

The ingestion of milk and red meat from cattle and eggs from chickens has been included in the HHRA to provide information as to potential PFAS intakes via these pathways.

The assessment of ingestion of home grown red meat has been based on PFAS concentrations estimated in muscle tissue. It is noted that higher concentrations of PFAS are likely to be encountered in offal such as liver and kidneys compared to muscle tissue, and therefore the conclusions of this HHRA in regard to consumption of red meat also apply to consumption of offal.


Appendix G19 – Ingestion of milk from livestock

Appendix G20 – Ingestion of meat from livestock

Appendix G21 – Ingestion of chicken eggs

Notes: a. It is noted that this exposure pathway is currently being mitigated by supply of drinking water by Defence. However it has been reported that the Toowoomba Regional Council (TRC) previously

extracted groundwater from near the Site to supplement the town water supply. AECOM understands that TRC no longer extracts groundwater from the Oakey area for use in the domestic supply (TRC, 2014) and thus this exposure pathway is not considered to be currently complete.

= Pathway considered to be potentially complete for this receptor. () = Pathway considered to be potentially complete for this receptor; however, management measures are currently in place to reduce the potential for exposure via this pathway. Management measures include precautions to minimise exposure recommended by Queensland Government (consistent with the 2016 HHRA and 2017 HHRA Addendum), and provision of an alternative water supply to eligible stakeholders by Defence.



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Table 36 Exposure pathway analysis – recreational users of publicly accessible areas in the IA


Dermal contact, incidental ingestion and dust inhalation from surface soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation purposes at playing fields.

It has been assumed that there is potential for soil impacts to be present where contaminated groundwater has been used for irrigation purposes (i.e. as a result of irrigation of grass at parks and sporting grounds).

Appendix G2- Incidental ingestion of soil

Appendix G3 Dermal contact with soil

Direct contact with groundwater used for irrigation of playing fields.

() Considered unlikely that sporting activities would be routinely undertaken during or immediately after irrigation. Not assessed in this HHRA for recreational users of publicly accessible areas. It is noted that potential exposure via this pathway to workers who undertake irrigation activities has been assessed for the commercial agriculture worker scenario.

Dermal contact with and incidental ingestion of sediment and surface water during recreational activities (e.g., swimming, boating and fishing) in waterways which are hydraulically connected to the Site.

PFAS have been reported to be present in sediment and surface water within local waterways. Thus there is potential for this exposure pathway to be complete for recreational users of Oakey Creek, Westbrook Creek and Doctor Creek.

Appendix G9 Dermal contact with water and sediment and incidental ingestion of water and sediment during fishing

Appendix G10 Dermal contact with water and sediment and incidental ingestion of water and sediment during boating

Appendix G12 Dermal contact with water and sediment and incidental ingestion of water and sediment during swimming in creeks and other surface water bodies



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Ingestion of PFAS accumulated in aquatic organisms collected from waterways which may be connected to the Site. PFAS may accumulate in aquatic organisms via:

direct contact with surface water and/or sediment

secondary ingestion of lower trophic order organisms that may have accumulated PFAS in their tissue via direct contact with surface water and/or sediment.

PFAS have been reported to be present in Oakey Creek, Westbrook Creek and Doctor Creek (refer to discussion in Section 5.5.1.1). Therefore there is potential for ingestion of PFAS accumulated in aquatic organisms.

The potential for recreational users ingest fish caught from future potential aquaculture farms has been assessed as part of the uncertainty assessment (refer to Section 8.1).

Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by not consuming food products including fish grown or produced using, or in, contaminated water.

Appendix G18 – Ingestion of fish and Yabbies

Notes:

= Pathway considered to be potentially complete for this receptor.

() = Pathway considered to be potentially complete for this receptor, however the likely timing and frequency are considered to reduce the potential for exposure via this pathway.



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Table 37 Exposure pathway analysis – commercial agriculture workers in the IA


Ingestion of PFAS accumulated in produce irrigated with groundwater (or surface water) containing detectable concentrations of PFAS. PFAS may accumulate in plant produce via:

uptake of groundwater (or surface water) containing detectable concentrations of PFAS used for irrigation

uptake of PFAS from soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation.

PFAS may also be present on the aboveground surface of produce due to adherence from irrigation water or wind-blown dust.

No commercial vegetable production was identified in the IA in association with groundwater extraction bores with detectable PFAS.

Incidental ingestion of PFAS in soil adhered to produce. PFAS may be present in soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation.

No commercial vegetable production was identified in the IA in association with groundwater extraction bores with detectable PFAS.



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Ingestion of PFAS accumulated in livestock and animal produce (for example, meat or eggs). PFAS may accumulate in animal produce via:

direct ingestion of groundwater (or surface water) containing detectable concentrations of PFAS used for stock watering

direct ingestion of soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation

ingestion of plant produce (commercial or home grown) that may have accumulated PFAS due to the current or historic use of groundwater (or surface water) containing detectable concentrations of PFAS for irrigation.

() Commercial sheep and cattle production has been identified in the IA in all three Groundwater Zones in association with groundwater extraction bores with detectable PFAS. Commercial dairy operations have been identified in Groundwater Zone RoIA.

No commercial agricultural vegetable or egg production operations were identified in association with the properties with detectable PFAS in groundwater extraction bores in the IA.


Appendix G19 – Ingestion of milk from livestock

Appendix G20 Ingestion of red meat from livestock

Dermal contact with and incidental ingestion of groundwater (or surface water) containing detectable concentrations of PFAS extracted for commercial (agricultural) use.

This exposure pathway is considered likely to be complete for these people.

Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by avoiding or minimising the use of the water for sprinklers due to the possibility of unintentionally drinking the water.

Appendix G16 Dermal contact with water and incidental ingestion during irrigation activities



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Dermal contact with and incidental ingestion of surface soil where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation purposes.


Queensland Health has advised that in areas where contamination of water has been identified, human exposure can be minimised by avoiding or minimising the use of the water for sprinklers due to the possibility of unintentionally drinking the water.

Appendix G2 Incidental ingestion of soil


Inhalation of surface soil derived dust where groundwater (or surface water) containing detectable concentrations of PFAS is currently or was historically used for irrigation purposes.


Appendix G4 Inhalation of dust

Notes: = Pathway considered to be potentially complete for this receptor; () = Pathway considered to be potentially complete for this receptor; however, management measures are currently in place to reduce the potential for exposure via this pathway. Management measures include precautions to minimise exposure recommended in the 2016 HHRA and 2017 HHRA Addendum. = pathway considered to be incomplete for this receptor.



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Table 38 Exposure pathway analysis – on-Site personnel


Site personnel

Dermal contact with and incidental ingestion of soils containing detectable concentrations of PFAS at the Site.

This pathway is considered to be potentially complete for these people. Site personnel may make use of outdoor areas for activities such as training exercises or meal breaks. During such activities direct access to exposed surface soil may occur.

Appendix G2 Incidental ingestion of soil


Inhalation of dust generated from soils containing detectable concentrations of PFAS at the Site.

Dust may be generated by wind erosion of exposed surface soils and atmospheric dispersion across the Site.

Appendix G4 Inhalation of dust

Dermal contact with and incidental ingestion of groundwater containing detectable concentrations of PFAS.

This exposure pathway was historically complete (including use of groundwater to fill the swimming pool) but is currently being managed such that no groundwater extraction is occurring at the Site.

Not assessed

Site maintenance workers (both intrusive and non-intrusive)

Dermal contact with and incidental ingestion of soils containing detectable concentrations of PFAS at the Site.

() There is potential that maintenance (both intrusive and non-intrusive) works may be conducted in areas where soils containing detectable concentrations of PFAS are present.

It is assumed that potential exposure pathways for intrusive maintenance workers on the Site (including exposure to other sources of environmental contamination) can be managed by specifying minimum requirements for inclusion in health and safety plans for intrusive works to be undertaken on the Site. Therefore, intrusive maintenance workers have not been quantitatively assessed in the HHRA.

Not assessed



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Inhalation of dust generated from soils containing detectable concentrations of PFAS at the Site.

() Dust may be generated by wind erosion of exposed surface soils and atmospheric dispersion across the Site.

It is assumed that potential exposure pathways for intrusive maintenance workers on the Site (including exposure to other sources of environmental contamination) can be managed by specifying minimum requirements for inclusion in health and safety plans for intrusive works to be undertaken on the Site. Therefore, intrusive maintenance workers have not been quantitatively assessed in the HHRA.

Not assessed

Dermal contact with and incidental ingestion of groundwater containing detectable concentrations of PFAS.

There is currently no extraction of groundwater occurring at the Site, and depth to groundwater is in excess of 2 m bgl; therefore, direct contact with groundwater at the Site during routine excavations is not considered likely to occur for on-Site personnel.

Not assessed

Dermal contact with and incidental ingestion of surface water and sediment containing detectable concentrations of PFAS within drainage channels.

() There is potential for intrusive works to be associated with (or in the vicinity of) drainage channels present at the Site. Thus there is potential for this exposure pathway to be complete for intrusive maintenance workers.

It is assumed that potential exposure pathways for intrusive maintenance workers on the Site (including exposure to other sources of environmental contamination) can be managed by specifying minimum requirements for inclusion in health and safety plans for intrusive works to be undertaken on the Site. Therefore, these receptors have not been quantitatively assessed in the HHRA.

Not assessed

Note:

= Pathway considered incomplete for this receptor

= Pathway considered to be potentially complete for this receptor

() = Pathway considered to be potentially complete for this receptor, however it is considered that management measures can mitigate the potential for exposure via this pathway.



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5.0 Exposure Assessment Exposure assessment involves the estimation of magnitude, frequency, extent and duration of exposure to Site contamination (enHealth, 2012b).

The key elements of exposure assessment in the context of contamination related risk assessments are:

analysis of contaminant releases

identification of potential exposure pathways

estimation of exposure concentrations for each pathway

evaluation of uncertainties.

5.1 Human Behavioural Exposure Assumptions

5.1.1 Typical vs. Upper Range Exposure

Human behavioural patterns vary from one individual to another. To account for this while remaining protective of general population exposures, this HHRA considers a range of exposure assumptions:

A ‘typical’ exposure was based on mean or median parameters for the general population. The use of typical values was intended to capture the typical and average exposure for the majority of the population based on a combination of ‘common sense’ professional judgement and published values regarding exposure frequency and potential PFAS ingestion. It is anticipated that the assessment of the typical scenario will be applicable to the majority of the population.

Upper range exposure was based on reasonable maximum exposure parameters. The use of upper values was intended to:

- be representative of a reasonable maximum exposure (RME)

- capture receptors who undertake activities at a higher frequency or ingest more than the average person

- provide an estimate of exposure that is reflective of the upper/high end of the scale of potential exposure. It is considered that the exposure frequency and quantity assumed by the upper scenario will only apply to small percentage of the population.

It should be noted that both the typical and upper range exposure assumptions have been coupled with maximum EPC for soil, groundwater, sediment, surface water, cow milk and red meat, and as a result the HHRA outcomes are considered to be conservative – overestimating, rather than underestimating, the risks to human health. In particular, the combination of upper exposure assumptions (which were based on high exposure frequency and/or high exposure quantity) and maximum EPC is considered likely to be highly conservative.

Human exposure parameters adopted for the HHRA, their source and justification are presented in Appendix F. The information used to select these parameters included surveys of the community, field observations and published data from Australian and international sources, as discussed in the following sections of this report.

5.1.2 Sources of Exposure Assumptions

5.1.2.1 Site Specific Information from Community Surveys

Three surveys of the Oakey community have been conducted by Defence and used to generate data for this HHRA:

Survey 1 (referred to as the ‘water use survey’) was first distributed on 7 August 2014. Survey 1 focused on identifying whether people had access to more than one source of water, and what activities they used groundwater for at their property. A total of 127 responses to the survey were received by Defence. Of these, 44% of respondents indicated that they had access to groundwater via an extraction bore at their property. More than 75% of respondents had access



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to rainwater tanks or town water at their property. A total of 21% of respondents indicated that they used groundwater for drinking purposes, 42% indicated that they used groundwater for other household purposes and 21% indicated that they used groundwater to fill swimming pools. Livestock water supply and irrigating vegetable gardens were the most frequently reported uses of groundwater (58% and 72% of respondents, respectively).

Survey 2 (referred to as the ‘community survey’) was first distributed on 25 February 2016, and was specifically used to identity potentially complete exposure pathways in the CSM. A total of 202 responses to Survey 2 were received. The community survey questions were specifically developed to allow multiple exposure pathways to be identified and assessed, and considered the nature and frequency of potential exposure scenarios. Key questions from community survey included:

- how bore water is currently used at the property

- what types of plants are irrigated with groundwater

- what types of livestock are watered with groundwater

- how often the respondents eat eggs from chickens watered with groundwater

- local waterway recreational usage

- how often respondents use the local waterways for fishing and eat what they catch.

Survey 3 (referred to as the ‘data gap community survey’) was first distributed on 21 February 2017 via email to more than 700 community members (approximately 300 within the IA). Hard copy versions of the survey were also distributed on 25 February 2017 via letterbox distribution to approximately 2,200 properties and businesses within the IA. An electronic copy of the survey was made available on the Site Environmental Investigation project website on 21 February 2017. The official end date of the survey was published as 30 May 2017. The survey was specifically designed to assist in addressing data gaps identified in the 2016 HHRA. The community survey was undertaken to obtain more information about how people in the IA would typically use their land to grow plant produce and livestock, together with quantities consumed and typical frequency. The questions in the survey sought to understand how people in the IA would typically use their land to grow produce and livestock, together with how much of this produce, and how often they would typically consume it. The survey asked respondents to answer based on overall dietary habits and land use practices prior to mid-2014 when the precautionary recommendation was issued for residents not to drink groundwater in the IA. Dietary habits and land use practices prior to mid-2014 were considered more representative of typical activities undertaken by people living and working in the IA and how land might be used in the future if there were no restrictions. The survey findings considered of relevance to the HHRA are discussed below and presented in Appendix E:

- A total of 116 responses to Survey 3 were received, and of these 115 responses were reported to be for unique addresses in the IA (i.e. only two surveys were submitted by individuals living at the same address). Based on the 116 survey responses, half of the respondents (50%, n = 58) indicated that they had previously used bore water and 17% (n = 20) used surface water on the property prior to mid-2014. Of the respondents who indicated they previously used bore water, 62% (n = 36) indicated they had previously grown fruit and vegetables and 28% (n = 16) indicated they irrigated their home fruit or vegetable gardens once or twice a week.

- Less than half the respondents currently use bore water (37%, n = 43) or surface water (9%, n = 11) on their property, following Defence’s precautionary recommendations issued mid-2014. Of the respondents who currently use bore water on their property, 51% (n = 22) indicated they currently grow fruit and vegetables.

- For the respondents currently irrigating vegetable gardens using bore water, the survey results indicate that fruit and leafy green vegetables are most commonly grown, followed by root/tuber vegetables. The plants most commonly reported to be irrigated with groundwater are summarised in Table 39.



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Table 39 Plants reported to be currently irrigated with groundwater in Survey 3 (data gap survey)

Plant Percentage of respondents currently using groundwater for irrigation of this plant

Sample obtained during 2017 biota sampling event

Tomato 23% Yes

Lettuce 11% Yes (silverbeet)

Citrus 15% Yes

Cucumber 12% No

Potato 13% No

Pumpkin 11% Yes

Zucchini 7% Yes

Broccoli 8% No

Cauliflower 7% No

Cabbage 8% Yes

Strawberry 3% No

Stone fruit 8% No

Capsicum 6% Yes

Melon 4% Yes

Radish 4% No

Squash 3% No

Sweet potato 3% Yes

Kale 2% No

Brussels sprout 3% No

Turnip 2% No

Bok choi 0% No

Apple 2% Yes

Chinese cabbage 1% Yes

Lemongrass 0% No

Mustard 1% No

Pear 1% No

Artichoke 1% Yes

Sugarcane 0% No

Percentages based on 116 survey responses.



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During the biota sampling conducted by AECOM in 2017, samples were collected of home grown fruit and vegetables that were in season at the time. It is considered that the plant species targeted for sampling in 2017 provide a suitable supplemental characterisation of some commonly grown fruit and vegetables in the IA. However, it is noted that the results from the community survey indicate that home grown fruit and vegetable production may have decreased in the IA following Defence issuing precautionary advice not to drink groundwater within the IA.

Dietary habits of the respondents were also captured in the survey and were used to refine the exposure assumptions in the HHRA. The proportions of home grown fruit, vegetables, red meat, poultry and eggs in diet are summarised in Table 40.

Table 40 Dietary proportions of home grown produce

Dietary Proportions Percentage of respondents

Proportion of fruit in diet that was home grown or from other producers in the IA

None 47%

Less than 10% of home grown fruits in diet 22%

10-20% of home grown fruits in diet 16%




Proportion of vegetables in diet that was home grown or from other producers in the IA

None 37%

Less than 10% of home grown vegetables in diet 23%

10-20% of home grown vegetables in diet 16%




Proportion of eggs in diet that was home grown or from other producers in the IA

None 59%

Less than 10% of home grown eggs in diet 6%

10-20% of home grown eggs in diet 3%




Proportion of red meat in diet that was home grown or from other producers in the IA

None 73%

Less than 10% of home grown red meat in diet 13%

10-20% of home grown red meat in diet 3%



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Dietary Proportions Percentage of respondents




Proportion of poultry meat in diet that was home grown or from other producers in the IA

None 72%

Less than 10% of home grown poultry meat in diet 16%

10-20% of home grown poultry meat in diet 3%




Proportion of fish, yabbies or mussels in diet that was sourced from local waterways or dams in the IA

None 88%

Less than 10% of fish, yabbies or mussels in diet 5%

10-20% of fish, yabbies or mussels in diet 2%




Note: none and off (no selection) answers were combined. Proportions based on 116 survey responses.

Of the respondents who indicated they used bore water on their property, 45% (n = 26) indicated they previously kept backyard chickens prior to 2014 and consumed the home grown chicken eggs. Currently, a total of 22% (n = 25) of respondents keep backyard chickens and 28% (n = 7) of those respondents indicate that they use bore water and 4% (n = 1) use surface water to water their chickens.

A total of 28% (n = 33) of respondents indicate that they use local waterways for fishing. Of these respondents, 91% (n = 30) indicated they use Oakey Creek, 18% (n = 6) use Westbrook Creek and Doctor Creek and 42% (n = 14) use Cooby Creek Reservoir as recreational fishing locations. Currently, 39% (n = 13) of the respondents fish once a year in local waterways and 30% (n = 10) of the respondents indicated that the duration of a fishing trip is approximately two hours.

As discussed in Section 1.2, the 2017 biota sample locations were based on the information obtained from Survey 3 (data gap survey). Fruit and vegetable sampling locations were selected from respondents who indicated that they currently used groundwater or surface water for irrigation of their home grown produce. Similarly, backyard chicken egg sampling locations were selected from respondents who indicated that their chickens currently drink from bore water or surface water. Only residents who had indicated that they would be willing to participate in the biota sampling program were contacted. Further, additional biota sampling locations were based on discussions with residents who had indicated that their property had historically been inundated with floodwater and currently grow fruit and vegetables and/or chickens on their properties.



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5.1.2.2 Published Data

The information derived from the surveys has been further supplemented by quantitative estimates for human behavioural exposure assumptions obtained from the following recognised Australian and international resources:

ASC NEPM 2013

Australian Exposure Factor Guide. Department of Health and Aging (enHealth, 2012a)

Environmental Health Risk Assessment, Guidelines for Assessing Human Health Risks from Environmental Hazards. Department of Health and Aging, 2012 Update (enHealth, 2012b)

Australian Health Survey 2011-13, National Nutrition and Physical Activity Survey (Australian Bureau of Statistics, 2014)

Sport And Recreation: A Statistical Overview, Australia (Australian Bureau of Statistics, 2009)

Children's Participation in Cultural and Leisure Activities (Australian Bureau of Statistics, 2006)

National Nutrition Survey Foods Eaten Australia (Australian Bureau of Statistics, 1995)

Australian Dietary Guidelines (NHMRC, 2013a)

Exposure Factors Handbook 2011 Edition (Final) (US EPA, 2011)

Child-Specific Exposure Factors Handbook EPA/600/R-06/096F September 2008 United States Environmental Protection Agency, Washington, DC (US EPA, 2008)

Descriptive Statistics Tables from a Detailed Analysis of the National Human Activity Pattern Survey (NHAPS) Data (US EPA, 1996)

Risk Assessment Guidance for Superfund Volume I – Human Health Evaluation Manual Part A. United States Environmental Protection Agency Office of Emergency and Remedial Response. Washington DC, Revised December 1989; and associated updates (US EPA, 1989)

Updated technical background to the CLEA model, SC050021/SR3 (Environment Agency, 2009)

Guidelines for the Assessment and Management of Petroleum Hydrocarbon Contaminated Sites in New Zealand Appendix 5A Irrigation Water Criteria (New Zealand Ministry for the Environment, 1999).

Where specific guidance is not available from the above or other literature sources, conservative estimates for exposure parameters were adopted based on professional judgement.

5.1.3 General Exposure Parameters

In Australia it is generally assumed for the purpose of screening risk assessments and setting guideline values that the most sensitive individual is the 2–3 year old child (enHealth, 2012b; ASC NEPM 2013). In some scenarios (i.e. commercial settings) children are not likely to be frequently present and therefore adults are also considered separately.

Children differ from adults in a range of behavioural and physiological parameters that may need to be taken into account in the risk characterisation phase of risk assessments (e.g. hand-to-mouth activities for soils, higher respiration rates per unit body weight, increased gastrointestinal absorption of some substances).

The HHRA adopts the approach recommended in ASC NEPM (2013), Schedule B7, which states that ‘young child residents and recreational receptors, while assessed on the basis of parameters relevant to 2−3 year old children, have been taken to be representative of children aged between 0 and 6 years of age who live within the same dwelling or visit the same open space area for their entire childhood’.

For consistency with the approach adopted in ASC NEPM (2013), older children (i.e. more than five years old) are not modelled separately to adults. Adults are considered to be the primary group engaged in many of the activities identified as having potentially complete exposure pathways (e.g. food preparation, household cleaning, laundry, washing animals or vehicles, irrigating gardens).



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Both infants and children in the age range 05 years old have been assessed on the basis of parameters relevant to 2−3 year old children on the basis of the following assumptions:

In accordance with enHealth (2012b), the adoption of parameters based on a 23 year old child was considered representative of the most sensitive age range within this group.

Infants (01 year old) spend less time outdoors and are not likely to engage in many of the associated activities identified as having potentially complete exposure pathways.

In relation to food ingestion intakes, although infants have approximately 50% of the body weight of a 23 year old, they typically have negligible intake of solid foods until six months of age (NHMRC [2013b] Infant Feeding Guidelines recommend introducing solid foods at six months of age), and therefore approximately 50% of the exposure frequency of a 23 year old. Australian data for food intakes for 01 year old infants are generally not available; however, data from US studies typically indicate comparable or lower food intake rates compared to 23 year old children. Therefore, assessing the food intakes for a 01 year old infant based on parameters for a 23 year old child is considered conservatively protective.

Although infants have a higher skin surface area to body weight ratio than 23 year old children, infants are unlikely to participate in many of the identified potential dermal exposure pathways.

5.1.4 Food Ingestion Rates

Ingestion rates adopted in the HHRA for red meat, eggs, fish and yabbies are presented in Appendix F. The ingestion rates were selected based on publicly available Australian food consumption data and professional judgement as follows:

The Australian Bureau of Statistics (ABS) 2011-2012 National Nutrition and Physical Activity Survey (NNPAS) and FSANZ (2017a) were adopted as the primary source of ingestion rates.

Professional judgement and information from community surveys was applied to data from the NNPAS to reflect realistic ingestion rates across the range of foods included in the cumulative pathways considered by the HHRA.

The Nutrition Australia (2013) Australian Dietary Guidelines were referenced to inform adjustments to the NNPAS ingestion rates and provide context for the adopted ingestion rates (i.e. by reference to standard serving sizes).

As this HHRA considers cumulative exposure from multiple pathways, the potential risk from up to four CoPC and specific pathways are summed together. Therefore, it is important to select ingestion rates that are not overly conservative as the summing of risk from the estimate intakes, for each CoPC, for many pathways, would have a compounding effect.

The ingestion rates selected as being representative of typical and upper ingestion rates for child and adult receptors are identified in Appendix F.

The potential impact on the risk estimates of different ingestion rates to those adopted by the HHRA were considered as part of the sensitivity analysis presented in Section 8.3 and Appendix K.

5.1.5 Intakes via Infant Ingestion of Breast Milk

PFAS have the potential to bioaccumulate. A number of studies have shown that PFOS and PFOA can be transferred to breast milk (von Ehrenstein et al. 2009, Völkel et al. 2008, Jain 2013, White et al. 2009).

The enHealth (2016a) Guidance Statements on Perfluorinated Chemicals state:

‘the significant health benefits of breast feeding are well established and far outweigh any potential health risks to an infant from any PFOS or PFOA transferred through breast milk’.

Similar statements have also been made by other international authorities, including the Agency for Toxic Substances and Disease Registry (ATSDR, 2016), State of New Jersey Department of Health (2015) and Massachusetts Department of Environmental Protection (2015).



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Most recently (July 2017) the Commonwealth Department of Health provided the following advice in consideration of this pathway:

‘The TDI is the estimate of the amount of a chemical in food or drinking water, expressed on a body weight basis, that can be ingested daily over a life-time without appreciable health risk to the consumer.

The TDI is expressed in proportion to body weight to extrapolate between test animals and humans, and also to take into account differences in human size (e.g. infants and children compared with adults).

Increased susceptibility associated with different life stages, including the embryo, foetus, and neonate is taken into account as part of risk assessment by experimental studies in animals throughout different life-stages.

Therefore, provided the TDI is not exceeded for the mother no additional human health risk assessment is required for the breast feeding infant.’

For this assessment it is therefore considered that the TDI is protective of all life stages, including a breastfed infant. Therefore, no separate risk characterisation of infant exposure via breastmilk was undertaken in this HHRA. The assessment of potential risks to an infant via breastmilk was undertaken by comparing the mother’s intake with the TDI. If the risk is acceptable for the mother, then it follows that the risk would be acceptable for the breastfed infant. Therefore, the HHRA outcome for the mother is also representative of potential risks to a breastfed infant.

5.2 Chicken Egg PFAS Residue Study

5.2.1 PFAS Transfer Factors for Laying Hens

AECOM engaged Scolexia Pty Ltd (Scolexia), a specialist avian health consultancy, to develop a methodology for, and undertake, a research study to evaluate PFAS transfer from poultry drinking water to chicken eggs. In addition, this study aimed to evaluate the rate at which PFAS residues in chicken eggs decline over time following the cessation of exposure via drinking water. The objectives of the study were to:

characterise PFAS residues (at or near steady state) in chicken eggs from birds exposed to a range of PFOS, PFHxS, PFOA and PFHxA concentrations relevant to the IA via drinking water

evaluate the rate at which PFAS residues in chicken eggs decline over time following the cessation of exposure via drinking water.

The study methodology and outcomes are described in the report in Appendix L2 titled Evaluation of Residues in Hen Eggs after Exposure of Laying Hens to Water Containing Per and Poly-Fluoroalkyl Substances (Scolexia, 2017). The key conclusions of the study are summarised below.

The lack of any clinical impact of PFAS treatment on the health or productivity of the birds and on weight gain in the birds can be interpreted as an indication of the lack of observable adverse health effects of PFAS compounds when adult hens are exposed at the range of PFAS concentrations evaluated in the study. It is noted however that the interpretation of the potential for health or productivity effects in chickens is limited by the fact that diagnostic health parameters were not collected and the study was of a limited exposure duration.

A linear relationship was observed between the rates of PFAS intake and elimination in eggs at or near steady state for all four PFAS studied (PFOS, PFHxS, PFOA, PFHxA).

Transfer factors were estimated for each of the four PFAS, representing the ratio of PFAS elimination rate in the edible portion of eggs (mg/day) to the PFAS dietary intake rate by the hen (mg/day), as follows:

- PFOS elimination via the edible portion of eggs was equivalent to PFOS intake via drinking water (i.e. a transfer factor of 1). It is noted that there was some uncertainty associated with the estimation of PFOS intake due to variability in measured concentrations in water and suspected sorption to the plastic of water supply lines; however, it is considered this would overestimate rather than underestimate the transfer factor.



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- The average PFHxS transfer factor was 0.689.

- The average PFOA transfer factor was 0.456.

- Elimination of PFHxA in eggs was substantially lower, and it was only detected in eggs above the laboratory LOR at the highest treatment concentration. The average PFHxA transfer factor for this treatment group was 0.005.

The four PFAS studied by Scolexia (2017) were primarily eliminated in the yolk of the egg, rather than the white.

Further details on the Chicken Egg PFAS Residue Study are presented in Appendix L. The transfer factors determined by Scolexia (2017) were used by AECOM to compare theoretical modelled PFOS and PFHxS concentrations in the edible portion of eggs with actual PFOS and PFHxS concentrations measured in the edible portion of eggs collected from the IA. Overall, there was considered to be an acceptable correlation between measured and modelled concentrations, with the theoretical transfer factors tending to overestimate rather than underestimate PFAS concentrations in the edible portion of eggs. It was concluded that the Scolexia (2017) transfer factors were conservatively appropriate for use to evaluate potential human exposure via consumption of backyard eggs in a HHRA.

The Scolexia (2017) transfer factors have therefore been adopted for use in this HHRA to estimate theoretical PFAS concentrations in the edible portion of eggs corresponding with the soil and groundwater EPC. This conservative approach results in estimated concentrations of PFAS in eggs of backyard poultry that are greater than the concentrations measured in the backyard egg samples collected during the off-Site biota investigations from 2016 and 2017.

5.2.2 Reduction in PFAS in Eggs After Exposure Ceases

Under circumstances where exposure of backyard chickens to media containing detectable PFAS can be prevented (e.g. supply chickens with town water from the mains supply and/or move free range chickens to areas where soils are not impacted by PFAS) the information from the depuration phase of this Study can be used to estimate the time required for concentrations of PFAS to decrease to less than the laboratory LOR (0.0003 mg/kg for PFOS and PFOA, 0.0005 mg/kg for PFHxS and PFHxA).

Based on the maximum daily average PFAS concentrations reported in eggs from treatment group T5 (hens exposed to an average of 505.7 ug/L PFOS+PFHxS in their drinking water), and the longest average elimination half-life (seven days for PFHxS), Scolexia (2017) estimated that a withholding period of 100 days after cessation of PFAS exposure to hens would likely be required for all four PFAS studied to reduce to concentrations less than the laboratory LOR in eggs from backyard poultry in the IA. This estimate incorporates a number of safety factors:

It incorporates an additional 30% protection factor to account for uncertainties in the study.

It is based on initial PFAS concentrations in eggs equal to the maximum daily average, which was greater than the longer-term average over the inferred plateau period used to estimate the TF.

It is based on initial PFAS concentrations in eggs from the Study that corresponded with treatment concentrations in hens drinking water that were more than six times higher than the maximum PFOS+PFHxS concentrations reported in groundwater off-Site in the Oakey IA, and approximately three times higher than the maximum PFOS+PFHxS concentrations reported in groundwater off-Site in the Williamtown IA.

The LORs for PFOS and PFHxS are more than one order of magnitude lower than the trigger point published by FSANZ (2017) for PFOS+PFHxS of 0.011 mg/kg. The trigger point is the concentration that a child could intake in eggs at the upper 90th percentile consumption rate for a lifetime without exceeding the tolerable daily intake (assuming eggs was their only source of PFAS).

It is important to note that all sources of potential PFAS intakes by chickens (e.g. water and soil) should be mitigated for the PFAS concentrations in eggs to decrease at the rate indicated in this estimate.



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5.3 Plant PFAS Uptake Study

In 2017 AECOM designed and facilitated a Plant PFAS Uptake Study, located at RAAF Base Williamtown, to determine theoretical uptake factors which could be utilised within this report. The objective of the Plant PFAS Uptake Study was to collect a statistically reliable and robust data set of PFAS uptake into fruit and vegetables that can be utilised to:

refine the uptake factors and exposure concentrations adopted in the HHRA

support management decisions for advising on best practices to the local community regarding irrigation with groundwater and consumption of edible home grown plants and vegetables.

The study used vegetable and fruit crop plants grown in a controlled greenhouse environment. Test plants included radish, beetroot, arugula, cucumber, strawberry, tomato and alfalfa.

Refer to Appendix M for further detail on the Plant PFAS Uptake Study and the transfer factors adopted in this HHRA.

5.4 Equations for Estimation of Exposure

The exposure assessment equations relevant to the identified receptors and identified potentially complete pathways are presented within Appendix G. Exposure is estimated for each chemical and pathway separately.

Exposure via ingestion and dermal contact pathways is represented as a daily chemical intake in units of mg/kg body weight (bw)/day.

US EPA (2009) Risk Assessment Guidance for Superfund (RAGS) Part F recommends that when estimating risk via inhalation pathways (i.e. vapour and dust), risk assessors should use the concentration of the chemical in air as the exposure metric (e.g. mg/m3), rather than estimating a daily inhalation intake of a chemical in air based on inhalation rate and body weight. This approach is recommended by US EPA (2009) ‘because the amount of the chemical that reaches the target site is not a simple function of ingestion rate and body weight. Instead, the interaction of the inhaled contaminant with the respiratory tract is affected by factors such as species-specific relationships of exposure concentrations (ECs) to deposited/delivered doses and physiochemical characteristics of the inhaled contaminant’.

However, for PFAS there are no inhalation-specific TRV available that would allow a separate evaluation of intakes via this pathway. As such, in this HHRA the estimated inhalation exposures to indoor and outdoor airborne dust are compared to a tolerable concentration in air that has been estimated in accordance with the approach typically adopted by US EPA where inhalation-specific TRV are not available, which involves multiplying the TDI by inhalation rate (20 m3/day) and dividing by average adult body weight (70 kg).

5.5 Exposure Point Concentrations

A key element of the exposure assessment process is estimation of the concentration of CoPC in environmental media. This concentration – termed the exposure point concentration (EPC) – is an estimate of the concentration of the chemical in the medium that the population is exposed to, at the location where exposure is predicted to occur. EPC are identified for each ‘exposure unit’, which is defined as the area throughout which a receptor moves and encounters an environmental medium for the duration of exposure. Typically, an individual receptor is assumed to be equally exposed to media within all portions of the exposure unit over the time frame of the risk assessment.

5.5.1 EPC Based on Measured Concentrations of PFAS

Sufficient data were available for measured concentrations of PFAS in the following media from the IA to inform the selection of EPC for this HHRA:

soil

groundwater

sediment



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surface water

cattle milk (Groundwater Zone 1 only – refer to discussion below for other Groundwater Zones)

backyard chicken eggs

fish (discussed further below)

yabbies (discussed further below)

5.5.1.1 Fish

Samples of fish were collected within the IA from Oakey Creek and Westbrook Creek. The fish species targeted were those that the Queensland Department of Agriculture and Fisheries indicated are commonly caught and consumed by recreational anglers in Oakey Creek, however where these were not present other species were collected. Both herbivorous and carnivorous fish were sampled.

For the selection of EPC for consideration in this HHRA, the data set was limited to the following fish considered to be edible by humans: European Carp, Bony Bream, Golden Perch and Spangled Perch. Additionally, only fish that were large enough to have fillets of flesh removed for sample analysis were included (i.e. sizes ranging from 11.3 cm to 46.8 cm). Small fish that were analysed whole were excluded because these are considered unlikely to be representative of specimens typically consumed by humans, and as such, this has resulted in fish samples collected from Westbrook Creek being excluded from the selection of EPC.

Figure 4 presents the distributions of PFOS, PFHxS, PFOA and PFHxA concentrations in these herbivorous and carnivorous fish tissue samples collected in 2016 and 2017. The distributions indicate that although carnivorous fish are likely to accumulate higher PFOS and PFHxA concentrations, the herbivorous fish contain concentrations of PFOA that were not detected in the carnivorous fish tissue samples. As such, as a conservative measure, no distinction was made between carnivorous and herbivorous fish in the selection of EPC in this HHRA. The distinction between herbivorous and carnivorous fish is included in the sensitivity assessment (refer to Section 8.3).

The EPC for fish tissue used in the HHRA were therefore the median detected PFAS concentrations in samples of European Carp, Bony Bream, Golden Perch and Spangled Perch collected from Oakey Creek and of a size large enough to remove a fillet for sample analysis. The EPC adopted for fish tissue are presented in Table 46.

Figure 4 Box plot of PFAS distribution in fish tissue collected in 2016 and 2017



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5.5.1.2 Yabbies

The sample locations for yabbies were spread throughout the publically accessible creeks to provide representative biota data coverage across the IA. A total of 45 yabbies were collected from Oakey and Doctor Creek. Table 41 presents a summary of the yabby data for each creek used to inform this HHRA.

Approximately 44% of the yabby samples were collected from Doctor Creek, however detections of PFAS were limited to one sample (0.0036 mg/kg PFOS). As such, as a conservative measure, the EPC for the yabby tissue used in the HHRA were the median detected PFAS concentrations in yabbies collected from Oakey Creek.

Table 41 Summary of yabby samples used to inform the HHRA

CoPC Number of locations

Number of samples

Min (mg/kg)

Max (mg/kg)

Median (mg/kg)

Number of detects

Oakey Creek

PFOS 11 25 0.00083 0.37 0.032 25

PFHxS 11 25 <0.0005 0.031 0.0048 22

PFOA 11 25 <0.0003 0.0036 0.00075 17

PFHxA 11 25 <0.0005 - - 0

Doctor Creek

PFOS 9 20 <0.0005 0.0036 0.0036 1

PFHxS 9 20 <0.0005 <0.0005 - 0

PFOA 9 20 <0.0003 <0.0003 - 0

PFHxA 9 20 <0.0005 <0.0005 - 0

Select yabby samples were dissected such that the tail flesh was analysed separately to the remainder of the yabby. A comparison of the reported PFAS concentrations in each part indicated lower average concentrations of the four CoPC were reported in the tail flesh compared to the rest of the yabby. For the purpose of selecting an EPC, all samples were considered as a conservative approach, and because there is the potential for yabbies to be cooked whole.



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Figure 5 Box plot of PFAS distribution in yabby tissue collected in 2016 and 2017

5.5.2 EPC Based on Modelled Concentrations of PFAS

In the absence of direct measurement data, environmental sampling and predictive models are commonly used to estimate EPC.

5.5.2.1 Cattle Meat

Consistent with the 2016 HHRA, potential PFAS concentrations in the muscle tissue of cattle raised in the IA have been estimated using modelling from blood serum data. It is to be noted that no new blood serum data have been collected by AECOM since 2016 or are used in the HHRA.

For cattle in Groundwater Zone 2, there was sufficient blood serum data to estimate PFAS concentrations in red meat from the measured PFAS concentrations in blood serum. For Groundwater Zone 1 and Zone RoIA, there were no cattle blood serum samples able to be collected by AECOM to inform the HHRA. Therefore, the PFAS concentrations in cattle blood serum were theoretically estimated based on cattle intakes of PFAS based on the soil and groundwater EPC for those Groundwater Zones, and adopting the simple first order one compartment steady state pharmacokinetic model described in Appendix G20. The parameters summarised in Table 42 were identified as representative of cattle dietary intakes of various media.

Table 42 Adopted beef cattle exposure parameters

Exposure parameter Unit Value Source

Cattle soil ingestion rate kg/day 2.42 American Petroleum Institute (API, 2004)

Cattle plant ingestion rate kg/day 13.5 API (2004)

Cattle water ingestion rate L/day 100 Department of Primary Industries (DPI, 2014)

Based on the cattle dietary intake estimates presented in Table 42 and the relative magnitudes of PFAS concentrations reported in groundwater, soil and pasture plant samples from the IA, it is considered that ingestion of groundwater is likely to be the primary contributor to PFAS intakes by beef cattle. As discussed in Section 5.5.3, pasture plants were only sampled at a limited number of properties in the IA and these data were not used to estimate cattle blood serum PFAS



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concentrations. It is noted that the estimated cattle blood serum PFOS and PFHxS concentrations were greater than the concentrations reported in samples collected by AECOM and Bräunig et al. (2017), as summarised in Section 4.5.3, and are therefore likely to be conservative even though PFAS data from pasture plant samples were not considered in the estimates.

Livestock meat production is the main type of commercial food production operation identified in all three Groundwater Zones that may be relevant to dietary intakes of commercial agriculture workers and their families. Cattle meat concentrations were estimated separately for home grown or backyard livestock that may be consumed by residents, compared with for commercially raised livestock that may be consumed by commercial agriculture workers and their families, using the relevant soil and groundwater EPC identified for each of these scenarios.

The assessment of ingestion of home grown red meat has been based on PFAS concentrations estimated in muscle tissue. It is noted that concentrations of PFOS and PFHxS between three and 16 times higher are likely to be encountered in offal, such as liver and kidneys, compared to muscle tissue, based on the following values identified by ToxConsult (2016a, 2016b):

For PFOS, the liver: serum ratio is 0.3 for male cattle and 1.6 for female cattle, and the kidney: serum ratio is 0.07 for male cattle and 0.6 for female cattle, whereas the muscle tissue: serum ratio is 0.1 for both male and female cattle.

For PFHxS, the liver: serum ratio is 0.2 for cattle, and the kidney: serum ratio is 0.3, whereas the muscle tissue: serum ratio is 0.05 for both male and female cattle.

ABS (2014) indicates that children aged 2 –6 years are unlikely to consume any offal. The mean ingestion rate of cattle meat for an Australian adult is 57 g/day, whereas the mean ingestion rate of mammalian offal for an Australian adult is 0.3 g/day (ABS, 2014). Therefore, average rates of offal consumption are more than 100 times lower than rates of cattle meat consumption. Considering these data, at average consumption rates it would be expected that overall PFAS exposure via offal consumption would be lower than via meat consumption.

Therefore, consumption of offal has not been included as a separate pathway in this HHRA. As a precautionary approach, where individuals consume offal sourced from a property in the IA, any precautionary recommendations associated with red meat consumption should also be applied to offal consumption.

5.5.2.2 Cattle Milk

Cattle milk samples were only available from Groundwater Zone 1. Potential PFAS concentrations in the milk of home grown or backyard cattle raised in Groundwater Zone 2 and Zone RoIA have therefore been estimated from measured or modelled blood serum data (as discussed above), based on the relevant soil and groundwater EPC identified for the residential scenario in these two Groundwater Zones.

Commercial milk production is only known to occur in Groundwater Zone RoIA. Cattle milk concentrations were estimated from modelled blood serum concentrations, based on the relevant soil and groundwater EPC identified for the commercial agriculture scenario in Groundwater Zone RoIA.

5.5.2.3 Home Grown Plants for Human Consumption

The numbers of home grown fruit and vegetable primary samples that have been collected in each Zone of the IA are summarised in Table 43. Although only five fruit samples and four root/tuber samples were collected from Groundwater Zone RoIA, this is considered an acceptable data set to demonstrate that PFAS exposure via these types of home grown produce is not complete in the IA, because PFAS were not detected in any of the fruit or root/tuber samples that were collected from Groundwater Zone 1 or Zone 2, where plants were exposed to greater PFAS concentrations in soil or water.

PFAS were only detected in leafy green vegetable samples collected from Groundwater Zone 2. However, only one leafy green vegetable sample was collected from Groundwater Zone 1, and six leafy green vegetable samples were collected from Groundwater Zone RoIA. Therefore, when selecting EPC for inclusion in the 2017 HHRA, the measured concentrations of PFAS in plant tissue have been supplemented by theoretical estimates of concentrations of PFAS in leafy green vegetables based on the transfer factors (TF) and modelling approach described in Appendix M.



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Table 43 Number of home grown fruit and vegetable primary samples collected in each Zone of the IA (number of primary samples with detectable PFAS in brackets)

Groundwater Zone Fruit Leafy green vegetables Root/tuber vegetables

Zone 1 25 (0) 1 (0) 7 (0)

Zone 2 39 (0) 29 (14) 8 (0)

Zone RoIA 5 (0) 6 (0) 4 (0)

Total for entire IA 69 (0) 36 (14) 19 (0)

Commercial production of leafy green vegetables that could also be consumed at home by commercial agriculture workers and their families is not known to occur within the IA; therefore, this was not considered to be a complete pathway requiring assessment in the HHRA. FSANZ (2017a) concluded that ‘the available data from the 24th Australian Total Diet Study, recent results on imported fish and prawn samples purchased from Sydney retail outlets and a comprehensive review of the literature, suggests that dietary exposure to PFOS, PFOA and PFHxS from the general food supply is likely to be low as the majority of samples in studies reported in Australia and elsewhere did not detect these chemicals in testing’. Therefore, the potential risks to the general public associated with food from the IA sold into the food supply are considered to be low and were not assessed in this HHRA.

5.5.3 Media Sampled but Not Used to Evaluate Human Exposures

Other biota were sampled (e.g. rabbits and earthworms) but not carried forward in the HHRA because exposure pathways associated with these media are considered to be incomplete, and the main purpose of sampling was to inform the 2017 ERA.

Pasture plants were sampled during 2016 from three properties located in Groundwater Zone 1 and one property located in Groundwater Zone 2. Although pasture plants may be consumed by livestock that are subsequently consumed by humans, water ingestion is considered to represent the most significant pathway for livestock exposure to PFAS. Therefore, PFAS concentrations detected in pasture plants have not been assessed in the HHRA.

Sheep blood serum was sampled in 2016, but the maximum PFAS detections were lower than measured in samples of cattle blood serum. Because the serum: muscle tissue PFOS ratios reported for sheep and cattle (ToxConsult, 2016a) are similar, it is expected that the magnitude of estimated PFOS concentrations in cattle muscle tissue is greater than in lamb tissue. No information was found in the literature to inform the estimation of PFHxS concentrations in lamb tissue (ToxConsult, 2016b). Therefore, the EPC for red meat consumption were based on blood serum data for cattle, which is considered to be conservative for consumers of sheep meat.

Sheep milk was sampled in 2016, but there was no information to suggest that people within the DA consume sheep milk. These data were therefore not considered further when estimating human intakes of milk in the 2016 HHRA.

Loose non-residential surface soil samples collected manually to understand the distribution of PFAS that may have migrated by wind resuspension or by flood inundation were excluded as they are less likely to be directly contacted on a routine basis by the general population (PFAS concentrations were generally higher in these non-residential soil samples, and these samples have been included in the sensitivity assessment, refer to Section 8.3). Surface water and sediment characterised in on- and off-Site drainage channels are unlikely to be directly contacted by people undertaking recreational activities (i.e. it is considered unlikely that the drainage channels originating from the Site would be used for recreational fishing, boating or swimming). It is assumed that potential exposure pathways for intrusive maintenance workers on the Site can be managed by Defence specifying minimum requirements for inclusion in health and safety plans for intrusive works to be undertaken on the Site.



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5.5.4 Statistical Approach Adopted When Selecting EPC

The EPC adopted in the HHRA for groundwater, surface water, soil, sediment were maximum concentrations reported in each Zone, because it is intended that the HHRA provide outcomes that can be applied to all people within the IA (including those exposed to PFAS concentrations greater than the average in each Zone). Using the maximum concentration reported in each Zone is likely to overestimate intakes for the average person exposed to PFAS impacts in the IA. However, if there is low or negligible risk from certain groundwater use at the maximum concentration, lower concentrations will have even lower risks.

Where sufficient data were available, the EPC adopted in the HHRA for plants and animals consumed by humans were the median of detected PFAS concentrations, as these were considered most representative of long term dietary intakes for frequent consumers of those foods as per FSANZ (2017a) guidance. The EPC adopted for livestock milk and blood were the maximum of detected PFAS concentrations due to the limited samples available at the time of this assessment.

It is noted that the EPC for off-Site groundwater are only based on data that stakeholders have agreed can be published and used for the HHRA. PFAS may have been detected in other samples, but the stakeholders have not agreed to the data being published or used in the HHRA.

5.5.5 Summary of Adopted EPC

The EPC adopted in the HHRA and the basis for their selection are summarised in Table 44, Table 45 and Table 46 for off-Site receptors in the IA, and Table 47 for on-Site personnel.



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Table 44 EPC for off-Site residents in the IA

Media Adopted EPC Rationale


Soil

Soil (mg/kg) –

Groundwater Zone 2

0.18 0.067 0.0073 0.01 Maximum concentrations reported in off-Site surface soils down to 1 m bgl, irrigated with groundwater containing detectable concentrations of PFAS in Groundwater Zone 2. Historical data set used from 2015 to 2017.

The 0–1 m bgl depth range is considered most representative of soils that may be incidentally contacted by off-Site residents during routine activities, including non-intrusive activities and shallow digging in gardens.

Conservatively adopted because no clear correlation was observed between PFAS concentrations in groundwater and PFAS concentrations in irrigated soil.

Concentrations are considered unlikely to be detectable at locations where groundwater or surface water containing detectable concentrations of PFAS has never been used for irrigation, except where surface water flooding may have occurred in the past.

Soil (mg/kg) –

Groundwater Zone 1

0.07 0.01 0.0014 0.0008 Maximum concentrations reported in off-Site surface soils down to 1 m bgl, irrigated with groundwater containing detectable concentrations of PFAS in Groundwater Zone 1. Historical data set used from 2015 to 2017.

Soil (mg/kg) –


0.012 0.0016 0.0007 0.001 Maximum concentrations reported in off-Site surface soils down to 1 m bgl, irrigated with groundwater containing detectable concentrations of PFAS in Groundwater Zone RoIA. Historical data set used from 2015 to 2017.



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Groundwater

Groundwater Zone 2 (mg/L)

0.0398 0.033 0.00203 0.00686 Maximum PFOS, PFHxS, PFOA and PFHxA concentrations reported in off-Site Groundwater Zone 2, in wells screened in the Oakey Alluvium. Where insufficient data were available to determine screen depth, it was conservatively assumed the well was screened in the Upper Oakey Creek Alluvium aquifer. The maximum concentrations were reported at location GW20 (residential bore). Historical data set used from 2013 to 2017.

Maximum concentrations were adopted rather than another statistic (e.g. average or 95th percentile) because it is intended that the HHRA provide an assessment relevant to all people using groundwater within Groundwater Zone 2. Using the maximum concentration is likely to overestimate intakes for the average groundwater user in this Groundwater Zone.


0.00491 0.00502 0.00081 0.00076 Maximum concentrations reported in off-Site Groundwater Zone 1, in wells screened within Oakey Alluvium. Where insufficient data were available to determine screen depth, it was conservatively assumed the well was screened in the Upper Oakey Creek Alluvium aquifer. The maximum concentrations were reported at locations GW10 and GW36 (residential bores). Historical data set used from 2013 to 2017.

Groundwater Zone RoIA (mg/L)

0.00008 0.00027 0.00005 0.00005 Maximum concentrations reported in off-Site Groundwater Zone RoIA, in wells screened within Oakey Alluvium. Where insufficient data were available to determine screen depth, it was conservatively assumed the well was screened in the Upper Oakey Creek Alluvium aquifer. The maximum concentrations were reported at residential bore locations. Historical data set used from 2013 to 2017.



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Cow Milk

Cow Milk


0.043 0.0036 0.000024 (i.e. <LOR)

-- No cow milk samples have been collected in Groundwater Zone 2. Hence, the PFAS concentrations in cow milk were estimated based on theoretical PFAS concentrations in cattle blood serum from this Groundwater Zone (which were in turn estimated based on the soil and groundwater EPC for Groundwater Zone 2), and adopting empirical blood serum to milk transfer factors from published, peer-reviewed literature. EPC for PHFxA was not estimated as no blood serum half-life value for cattle was available from literature.

Cow Milk

Groundwater Zone 2 Maximum blood serum concentration adopted in the HHRA (mg/L)

2.3 0.36 0.0029 --

Cow Milk


0.0011 Not Detected Not Detected Not Detected Maximum concentrations measured in cow milk samples collected in Groundwater Zone 1. PFOS was detected in one out of five cow milk samples collected in Groundwater Zone 1.

Cow Milk


0.00036 0.000032 (i.e. <LOR)

0.00000072 (i.e. <LOR)

-- No cow milk samples have been collected in Groundwater Zone RoIA. PFAS concentrations in cow milk were estimated based on theoretical PFAS concentrations in cattle blood serum from this Groundwater Zone (which were in turn estimated based on the soil and groundwater EPC for Groundwater Zone RoIA), and adopting empirical blood serum to milk transfer factors from published, peer-reviewed literature. EPC for PHFxA was not estimated as no blood serum half-life value for cattle was available from literature.

Cow Milk

Groundwater Zone RoIA Maximum blood serum concentration adopted in the HHRA (mg/L)

0.019 0.0032 0.000089 --



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Chicken Eggs

Chicken Eggs

Groundwater Zone 2 (mg/kg)

0.20 0.10 0.0045 0.00015 The potential range of concentrations in backyard chicken eggs was estimated by calculating the chronic daily intake (CDI) of PFAS by chickens (estimated based on the soil and groundwater EPC for each Groundwater Zone) and applying the Scolexia (2017) transfer factor for PFAS elimination in eggs. The laying rate and average weight of the edible portion of the eggs were parameters used to calculate the concentration in eggs.

As noted in Section 5.2, a chicken egg PFAS uptake study was undertaken by Scolexia (2017) to evaluate PFAS residues (at or near steady state) in chicken eggs from birds exposed to a range of PFAS concentrations via drinking water. In addition, the study aimed to evaluate the rate at which PFAS residues in chicken eggs decline over time following the cessation of exposure via drinking water. The outcome of the study was determination of suitable transfer factors characterising PFAS elimination in eggs for use in the HHRA. This egg study is further discussed in Appendix L.

Chicken Eggs

Groundwater Zone 1 (mg/kg)

0.035 0.016 0.0017 0.000016

Chicken Eggs

Groundwater Zone RoIA (mg/kg)

0.0028 0.00099 0.00016 0.000002

Green Vegetables

Green Vegetables Groundwater Zone 2 (mg/kg)

0.043 0.035 0.0027 0.027 Theoretical estimates of concentrations of PFAS in leafy green vegetables based on the TF and modelling approach described in Appendix M.

Green Vegetables Groundwater Zone 1 (mg/kg)

0.0053 0.0053 0.0011 0.0030

Green Vegetables Groundwater Zone RoIA (mg/kg)

0.000087 0.00029 0.000067 0.00020



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Ingestion of Red Meat


Groundwater Zone 2 Maximum blood serum concentration (mg/L)

6.4 0.44 0.0022 -- No locations for cattle blood serum sampling were identified in Groundwater Zone 2. As such, the PFAS concentrations in cattle blood serum were theoretically estimated based on the soil and groundwater EPC for Groundwater Zone 2, and adopting the simple first order one compartment steady state pharmacokinetic model described in Appendix G20. PFAS concentrations in beef muscle tissue were then estimated by adopting empirical blood serum to muscle tissue transfer factors from published, peer-reviewed literature. EPC for PHFxA was not estimated as no blood serum half-life value for cattle was available from literature. Ingestion of Red

Meat

Groundwater Zone 2 Estimated muscle tissue concentration adopted in the HHRA (mg/kg)

0.62 0.021 0.00022 (i.e. <LOR)

--



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0.35 0.13 0.0014 Not Detected The 2016 HHRA identified that the magnitude of estimated PFOS concentrations in cattle muscle tissue is greater than in lamb tissue, and no information was found in the literature to inform the estimation of PFHxS concentrations in lamb tissue. Therefore, the HHRA therefore assesses intakes via red meat consumption based on the maximum estimated PFAS concentrations in beef muscle tissue. PFAS concentrations in beef muscle tissue were estimated based on measured PFAS concentrations in cattle blood serum from this Groundwater one, and adopting empirical blood serum to muscle tissue transfer factors from published, peer-reviewed literature.


Groundwater Zone 1

Estimated muscle tissue concentration adopted in the HHRA (mg/kg)

0.034 0.0063 0.00014 Not Detected



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Groundwater Zone RoIA Maximum blood serum concentration (mg/L)

0.054 0.0039 0.000068 -- No locations for cattle blood serum sampling were identified in Groundwater Zone RoIA. As such, the PFAS concentrations in cattle blood serum were theoretically estimated based on the soil and groundwater EPC for Groundwater Zone RoIA, and adopting the simple first order one compartment steady state pharmacokinetic model described in Appendix G20. PFAS concentrations in beef muscle tissue were then estimated by adopting empirical blood serum to muscle tissue transfer factors from published, peer-reviewed literature. EPC for PHFxA was not estimated as no blood serum half-life value for cattle was available from literature.



Estimated muscle tissue concentration adopted in the HHRA (mg/kg)

0.0052 0.00019 0.0000066 (i.e. <LOR)

--



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Table 45 EPC for off-Site commercial agriculture workers in the IA



Soil

Soil (mg/kg) – Groundwater Zone 2

0.18 0.067 0.0073 0.01 Maximum concentrations reported in off-Site surface soils down to 1 m bgl, irrigated with groundwater containing detectable concentrations of PFAS in properties in Groundwater Zone 2 that are understood by AECOM to be undertaking commercial agricultural operations. Historical data set used from 2015 to 2017.

Soil (mg/kg) – Groundwater Zone 1

0.02 0.002 0.0014 0.0007 Maximum concentrations reported in off-Site surface soils down to 1 m bgl, irrigated with groundwater containing detectable concentrations of PFAS in properties in Groundwater Zone 1 that are understood by AECOM to be undertaking commercial agricultural operations. Historical data set used from 2015 to 2017.

Soil (mg/kg) - Groundwater Zone RoIA

0.0086 0.0016 Not Detected 0.001 Maximum concentrations reported in off-Site surface soils down to 1 m bgl, irrigated with groundwater containing detectable concentrations of PFAS in properties in Groundwater Zone RoIA that are understood by AECOM to be undertaking commercial agricultural operations. Historical data set used from 2015 to 2017.

Groundwater


0.0171 0.00727 0.00075 0.0015 Based on maximum PFAS concentrations in groundwater for properties in Groundwater Zone 2 that are understood by AECOM to be undertaking commercial agricultural operations. Historical data set used from 2013 to 2017.

The maximum concentrations were reported in samples from bore GW27, which is understood to be currently used for stock watering.



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0.00491 0.00337 0.00081 0.00065 Based on maximum PFAS concentrations in groundwater for properties in Groundwater Zone 1 that are understood by AECOM to be undertaking commercial agricultural operations. Historical data set used from 2013 to 2017.

The maximum concentrations were reported in samples from bore GW10, which is understood to be currently used for stock watering.


Not Detected Not Detected Not Detected Not Detected PFAS not detected in groundwater in Groundwater Zone RoIA from properties that are understood by AECOM to be undertaking commercial agricultural operations.




3.1 0.11 0.00094 -- No locations for cattle blood serum sampling were identified in Groundwater Zone 2. As such, the PFAS concentrations in cattle blood serum were theoretically estimated based on the soil and groundwater EPC for Groundwater Zone 2, and adopting the simple first order one compartment steady state pharmacokinetic model described in Appendix G20. PFAS concentrations in beef muscle tissue were then estimated by adopting empirical blood serum to muscle tissue transfer factors from published, peer-reviewed literature. EPC for PHFxA was not estimated as no blood serum half-life value for cattle was available from literature. Ingestion of Red

Meat


0.30 0.0055 0.000092 --



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0.35 0.13 0.0014 Not Detected The 2016 HHRA identified that the magnitude of estimated PFOS concentrations in cattle muscle tissue is greater than in lamb tissue, and no information was found in the literature to inform the estimation of PFHxS concentrations in lamb tissue. Therefore, the HHRA therefore assesses intakes via red meat consumption based on the maximum estimated PFAS concentrations in beef muscle tissue. PFAS concentrations in beef muscle tissue were estimated based on measured PFAS concentrations in cattle blood serum from this Zone, and adopting empirical blood serum to muscle tissue transfer factors from published, peer-reviewed literature. Ingestion of Red

Meat


0.034 0.0063 0.00014 Not Detected



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0.030 0.00049 -- -- No locations for cattle blood serum sampling were identified in Groundwater Zone RoIA. As such, the PFAS concentrations in cattle blood serum were theoretically estimated based on the soil and groundwater EPC for Groundwater Zone RoIA, and adopting the simple first order one compartment steady state pharmacokinetic model described in Appendix G20. PFAS concentrations in beef muscle tissue were then estimated by adopting empirical blood serum to muscle tissue transfer factors from published, peer-reviewed literature. EPC for PHFxA was not estimated as no blood serum half-life value for cattle was available from literature.


Groundwater Zone RoIA Estimated muscle tissue concentration adopted in the HHRA (mg/kg)

0.0029 0.000024 -- --



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Ingestion of Cow Milk

Cow Milk


0.00020 0.0000040 -- -- No cow milk samples have been collected in Groundwater Zone RoIA. PFAS concentrations in cow milk were estimated based on theoretical PFAS concentrations in cattle blood serum from this Groundwater Zone (which were in turn estimated based on the soil and groundwater EPC for Groundwater Zone RoIA), and adopting empirical blood serum to milk transfer factors from published, peer-reviewed literature. EPC for PHFxA was not estimated as no blood serum half-life value for cattle was available from literature.

Cow Milk


0.011 0.00040 -- --

Table 46 EPC for off-Site recreational users of publicly accessible areas in the IA



Soil (mg/kg) 0.18 0.067 0.0073 0.01 Maximum concentrations reported in off-Site surface soils to 1 m bgl, irrigated with groundwater containing detectable concentrations of PFAS. Historical data set used from 2015 to 2017.

The 0 – 1 m bgl depth range is considered most representative of soils that may be incidentally contacted by off-Site receptors during routine recreation activities.

Soil data from residential properties have been adopted for soil exposures in public recreational areas as it is considered that public playing fields could also be irrigated with groundwater/surface water.



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Sediment (mg/kg) 0.034 0.0013 0.0013 0.0004 Maximum concentrations collected from Oakey Creek, Doctor Creek and Westbrook Creek. It is considered unlikely that the ephemeral drainage channels originating from the Site would be used for recreational fishing, boating or swimming.

Surface water (µg/L)

2.3 0.26 0.19 0.11

All Fish (mg/kg) 0.053 0.0013 0.0023 0.001 Median of detected concentrations in all fish tissue (carnivorous and herbivorous) collected from Oakey Creek (refer to Section 5.5.1.1). Fish considered inedible by humans and samples that were not filleted prior to analysis were excluded from the data set.

Yabbies (mg/kg) 0.032 0.0048 0.00075 Not Detected Median of detected concentrations in yabby tissue collected from Oakey Creek (refer to Section 5.5.1.2)

Table 47 EPC for on-Site personnel



Soil (mg/kg) 7.26 0.48 0.045 0.067 Maximum concentrations reported in on-Site surface soils to 0.1 m bgl. Historic data set used from 2010 to 2017.

Soils in the upper 0.1 m are considered most representative of soils that may be incidentally contacted by on-Site personnel during routine non-intrusive activities. Intrusive activities are subject to Defence management procedures on-Site.

The adopted PFOS and PFOA concentrations are conservative for assessing potential risks associated with direct contact because these concentrations were reported in the vicinity of the former fire training area. Soils in this area may be representative of potential for dust generation but are less likely to be contacted directly, due to access restrictions to areas near the runways.

Groundwater (mg/L)

N/A N/A N/A N/A Groundwater is not extracted for use on-Site.



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Sediment (mg/kg) N/A N/A N/A N/A Surface water and sediment in on-Site drainage channels are unlikely to be directly contacted by Site personnel during routine activities. It is assumed that potential exposure pathways for maintenance workers on the Site can be managed via Site standing orders and/or specifying minimum requirements for inclusion in health and safety plans for works to be undertaken on the Site.

Surface water (µg/L)

N/A N/A N/A N/A



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6.0 Toxicity Assessment The toxicity assessment stage of a risk assessment is separated into two components: hazard identification and dose-response assessment. The hazard identification stage is a qualitative description of the capacity of a chemical to cause harm. The dose-response assessment includes the selection of appropriate toxicity criteria from a hierarchy of sources, in accordance with the ASC NEPM 2013.

6.1 Hazard Identification

The hazard identification process involves a review of existing toxicological information from a variety of appropriate sources to describe the capacity of a chemical to produce adverse health effects. A brief summary follows based on the information presented in Appendix I:

PFAS are readily absorbed in the gastrointestinal tract, but are poorly absorbed through the skin.

PFAS are not volatile, but may be inhaled to the lung in association with dust generated from outdoor or household sources.

In human, rat, bovine and monkey plasma, PFAS are very highly bound to albumin and low density lipoproteins, accumulating primarily in the blood, liver and kidney tissue. PFAS do not accumulate in fatty tissue because they have both lipophobic and hydrophobic properties.

PFOS, PFOA, PFHxS and PFHxA are not metabolised in the body. However, some longer chain PFAS may be oxidised in the body to form these compounds.

PFAS are primarily eliminated from the body via urine, in breast milk and via blood loss. The available data indicate that body burdens decrease more rapidly in females than in males.

There is currently no consistent evidence that exposure to PFOS and PFOA causes adverse human health effects (FSANZ, 2017). However, because these chemicals have been shown to have health effects in animals (discussed further below) and because these chemicals persist in humans and the environment, enHealth (2016b) recommended that human exposure to these chemicals is minimised as a precaution.

The toxic effect on humans from acute (i.e. short term) exposure is not known, however no case reports were found in the literature reviewed by ToxConsult (2016a, 2016b) of human health effects from acute exposure to high doses of PFOS. The assessments undertaken by the NSW government have stated that adverse effects from PFAS are thought to occur following long term exposure, therefore, no acute health based assessment is required (WCEP, 2015a, 2015b and 2015c).

The toxic effects on humans from chronic (long term) exposure are not yet well understood. The US EPA (2016) identified potential associations with increased serum cholesterol and decreased body weights at birth, however review of these studies by FSANZ (2017a) concluded that while there is evidence of these associations, it is not possible to determine whether PFOS or PFOA cause the changes, or whether other factors are involved.

Hepatic and developmental toxicity are the most sensitive toxic effects of PFAS in animals. Based on information currently available, extrapolation of animal data to exposure of humans is highly uncertain in part because of large interspecies differences in the toxicokinetics of perfluoroalkyls and some mechanisms of toxicity in animals may not be operant in humans; these issues are strongly interrelated (ATSDR, 2015).

The immunotoxicity of perfluoroalkyls has been investigated in several animal species. Immune effects have been observed in mice following acute- or intermediate-duration perfluoroalkyl exposure, however the available data do not suggest that PFAS are immunotoxic in rats or monkeys. A literature review reported by FSANZ (2017a) concluded that ‘there are both positive and negative studies showing associations for increasing PFOS and PFOA concentrations to compromise antibody production in humans. However, to date there is no convincing evidence for increased incidence of infective disease associated with PFOS or PFOA effects on human immune function’.



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PFOS, PFOA, PFHxS and PFHxA are not mutagenic or genotoxic. PFOS and PFOA have been linked to tumour formation at high exposures in animal tests. For both compounds, tumour formation was observed at exposure doses greater than those at which other health effects were observed. It is also noted that based on the way high exposures to PFOS may induce cancer in rats (the non-genotoxic mechanisms of peroxisome proliferator-activated receptor alpha (PPARα) and constitutive androstane receptor/pregnane X receptor (CAR/PXR) receptor activation) and the differences between rats and humans, the tumour formation observed in rats is unlikely to occur in humans. Epidemiological studies have not provided convincing evidence of a correlation between PFOS and PFHxS and any cancer type in human beings. Although associations between PFOA and some human cancers have been suggested from some epidemiological studies, results have often been contradictory, and a causal relationship cannot be established with reasonable confidence (FSANZ, 2017b).

6.2 Dose-Response Assessment

The objective of the dose-response assessment is to describe effects (adverse and non-adverse) associated with increasing doses of a substance and to identify the toxicity values for each of the PFAS compounds quantitatively assessed for human health risk, namely PFOS, PFOA, PFHxS and PFHxA. The numerical values derived from toxicity dose-response studies are referred to collectively as the TRV.

A threshold dose is considered relevant for chemicals that may be associated with non-carcinogenic effects or carcinogenic effects that are not genotoxic (NHMRC, 1999 and US EPA, 2005). Exposure below the threshold value is not considered to result in any adverse effects over a lifetime of exposure (including non-genotoxic carcinogenicity). Exceedance of the threshold value does not imply that adverse effects will occur, as there are a number of uncertainties and safety factors incorporated into the threshold value adopted; rather, it indicates that exposure needs to be further evaluated.

PFOS, PFOA, PFHxS and PFHxA have been assessed as threshold chemicals, as standard tests for genotoxic carcinogenicity have been negative. Potential health effects that are assessed on the basis of a threshold dose response utilise a threshold value which is termed a TDI. A TDI is a lifetime daily chemical intake below which it is considered unlikely that adverse effects would occur in human populations, including sensitive sub-groups (e.g. the very young or elderly). Hence, the TDI relates to intakes from all sources, including contamination-related impacts as well as background intakes (where relevant).

The determination of a TDI follows the principles outlined in the International Programme on Chemical Safety (IPCS) Environmental health criteria monograph No. 104 (WHO, 1990). Typically, this involves identifying from scientific literature an intake at which experimental studies have shown there to be no observed adverse health effects (termed a NOAEL). The preferred NOAEL for determination of a TDI is the lowest value for the most sensitive species for which reliable studies are available and relevant to toxicokinetics in humans (enHealth, 2012b). Alternatively, a benchmark dose (BMD) or (least preferentially) a lowest observed adverse effect level (LOAEL) may be used. A BMD is the dose associated with a given per cent incidence of effect (e.g. the dose associated with the effect occurring in 5% or 10% of experimental animals). The uncertainty inherent in extrapolation between and within species is then dealt with by dividing the NOAEL, LOAEL or BMD by uncertainty factors (UF). The overall UF can range from 10 to 10,000, depending on the source and quality of data, the biological relevance of the endpoint, and the hazard assessment (enHealth, 2012b).

The adoption of a threshold approach for PFOS, PFOA, PFHxS and PFHxA is consistent with these chemicals being considered to be non-genotoxic. enHealth (2012b) states that non-threshold toxicity should be considered for genotoxic carcinogens, but that the TDI should be used for non-genotoxic carcinogens. WHO (2011) takes a similar approach when setting drinking water guidelines, stating ‘it is generally believed that a demonstrable threshold dose exists for non-genotoxic carcinogens’. Therefore, the TDI was considered to be the appropriate toxicity reference value for assessing PFAS in the HHRA, and is considered to be protective of potential non-genotoxic cancer effects.



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6.2.1 PFOS

FSANZ (2017a) recommended a TDI for PFOS of 0.00002 mg/kg/day, which incorporates:

Point of departure: a Human Equivalent Dose (HED) No Observed Adverse Effect Level (NOAEL) of 0.0006 mg/kg/day, identified based on studies in female rats (Luebker et al, 2005). The critical effects considered were parental toxicity (decreased body weight gain and food consumption) and offspring toxicity (reduced body weight and weight gain).

an Uncertainty Factor (UF) of 30 to account for intraspecies variability in human populations and for interspecies differences in toxicodynamics.

6.2.2 PFOA

FSANZ (2017a) recommended a TDI for PFOA of 0.00016 mg/kg/day, which incorporates:

Point of departure: a HED Lowest Observed Adverse Effect Level (LOAEL) of 0.0049 mg/kg/day based on studies in mice (Lau et al, 2006). The critical effect considered was foetal toxicity.

UF of 30 to account for intraspecies variability in human populations and for interspecies differences in toxicodynamics.

6.2.3 PFHxS

FSANZ (2017a) states ‘there was insufficient toxicological and epidemiological information to justify establishing a TDI for PFHxS. In the absence of a TDI, it is reasonable to conclude that the enHealth (2016) approach of using the TDI for PFOS is likely to be conservative and protective of public health as an interim measure’.

6.2.4 PFHxA

FSANZ (2017a) did not evaluate a TDI for PFHxA. ToxConsult (2016b) derived a provisional TDI for PFHxA of 0.10 mg/kg/day based on a two-year chronic/carcinogenicity study by Klaunig et al (2015). This TRV was based on:

point of departure: NOAEL of 30 mg/kg/day for female rats based on observations of kidney necrosis

UF of 300 to account for animal to human differences in toxicodynamics and toxicokinetics, human variability in toxicodynamics and human variability in toxicokinetics.

It is noted that this is the same TDI value proposed by the Swedish National Food Agency (Livsmedelverket, 2013).

6.2.5 Summary

A summary of the adopted TDI for each of the CoPC is presented in Table 48.



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Table 48 TRV adopted in the HHRA

CoPC Oral TDI

(mg/kg bw/day)

Source Notes

PFOS

and

PFHxS

2 x 10-5 FSANZ (2017a)

Point of departure: a Human Equivalent Dose (HED) No Observed Adverse Effect Level (NOAEL) of 0.0006 mg/kg/day identified based on studies in female rats (Luebker et al 2005)

UF of 30

The FSANZ Report states ‘there was insufficient toxicological and epidemiological information to justify establishing a TDI for PFHxS. In the absence of a TDI, it is reasonable to conclude that the enHealth (2016) approach of using the TDI for PFOS is likely to be conservative and protective of public health as an interim measure’.

The FSANZ (2017) report also states ‘PFHxS and PFOS should be summed for the purposes of dietary exposure assessment and risk characterisation’, therefore this HHRA has considered the risk estimates from PFOS and PFHxS cumulatively, as described in Section 7.2.1.

PFOA 1.6 x 10-4 FSANZ (2017a)

Point of departure: a HED Lowest Observed Adverse Effect Level (LOAEL) of 0.0049 mg/kg/day based on studies in mice (Lau et al, 2006)

UF of 30.

PFHxA 1 x 10-1 ToxConsult (2016b)

Point of departure: a NOAEL of 30 mg/kg/d based on kidney effects in female rats (Klaunig et al., 2015)

UF of 300.

6.3 Background Exposure

Background exposure to chemicals present in the environment can occur as a result of everyday activities or natural sources. These chemicals may be present in food, water and consumer products and represent non-Site based sources of PFAS exposure. ASC NEPM 2013 (Schedule B4) and enHealth (2012b) require that background exposure be taken into account during the assessment of potential human health risk. This has been undertaken by adjusting TDI thresholds to account for non-Site related exposure.

ATSDR (2015) indicates that general population exposure to PFAS is widespread, as PFAS are present in the environment due to their use in surface protection products such as carpet and clothing treatments, and as coating for paper and cardboard packaging. It is noted that dietary background intakes may be sourced from a wide area, which may not be practicable to characterise by sampling, and literature data may therefore provide a more conservative estimate.

Based on a literature review presented in AECOM (2016), ToxConsult (2016a) suggested representative background intakes by Australians for PFOS and PFOA, as summarised in Table 49. These estimates are based on measured serum data from Australians and half-lives used to estimate steady state intakes. No background intake data were identified by ToxConsult (2016b) for PFHxS or PFHxA.



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Table 49 Recommended background intake assumptions for PFOS and PFOA (ToxConsult, 2016a)

Compound Oral TDI

(mg/kg bw/day) Background intake

(mg/kg/day) Background intake as a percentage of oral TDI

PFOS 2 x 10-5 8 x 10-7 (average)

1.4 x 10-6 (upper estimate)

4% (average)

7% (upper)

PFOA 1.6 x 10-4 5.4 x 10-7 (average)

7.8 x 10-7 (upper estimate)

<1% (average)

<1% (upper)

PFHxS 2 x 10-5 No data on intake rates -

PFHxA 1.0 x 10-2 No data on intake rates -



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7.0 Risk Characterisation

7.1 Introduction

Risk characterisation is the final step in the risk assessment process whereby information gathered and derived from the toxicity assessment and the exposure assessment is used to derive quantitative estimates of risk to human health.

PFOS, PFOA, PFHxS and PFHxA have been identified to be associated with a threshold dose-response relationship. The threshold approach assumes that there is a level at which exposure to the chemical does not result in adverse health effects for the general population. The risk assessment undertaken by AECOM has therefore been based on comparison of estimated chronic daily intakes of PFAS to tolerable daily intakes.

7.2 Hazard Quotient and Hazard Index

7.2.1 Overview

The potential for adverse threshold effects resulting from exposure to an individual CoPC has been evaluated by comparing the intake for each exposure pathway, expressed as daily chemical intake per kilogram body weight, with the threshold TRV (adjusted to account for background exposure). The resulting ratio is referred to as the hazard quotient (HQ) and is derived for each pathway in the following manner (ASC NEPM 2013):

HazardQuotient HQIntake

mgkg day

ThreshholdTRVmgkg day

Refer to Appendix G for relevant equations used to estimate intakes for the individual pathways. A potentially unacceptable chemical intake/exposure is indicated if the intake via the identified exposure pathways exceeds the TDI (i.e. if the HQ is greater than 1). To assess the overall potential for adverse health effects posed by exposure to multiple pathways, the hazard quotients for each exposure pathway relevant to a receptor are summed. The resulting sum is referred to as the hazard index (HI):

HQforallrelevantpathways

The threshold HI assumes that there is a level of exposure below which it is unlikely for humans to experience health effects, based on the available toxicological studies. If the exposure level does not exceed the threshold, i.e. HI is equal to or less than 1, then it is reasonable to conclude that no adverse health effects are likely to be realised (ASC NEPM 2013). These low levels of exposure are considered acceptable from a health perspective because they are not likely to be associated with adverse effects, and as such, the risk estimate is referred to herein as ‘low and acceptable’.

Where the HI is greater than 1, the exposure is considered to be above a level which has been determined to have no adverse effects, but this does not necessarily mean that health effects will occur. In this situation, the PFAS exposure estimate is referred to herein as ‘elevated’ and a more detailed and critical evaluation of the risk may be conducted, or further investigation, or appropriate exposure mitigation measures may be considered.



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7.2.2 Cumulative Assessment of PFOS and PFHxS

As described in Section 6.2, the FSANZ (2017) report states that ‘PFHxS and PFOS should be summed for the purposes of dietary exposure assessment and risk characterisation’, therefore this HHRA has considered the risk estimates from PFOS and PFHxS cumulatively. The following equation has been used to determine the HQ for each pathway:

/

/

Mathematically, this is the same as:

/

Therefore the approach adopted in this HHRA of estimating the intakes from PFOS and PFHxS separately, and comparing the estimated HI to the target value of 1 is considered consistent with the approach recommended by FSANZ (2017). Further, it is considered that an alternative approach of summing the EPC for PFOS and PFHxS before estimating intake would not change the outcome of the HHRA.

7.2.3 Estimated HQ and HI

The estimated HI for the receptors identified in Section 4.8.2, based on the adopted typical and upper range exposure parameters discussed in Section 5.1.1, are presented in Appendix J and summarised in Table 50 and Table 51 below.

The HI presented below are the sum of the HQ for PFOS, PFOA, PFHxS and PFHxA, as appropriate, noting that not all four compounds were considered CoPC for each pathway (refer to Section 5.5). Individual HQ for each CoPC and pathway are presented in Appendix J (it is noted that the HQ for PFOS and PFHxS should be considered cumulatively, in accordance with the approach adopted by FSANZ, 2017).

The estimated HQ for PFOS and PFHxS were typically one to two orders of magnitude higher than those for PFOA or PFHxA, and PFOS and PFHxS are therefore considered to be the primary contributors to the estimated HI (refer to Appendix J).

An HI less than a target value of 1 is considered to indicate that cumulative PFAS intakes via identified pathways are unlikely to exceed the relevant TDI and therefore risk to health is low and acceptable.

Consistent with the approach adopted in the 2016 HHRA, the HI in Table 50 do not include potential intakes via ingestion of groundwater used as a source of drinking water supply. This is because this pathway is currently being managed through a precautionary recommendation from Defence not to drink the groundwater within the IA, and provision of water assistance to residents on a case-by-case basis. It is considered that a precautionary approach would be to continue to follow the advice not to use groundwater for drinking water supply within the IA (including water used for cooking). Therefore the total HI presented below are representative of all pathways except drinking of groundwater.

As discussed in Section 4.8.3, the 2016 HHRA and 2017 HHRA Addendum identified a number of precautions that could be followed by people living in the Oakey IA to minimise potential for ongoing PFAS exposure. Consistent with the findings of the 2016 HHRA and 2017 HHRA Addendum, Queensland Health has published health information for the Oakey area on their website (https://www.qld.gov.au/environment/pollution/management/incidents/oakey), which currently states:







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Avoiding or minimise the use of the water for showering/bathing, sprinklers or to fill swimming pools due to the possibility of unintentionally drinking the water’.

Therefore, the following discussion also includes a summary of HI for the upper range exposure scenarios for all pathways excluding those subject to the above precautionary recommendations (presented in Table 52 below).

7.3 Summary of HI for Pathways Currently Complete in IA

7.3.1 Cumulative HI for Potentially Complete Pathways Excluding Drinking Groundwater

Table 50 presents the calculated HI for all combined cumulative pathways, excluding the drinking of groundwater pathway.

Table 50 Summary of estimated Hazard Indices (2 significant figures)

Receptor

HI – Typical exposure parameters

HI – Upper range exposure parameters

Adult Child Adult Child


Residential 0.044 0.12 0.36 1.1

Commercial agriculture worker * 0.017 0.053 0.14 0.36

Groundwater Zone 1

Residential 0.57 1.5 5.0 15

Commercial agriculture worker * 0.20 0.45 1.8 4.1

Groundwater Zone 2

Residential 4.6 13 43 124

Commercial agriculture worker * 1.5 3.5 14 32

Entire IA (All Groundwater Zones)

Recreational users of local waterways 0.0097 0.031 1.1 2.4

On-Site personnel 0.090 - 0.12 -

Notes:

Bold HI exceed the target value of 1 (discussed above)

* = It is considered likely that an adult commercial agriculture worker and their families (including children who do not work at the

property) could consume livestock from the property at which they are employed and would be likely to do so at a higher rate

than residents in the general community.

As discussed in Section 4.8.2, residents within the IA may also be exposed via the activity-specific pathways identified for other receptor groups (e.g. a resident in the IA may also work at the Site or elsewhere in the IA, and/or undertake recreational activities in local waterways). Pathways specific to recreational, commercial and on-Site receptors have, however, been described separately in the preceding sections of this report because these receptors may reside outside the IA. Potential HI for residents within the IA who also undertake recreational or commercial activities within the IA have been evaluated by addition of the HI, as presented in Table 51.



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Table 51 Summary of Estimated Hazard Indices – Combined Exposure Scenarios

Receptor

HI – Typical exposure parameters

HI – Upper range exposure parameters

Adult Child Adult Child


Resident who is also employed as a commercial agriculture worker in the IA or is the child of a commercial agriculture worker *

0.050 0.15 0.36 1.1

Resident who also uses local waterways for recreation

0.054 0.15 1.5 3.5

Resident who is also employed at the Site 0.13 - 0.48 -

Groundwater Zone 1

Resident who is also employed as a commercial agriculture worker in the IA or is the child of a commercial agriculture worker*

0.69 1.8 5.8 16


0.58 1.5 6.1 17

Resident who is also employed at the Site 0.66 - 5.1 -

Groundwater Zone 2

Resident who is also employed as a commercial agriculture worker in the IA or is the child of a commercial agriculture worker*

4.8 14 40 117


4.6 13 44 126

Resident who is also employed at the Site 4.7 - 43 -

Notes:

Bold HI exceed the target value of 1

* = It is considered likely that an adult commercial agriculture worker and their families (including children who do not work at the

property) could consume livestock from the property at which they are employed and would be likely to do so at a higher rate

than residents in the general community.

7.3.2 Cumulative HI for Pathways Not Currently Subject to Precautionary Recommendations

As discussed in Section 7.2.3, Queensland Health has identified a number of precautionary measures, consistent with the findings of the 2016 HHRA and 2017 HHRA Addendum, which could be followed by Oakey residents to minimise their potential for ongoing PFAS exposure.

Table 52 presents the calculated HI for all combined cumulative pathways for the upper range exposure scenarios, for residents, excluding those subject to the above precautionary recommendations. These HI are all less than the target value of 1, indicating that where the precautionary recommendations are followed it is unlikely that a person living in the IA would exceed the TDI.



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Table 52 Summary of Estimated Hazard Indices (excluding pathways subject to precautionary recommendations)

Receptor HI – Upper exposure parameters

Adult Child


Residential 0.0016 0.006

Groundwater Zone 1


Groundwater Zone 2


7.4 Risk Estimate Evaluation for Individual Pathways

As PFAS have the potential to bioaccumulate and human receptors can be exposed via multiple pathways, a cumulative risk assessment has been undertaken involving the addition of the hazard quotients for each chemical and exposure pathway relevant to a particular human receptor.

This HHRA considers a large number of exposure pathways that may not be applicable to every individual. Therefore, the following discussion has been prepared to provide an evaluation of the individual pathways contributing to the estimated total HI.

Where the total cumulative HI for all pathways is less than the target value of 1, it is considered that cumulative exposure via all pathways is low and it is not expected that adverse health effects would occur.

Where the total cumulative HI for all pathways exceeds the target value of 1, the outcomes of the HHRA have been used to identify which pathways contribute that most to the total HI and therefore can be managed to most effectively reduce exposure to PFAS in the future (as recommended by Queensland Health). The HHRA adopted a HQ greater than 0.5 as a basis to identify individual pathways with elevated PFAS exposure.

The calculated HQ presented for each exposure pathway is the sum of the HQ for PFOS, PFOA, PFHxS and PFHxA, as appropriate. Individual HQs for each CoPC are presented in Appendix J (it is noted that the HQ for PFOS and PFHxS should be considered cumulatively, in accordance with the approach adopted by FSANZ, 2017).

7.4.1 Intakes Based on Typical Exposure Parameters

Typical exposure assumptions were based on mean or median parameters for the general population. These values were intended to capture the typical and average exposure for the majority of the population, based on a combination of ‘common sense’ professional judgement and published values regarding exposure frequency and PFAS ingestion. It is anticipated that the assessment of the typical scenario will be applicable to the majority of the population. The typical exposure assumptions have been coupled with maximum EPC for soil, groundwater, sediment, surface water, chicken eggs and livestock blood and milk, resulting in HHRA outcomes that are considered to be conservative and overestimate rather than underestimate potential PFAS exposure.

Intakes of groundwater used for drinking water supply, based on typical amounts of water consumed per day, were estimated to exceed the TDI in Groundwater Zone 1 and Zone 2. A precautionary approach for this pathway would be to continue to follow the advice not to use groundwater for drinking water supply in Groundwater Zone 1 and Zone 2 (including water used for cooking).

The estimated HI based on typical exposure parameters in Table 50 are less than the target value of 1 for the following receptors:

residents in Groundwater Zone RoIA



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commercial agriculture workers in Groundwater Zone RoIA and Zone 1

recreational users of publicly accessible areas including playing fields and local waterways (all Groundwater Zones in the IA)

on-Site personnel.

This is considered to indicate that people who live outside the IA would not be likely to have PFAS intakes exceeding the TDI adopted in this HHRA if their only exposures are to environmental impacts while undertaking work or recreation activities within the IA.

The estimated HI for residents in Groundwater Zone RoIA, based on typical exposure parameters, is less than the target HI of 1. This is considered to indicate that the average person living within Groundwater Zone RoIA would not be likely to have PFAS intakes exceeding the TDI adopted in this HHRA. Further, intakes of groundwater used for drinking water supply based on typical amounts of water consumed per day were below the TDI in Groundwater Zone RoIA, which indicates that at these intake rates groundwater could theoretically be used for drinking or food preparation purposes in Groundwater Zone RoIA. Notwithstanding this, the precautionary advice from Queensland Health to not consume or use groundwater for food preparation should still be observed by residents in the Groundwater Zone RoIA based on changes in PFAS concentration in groundwater over time.

The estimated HI for commercial agricultural workers based on typical exposure parameters are less than the target value of 1 for Groundwater Zone RoIA and Zone 1, which indicate that the average agricultural worker would not be likely to have PFAS intakes exceeding the TDI.

The estimated cumulative HI in Table 51, based on typical exposure parameters for residents in Groundwater Zone RoIA who also undertake work or recreation activities in the RoIA, are also less than the target HI of 1. This is considered to indicate that PFAS intakes are unlikely to exceed the TDI in the event that residents also have exposure to PFAS as a result of the identified exposure pathways associated with commercial agriculture activities or recreation activities in publicly accessible areas including playing fields and local waterways.

The estimated HI based on typical exposure parameters exceeds the target value of 1 for residents in Groundwater Zone 1 and Zone 2 and commercial agricultural workers in Groundwater Zone 2.

The pathway primarily contributing to the estimated intakes for commercial agricultural workers in Groundwater Zone 2 was the ingestion of home grown red meat, which contributed to 99% to 100% of the total HI for this scenario.

The pathways that have been identified to individually result in estimated intakes greater than the TDI for residents in Groundwater Zone 1 and Zone 2, and the elevated risk pathways for cumulative exposure which contribute to the exceedance of the TDI for residents based on typical range exposure parameters, are presented in Table 53.

Table 53 Elevated PFAS exposure pathways based on typical exposure parameters

Groundwater Zones

Individual Pathways Exceeding TDI (HQ>1)

Individual Pathways (HQ>0.5) Contributing to Cumulative Exposure above TDI

Residents in Groundwater Zone 1

Ingestion of groundwater used for drinking water or in cooking

Ingestion of home grown poultry eggs



Ingestion of home grown livestock milk


Ingestion of home grown leafy green vegetables

Ingestion of home grown red meat (from beef or lamb)

Incidental ingestion of groundwater used in home swimming pools

Incidental ingestion of groundwater during showering/bathing



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The potential for increased PFAS intakes in association with upper range exposure parameters is discussed in Section 7.4.2.

7.4.2 Intakes Based on Upper Range Exposure Parameters

Upper range exposure parameters were selected to be representative of a reasonable maximum exposure (RME) for people who undertake activities at a higher frequency or ingest more than the average person. These scenarios provide an estimate of exposure that is reflective of the upper/high end of the scale. It is considered that the exposure frequency and quantity assumed by the upper range parameters will only apply to a small percentage of the population (e.g. a number of the adopted exposure parameters are based on the 95th percentile from published Australian studies).

Intakes of groundwater used for drinking water supply based on upper range water ingestion rates (i.e. 5 L/day for adults and 0.9 L/day for children) were estimated to exceed the TDI. As discussed in Section 7.2, a precautionary approach would be to continue to follow the advice from Defence and the Queensland Government not to use groundwater for drinking water supply within the IA (including water used for cooking). Therefore, the estimated HI discussed below exclude the drinking water pathway.

The estimated HI in Table 50 for residents in Groundwater Zone RoIA based on upper range exposure parameters are less than the target HI of 1. This is considered to indicate that residents living within the Groundwater Zone RoIA would not be likely to have PFAS intakes exceeding the TDI adopted in this HHRA, provided that they continue to follow the precautionary recommendation to not use groundwater within the IA for drinking purposes.

The estimated HI for commercial agricultural workers in Groundwater Zone RoIA are less than the target HI of 1, which indicates that commercial agricultural workers in Groundwater Zone RoIA would not be likely to have PFAS intakes exceeding the TDI, even at upper range exposure to environmental PFAS impacts.

The estimated HI for people who live outside the IA and undertake work on-Site, based on upper range exposures to environmental PFAS impacts, would not be likely to have PFAS intakes exceeding the TDI adopted in this HHRA.

The estimated HI based on upper range exposure parameters exceeds the target value of 1 for residents in all Groundwater Zone 1 and Zone 2. This indicates that there is the potential for PFAS intakes (in particular, PFOS and PFHxS) to exceed the TDI in circumstances where groundwater is used for drinking water supply or the resident has particularly higher rates of incidental ingestion of groundwater containing the maximum concentrations of PFAS, and upper range rates of ingestion of produce that have been grown with groundwater containing detectable concentrations of PFAS.

The estimated HI for commercial agricultural workers exceed the target value of 1 for Groundwater Zone 1 and Zone 2, which indicates the potential for PFAS intakes to exceed the TDI where the agricultural worker has particularly higher rates of ingestion of red meat from livestock that have been exposed to groundwater containing detectable concentrations of PFAS.

The estimated HI based on upper range exposure parameters for recreational users of local waterways exceed the target value of 1 for the entire IA (all groundwater zones). This indicates there is potential for PFAS intakes to exceed the TDI where the people who undertake recreational activities have particularly higher rates of ingestion of fish and yabbies that have been exposed to surface water containing detectable concentrations of PFAS.

The risk driving pathways that have been identified to individually result in estimated intakes greater than the TDI for residents in Groundwater Zone 1 and Zone 2, and the elevated risk pathways for cumulative exposure which contribute to the exceedance of the TDI for residents based on upper range exposure parameters, are presented in Table 55.



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Table 54 Elevated PFAS exposure pathways based on upper range exposure parameters

Groundwater Zones

Individual Pathways Exceeding TDI (HQ>1)

Individual Pathways (HQ>0.5) Contributing to Cumulative Exposure above TDI

Residents in Groundwater Zone RoIA

Ingestion of groundwater used for drinking water or in cooking.

None *




High intake rates of home grown red meat (from beef or lamb)


Ingestion of home grown eggs.


Incidental ingestion of groundwater during sprinkler play.




Incidental ingestion of groundwater during sprinkler play


High intake rates of home grown red meat (from beef or lamb)



Ingestion of home grown eggs

None

* Although the HQ of 0.54 for consumption of eggs from backyard poultry by a child slightly exceeds 0.5, none of the other pathways (excluding drinking water) approaches a HQ of 0.5, therefore cumulative exposure is not considered likely to be a significant risk driver in this area.

These upper range scenarios warrant a more detailed discussion of the pathways that contribute most significantly to the estimated intakes. This is presented in Section 7.5 below.

The estimation of theoretical upper range intakes in excess of the TDI does not necessarily mean that health effects will be realised. A number of the pathways that contribute to these upper range intakes for residents are currently being managed by providing water assistance to residents on a case-by-case basis for drinking. In some cases this has extended to provision of an alternative water supply to laundries, kitchens and swimming pools. Further, if all the precautionary measures outlined in Section 4.8.3 were followed, the estimated cumulative HI in Table 52, based on upper range exposure parameters for residents in all three groundwater zones, would be less than the target HI of 1. This is considered to indicate that an Oakey resident living within the IA (with typical or upper range exposures) would not be likely to have PFAS intakes exceeding the TDI adopted in this HHRA, provided that they follow all the precautionary recommendations as outlined by Queensland Health.



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7.5 Relative Contribution of Individual Pathways

As discussed in Section 3.4, the identification of the relative contribution to the overall risk estimate from each exposure pathway is an outcome of the HHRA relevant to subsequent risk management decisions.

As discussed in Section 7.4.1 and Section 7.4.2, there is the potential for the total HI to exceed the target value of 1 under circumstances where the identified exposure pathways (excluding consumption of groundwater) all occur together under the exposure scenarios assessed for the following receptors:

Typical Exposure Parameters (excluding drinking groundwater)


Residents in Groundwater Zone 2.

Upper Range Exposure Parameters (excluding drinking groundwater)



Commercial agricultural workers in Groundwater Zone 1

Commercial agricultural workers in Groundwater Zone 2.

To assist with identifying the non-drinking water exposure pathways that contribute most to these estimated cumulative intakes for the receptors, the contribution of the individual exposure pathways (excluding drinking water) to the total HI, based on the adopted exposure parameters, has been represented graphically for each receptor in the following figures:

Figure 5 HI breakdown by exposure pathway for Residents in Groundwater Zone 1 – Typical exposure scenario (excluding drinking groundwater)

Figure 6 HI breakdown by exposure pathway for Residents in Groundwater Zone 2 – Typical exposure scenario (excluding drinking groundwater)

Figure 7 HI breakdown by exposure pathway for Residents in Groundwater Zone 1 – Upper range exposure scenario (excluding drinking groundwater)

Figure 8 HI breakdown by exposure pathway for Residents in Groundwater Zone 2 – Upper range exposure scenario (excluding drinking groundwater).

The pathways (and associated HI) represented in these figures exclude use of groundwater for drinking.

It is noted that the percentages that each pathway are reported to contribute to the overall HI are based on a single set of parameters, adopted to reflect either a typical or an upper exposure scenario for each Groundwater Zone. In reality, a range of exposures can be expected, which would result in variability between individuals in the relative contribution of each pathway to overall intakes.

Figure 5 to Figure 8 provide information regarding the relative contribution of each pathway, and demonstrate that a limited number of pathways are likely to account for the majority of PFAS intake.

A summary of the exposure pathways which, combined, contributed to more than 75% of the estimated HI (in variable proportions, depending on the groundwater zone and receptor age group), based on typical and upper range exposure parameters for residents and commercial agricultural workers, is presented in Table 55, Table 56, Table 57 and Table 58. These pathways are important for further consideration in future risk management decisions.



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Figure 6 HI breakdown by exposure pathway for residents in Groundwater Zone 1 – typical exposure scenario (excluding drinking groundwater)



136

Figure 7 HI breakdown by exposure pathway for residents in Groundwater Zone 2 – typical exposure scenario (excluding drinking groundwater)



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Figure 8 HI breakdown by exposure pathway for residents in Groundwater Zone 1 – upper range exposure scenario (excluding drinking groundwater)



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Figure 9 HI breakdown by exposure pathway for residents in Groundwater Zone 2 – upper range exposure scenario (excluding drinking groundwater)



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Table 55 Identified significant pathways for typical range exposures – residents (excluding drinking groundwater)

Pathway

Resident, Groundwater Zone 1 Resident, Groundwater Zone 2

Comments Adult HI

(% of total HI)

Child HI

(% of total HI)

Adult HI

(% of total HI)

Child HI

(% of total HI)


0.34

(59%)

0.77

(52%)

2.0

(44%)

4.7

(35%)

The potential range of concentrations in eggs was estimated by calculating the chronic daily intake (CDI) of PFAS by chickens and applying a transfer factor into eggs. The laying rate and average weight of the edible portion of the eggs were parameters used to calculate the concentration in eggs.

Minimising consumption of home grown eggs from poultry that drink groundwater with detectable PFAS concentrations in Groundwater Zone 1 and Zone 2 is currently recommended as a precautionary measure. Because the HI for Groundwater Zone RoIA exceeded 0.5 for upper range exposures via ingestion of backyard poultry eggs, this precautionary measure should also be considered within Groundwater Zone RoIA.


0.11

(19%)

0.20

(14%)

0.79

(17%)

1.5

(11%)

The potential range of concentrations in the edible portion of leafy green vegetables was estimated by multiplying the groundwater EPC for each Groundwater Zone by a theoretical TF. It is noted that this approach estimated significantly higher concentrations of PFAS in leafy green vegetables than have been measured in the samples collected from the IA. It is considered that this is due to uncertainties and conservatism associated with applying a TF from plants grown under controlled experimental conditions to plants grown under ambient environmental conditions with a wider range of environmental variables (e.g. rainfall).

Minimising consumption of home grown leafy greens grown in areas that are currently or were historically irrigated with groundwater with detectable PFAS concentrations is currently recommended as a precautionary measure in Groundwater Zone 1 and Zone 2.



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Pathway


Comments Adult HI

(% of total HI)

Child HI

(% of total HI)

Adult HI

(% of total HI)

Child HI

(% of total HI)

Ingestion of home grown red meat

0.08

(14%)

0.18

(12%)

1.3

(27%)

2.9

(22%)

The data set used in this assessment consisted of 18 blood serum samples collected from two properties located in Groundwater Zone 1.

No locations for cattle blood serum sampling were identified in Groundwater Zone 2. As such, the PFAS concentrations in cattle blood serum were theoretically estimated based on measured maximum cattle intakes of soil and groundwater, and adopting the simple first order one compartment steady state pharmacokinetic model described in Appendix G20.

Until additional data can be collected to further characterise PFAS concentrations in livestock blood serum at a range of groundwater PFAS concentrations in the IA, minimising consumption of home grown red meat from livestock that drink groundwater with detectable PFAS concentrations is currently recommended as a precaution.




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Pathway


Comments Adult HI

(% of total HI)

Child HI

(% of total HI)

Adult HI

(% of total HI)

Child HI

(% of total HI)


0.0058

(1%)

0.053

(4%)

0.25

(5%)

2.2

(17%)

This assessment was based on a limited data set of five samples, collected from livestock located on one property in Groundwater Zone 1.

No locations for cow milk sampling were identified in Groundwater Zone 2. Hence, the PFAS concentrations in cow milk were estimated based on the theoretical PFAS concentrations in cattle blood serum, the measured maximum intakes of soil and groundwater, and adopting the empirical blood serum to milk transfer factors to estimate theoretical maximum cow milk PFAS concentrations.

Until additional data can be collected to further characterise PFAS concentrations in livestock milk at a range of groundwater PFAS concentrations in the IA, minimising consumption of home grown milk from livestock that drink groundwater with detectable PFAS concentrations is recommended as a precaution.


0.01 (2%)

0.10 (7%)

0.09 (2%)

0.71 (5%)

Since July 2014, Defence has provided assistance for residents on a case-by-case basis to access an alternative water supply, including for household purposes and for domestic swimming pools that had previously been topped up with groundwater. Therefore, this pathway may not necessarily be complete for all people in the IA.



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Table 56 Identified significant pathways for typical range exposures – commercial agricultural workers

Pathway

Commercial Agricultural Workers, Groundwater Zone 1


Comments Adult HI (% of total HI)

Child HI (% of total HI)

Adult HI (% of total HI)

Child HI (% of total HI)


0.20 0.45 1.5 3.5 The data set used in this assessment consisted of 18 blood serum samples collected from two properties located in Groundwater Zone 1. No locations for cattle blood serum sampling were identified in Groundwater Zone 2. As such, the PFAS concentrations in cattle blood serum were theoretically estimated based on measured maximum cattle intakes of soil and groundwater, and adopting the simple 1st order one compartment steady state pharmacokinetic model described in Appendix G20. Until additional data can be collected to further characterise PFAS concentrations in livestock blood serum at a range of groundwater PFAS concentrations in the IA, minimising consumption of home grown red meat from livestock that drink groundwater with detectable PFAS concentrations is currently recommended as a precaution. The assessment of ingestion of home grown red meat has been based on PFAS concentrations estimated in muscle tissue. It is noted that higher concentrations of PFAS are likely to be encountered in offal such as liver and kidneys compared to muscle tissue, and therefore the conclusions of this HHRA in regard to consumption of red meat also apply to consumption of offal.

(99%) (100%) (99%) (100%)



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Table 57 Identified significant pathways for upper range exposures – residents (excluding drinking groundwater)

Pathway


Comments Adult HI

(% of total HI)

Child HI

(% of total HI)

Adult HI

(% of total HI)

Child HI

(% of total HI)

Ingestion of home grown eggs

1.9 7.1 12 43 The potential range of concentrations in eggs was estimated by calculating the chronic daily intake (CDI) of PFAS by chickens and applying a transfer factor into eggs. The laying rate and average weight of the edible portion of the eggs were parameters used to calculate the concentration in eggs.

Minimising consumption of home grown eggs from chickens that drink groundwater with detectable PFAS concentrations in Groundwater Zone 1 and Zone 2 is currently recommended as a precaution.

(39%) (49%) (27%) (34%)


1.1

(22%)

2.3

(16%)

8.0

(19%)

16.5

(13%)

The potential range of concentrations in the edible portion of leafy green vegetables was estimated by multiplying the groundwater EPC for each Groundwater Zone by a theoretical TF. It is noted that this approach estimated significantly higher concentrations of PFAS in leafy green vegetables than have been measured in the samples collected from the IA. It is considered that this is due to uncertainties and conservatism associated with applying a TF from plants grown under controlled experimental conditions to plants grown under ambient environmental conditions with a wider range of environmental variables (e.g. rainfall).

Minimising consumption of home grown leafy greens grown in areas that are currently or were historically irrigated with groundwater with detectable PFAS concentrations is currently recommended as a precautionary measure in Groundwater Zone 1 and Zone 2.



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Pathway


Comments Adult HI

(% of total HI)

Child HI

(% of total HI)

Adult HI

(% of total HI)

Child HI

(% of total HI)


1.0 2.5 17 39 The data set used in this assessment consisted of 18 blood serum samples collected from two properties located in Groundwater Zone 1.




(21%) (17%) (39%) (32%)



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Pathway


Comments Adult HI

(% of total HI)

Child HI

(% of total HI)

Adult HI

(% of total HI)

Child HI

(% of total HI)


0.57 1.3 4.2 9.4 Since July 2014, Defence has provided assistance for residents on a case-by-case basis to access an alternative water supply, including for household purposes and for domestic swimming pools that had previously been topped up with groundwater. Therefore, this pathway may not necessarily be complete for all people in the IA.

(12%) (9%) (10%) (8%)

Incidental ingestion of groundwater used for showering/bathing

0.12 0.69 0.91 5.1

(3%) (5%) (2%) (4%)


0.01 0.15 0.56 6.4 This assessment was based on a limited data set of five samples, collected from livestock located on one property in Groundwater Zone 1.

No locations for cow milk sampling were identified in Groundwater Zone 2. Hence, the PFAS concentrations in cow milk were estimated based on the theoretical PFAS concentrations in cattle blood serum, the measured maximum intakes of soil and groundwater, and adopting the empirical blood serum to milk transfer factors to estimate theoretical maximum cow milk PFAS concentrations.

Until additional data can be collected to further characterise PFAS concentrations in livestock milk at a range of groundwater PFAS concentrations in the IA, minimising consumption of home grown milk from livestock that drink groundwater with detectable PFAS concentrations is recommended as a precaution.

(0.3%) (1%) (1%) (5%)



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Table 58 Identified significant pathways for upper range exposures – commercial agricultural workers

Pathway



Comments Adult HI

(% of total HI)

Child HI

(% of total HI)

Adult HI

(% of total HI)

Child HI

(% of total HI)


1.8 4.1 13 32 The data set used in this assessment consisted of 18 blood serum samples collected from two properties located in Groundwater Zone 1.




(96%) (100%) (98%) (100%)



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7.6 Assessment of Human Blood Serum Data

As an additional line of evidence, the 2016 HHRA included an assessment undertaken by ToxConsult (2016c) of the potential for health effects based on PFAS concentrations in human blood.

The assessment was based on measured and modelled blood PFAS concentrations and did not utilise the TDI described in Section 6.2. Rather, it involved comparison directly to a human blood serum NOAEL derived by ToxConsult, and published NOAEL or LOAEL derived from animal experiments. A detailed interpretation of findings from the assessment is described in the 2016 HHRA and a brief summary is presented below.

Measured PFAS concentrations in blood of 75 people from Oakey did not indicate that adverse health effects are likely to occur.

Based on potential modelled PFAS concentrations in blood, there were theoretical upper range exposure scenarios where PFAS exposure due to consumption of red meat, liver or fish could exceed tolerable limits. Measured concentrations of PFAS in blood did not indicate that these theoretical scenarios have been realised.

PFAS concentrations in blood were elevated above typical background concentrations for people in Australia. Minimising future PFAS exposure by observing precautionary recommendations will result in blood PFAS concentrations declining over time.

7.7 Summary

The weight of evidence from the above is considered to indicate, based on the available data, that there is a low and acceptable risk to health associated with typical exposure to the Site-derived PFAS in the environment (excluding use of groundwater for drinking or in cooking) for:

residents within Groundwater Zone RoIA

residents within Groundwater Zone 1 who do not consume home-grown food

commercial agriculture workers and their families in Groundwater Zone 1 and Zone RoIA

commercial agriculture workers and their families in Groundwater Zone 2 who do not consume home-grown food from the properties they work on

recreational users of local waterways in the entire IA who undertake activities such as boating, fishing (including consumption of fish that are caught) and swimming in local waterways

on-Site personnel.

There are theoretical scenarios where typical and upper range exposures could result in PFAS intakes that exceed the TDI. ToxConsult (2016c) concluded that the available blood serum data from the Oakey cohort (Heffernan, 2015) indicate that these elevated PFAS exposures are unlikely to have occurred, although this cannot be stated with certainty.

In consideration of the theoretical scenarios that could be associated with PFAS intakes that exceed the TDI, the data gaps and uncertainties inherent in these assessments and that people from Oakey have elevated blood PFAS concentrations due to past exposure5, a precautionary approach would be to minimise future PFAS exposure, as recommended by Queensland Health.

The pathways identified in this HHRA with the greatest potential for PFAS exposure (refer to Section 7.3) are consistent with the pathways that Queensland Health has previously advised be avoided or minimised (https://www.qld.gov.au/environment/pollution/management/incidents/oakey). The HHRA outcomes have been used to identify which aspects of the existing general advice from Queensland Health may be followed to most effectively minimise PFAS exposure in the future, including:

5 ToxConsult, 2016c. HHRA for the Army Aviation Centre Oakey using PFAS serum considerations. Tox Consult document ToxCR230616-TF, 19 August, 2016



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Not using groundwater for drinking water supply (including water used for cooking). This is considered to be relevant to all users of groundwater in Groundwater Zone 2 and Zone 1. The HHRA outcome indicates that PFAS exposure via drinking groundwater would be low and acceptable under typical exposure scenarios in the Groundwater Zone RoIA. Further, the FSANZ (2017) drinking water guideline values could be used to identify specific locations where the PFAS concentrations in groundwater are acceptable for drinking. However, because Queensland Health recommends that residents that live in or near a contaminated area reduce exposure to PFAS, and because the HHRA has estimated that residents’ PFAS exposure via drinking groundwater would be greater than for all other pathways combined, it is suggested that as a precautionary measure residents continue not to use groundwater for drinking or in cooking in Groundwater Zone RoIA.

Avoiding the use of groundwater containing detectable concentrations of PFAS for showering/bathing, sprinklers or to fill swimming pools or paddling pools, due to the potential for PFAS intake via incidental ingestion. This is considered to be relevant to residents in Groundwater Zone 2. Residents in Groundwater Zone 1 should minimise the use of groundwater containing detectable concentrations of PFAS in order to avoid the upper range exposures (typical exposures via these pathways in Groundwater Zone 1 were identified to be associated with low and acceptable PFAS intake).

Avoiding consumption of home grown eggs from backyard poultry that have exposure to PFAS in the environment. This is considered to be relevant to residents in Groundwater Zone 2, and it is suggested that residents in Groundwater Zone 1 should minimise consumption of home grown eggs in order to avoid the upper range exposures assessed in this HHRA (typical exposures via this pathway in Groundwater Zone 1 were identified to be associated with low and acceptable PFAS intake).

Avoiding consumption of home grown green vegetables that have exposure to PFAS in the environment. This is considered to be relevant to residents in Groundwater Zone 2, and it is suggested that residents in Groundwater Zone 1 should minimise consumption of home grown leafy green vegetables in order to avoid the upper range exposures assessed in this HHRA (typical exposures via this pathway in Groundwater Zone 1 were identified to be associated with low and acceptable PFAS intake).

Until additional data can be collected to further characterise PFAS concentrations in home grown red meat and cow milk at a range of PFAS concentrations in the IA, avoiding consumption of:

- Home grown red meat or offal from livestock that that have exposure to PFAS in the environment. This is considered to be relevant to residents in Groundwater Zone 2, and it is suggested that residents in Groundwater Zone 1 should minimise consumption of home grown red meat or offal in order to avoid the upper range exposures assessed in this HHRA (typical exposures via this pathway in Groundwater Zone 1 were identified to be associated with low and acceptable PFAS intake).

- Home grown milk from livestock that have exposure to PFAS in the environment. This is considered to be relevant to residents in Groundwater Zone 2.

Minimising consumption of fish caught from Oakey Creek.



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8.0 Uncertainty Evaluation and Sensitivity Assessment

8.1 Uncertainties

The risk assessment process involves a number of assumptions regarding Site conditions, human exposure and chemical toxicity. These assumptions are based on Site-specific information (where available), but it is not always possible to fully predict or describe environmental conditions and human activities at a site for the exposure period considered in the risk assessment. The assumptions adopted in this risk assessment have therefore been selected to cover two exposure scenarios: average exposure; and, to be conservative in nature, an assumed reasonable maximum upper scenario which provides a deliberate margin of safety for the average person.

The key uncertainties associated with components of the risk assessment process include:

sampling and analysis – consideration of identified data gaps and whether collection of further data is warranted to further reduce the uncertainty in the exposure modelling and sampling. The HHRA has typically adopted conservative assumptions to deal with the data gaps discussed in Section 4.2.4. Where additional data are collected in the future, the HHRA outcomes can be further refined

human exposure parameters – consideration of potential variability of exposure parameters based on available Site-specific information, and whether further survey of residents may be required to reduce the uncertainty in the exposure modelling

toxicity assessment – consideration of the uncertainty associated with the derivation of adopted TRV.

Conservative assumptions (i.e. likely to overestimate actual conditions) have been made in the selection of parameters for use in the HHRA based on the available information. These are intended to reduce the potential for underestimation of the extent or concentration of PFAS in the IA.

It is stressed that the nature and extent of PFAS detections described in this report are not intended to be a definitive description. Rather, they provide a ‘snapshot’ of conditions when the samples were taken. Understanding of the nature and extent of impacts will continue to evolve as additional data are collected that refine the spatial coverage and provide an improved understanding of the range of concentrations that might be encountered.

The data gaps discussion in Section 4.2.4 summarises some of the key uncertainties associated with the data that have been presented in this report, and the steps taken in the HHRA to minimise the impacts of this variability on the resultant conclusions. The sensitivity of the HHRA outcomes to some of the key sources of uncertainty are discussed in the following section, along with the plausible ranges for each of the key quantifiable uncertainties.

8.2 Potential Future Uses of Water for Aquaculture

It is understood that no private aquaculture systems are currently present in the IA. Under the Environmental Protection Act 1994, environmental values including potential uses of abstracted water are protected, even if they are not currently occurring. Therefore, to address potential future land use changes, the consumption of fish raised in a future aquaculture system has been assessed as part of an uncertainty analysis.

To assess the potential risk to human health via ingestion of fish raised in a future aquaculture system, AECOM has compared estimated PFAS concentrations in fish to the maximum allowable PFAS concentrations before the TDI is reached (later referred to as ‘trigger points’) as published by FSANZ (2017a). The trigger points determined by FSANZ (2017a) were based on median consumption rates for freshwater fish (i.e. 28 g/day for a child and 56 g/day for an adult). The FSANZ (2017a) trigger points are presented in Table 59.



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Table 59 Maximum PFAS concentrations at median consumption (consumers only) to reach TDI

CoPC Trigger Points – Freshwater Fish (mg/kg)

Child 26 years Trigger Points – Freshwater Fish (mg/kg)

Adult 2+ years

PFOS 0.02 0.033

PFOA 0.158 0.267

PFHxS 0.02 0.033

PFHxA Not available Not available

As no trigger point was available for PFHxA, it has not been further assessed as part of this uncertainty assessment.

In the absence of measured fish tissue data from an aquaculture system in the IA, the concentration of PFAS in fish tissue has been calculated using the following equation (EA, 2011 and US EPA, 1996):

BAFCC wfish

Where:

Cfish = Estimated concentration of PFAS in fish (mg/kg)

Cw = Measured concentration of PFAS in water (mg/L)

BAF = Fish bioaccumulation factor (BAF) (L/kg) (sourced from CRC CARE, 2017)

The ingestion of fish pathway was conservatively assessed assuming that fish raised in an aquaculture system were exposed to the maximum PFAS concentrations detected in groundwater or surface water within each Zone of the IA.

The BAF is the ratio of the contaminant concentration in fish to the contaminant concentration in the water column where the fish is exposed (BAF = Cfish/Cwater, Kwadijk et al. 2014). It accounts for uptake of contaminants by fish from water passing across the gills. As stated in CRC CARE (2017) ‘There is insufficient data to support the setting of bioaccumulation factors relevant to Australian biota, and in the absence of such data, it has been considered appropriate to adopt the RIVM factors.’ Therefore, in accordance with the approach adopted by CRC CARE (2017), AECOM has adopted the geometric mean of the BAF values in freshwater species from the Dutch National Institute for Public Health and the Environment (RIVM, 2010) data for PFOS and PFOA as presented in Table 60. It is noted that the BAF for PFOS was applied to the sum of PFOS and PFHxS by CRC CARE (2017) and as such, AECOM has adopted the BAF published for PFOS for PFHxS. It is noted that the CRC CARE (2017) approach is from a draft report, and this assessment may therefore need to be revisited in the future if a different approach is adopted by CRC CARE in its final report.

The estimated PFAS concentrations in fish, based on measured PFAS concentrations in groundwater/surface water and published BAF, are presented in Table 60. The estimated PFAS concentrations in fish reported to be above the FSANZ (2017a) trigger points (as presented in Table 59) are highlighted in bold.

Table 60 Concentrations of PFAS in fish

CoPC Measured Water

Concentration (mg/L) Fish Bioaccumulation

Factor (BAF) (L/kg)

Estimated PFAS Concentration in Fish

(mg/kg)

Groundwater Zone 1

PFOS 0.00491 12,900 63.34

PFOA 0.00081 12,900 10.45

PFHxS 0.00502 12,900 64.76



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CoPC Measured Water

Concentration (mg/L) Fish Bioaccumulation

Factor (BAF) (L/kg)

Estimated PFAS Concentration in Fish

(mg/kg)

Groundwater Zone 2

PFOS 0.0398 12,900 513.42

PFOA 0.00203 12,900 26.19

PFHxS 0.033 12,900 425.70


PFOS 0.00008 12,900 1.03

PFOA 0.00005 12,900 0.65

PFHxS 0.00027 12,900 3.48

Surface Water (all Groundwater Zones)

PFOS 0.0023 12,900 29.67

PFOA 0.00019 12,900 2.45

PFHxS 0.00026 12,900 3.35

Notes: Bold text indicates an exceedance of the FSANZ (2017a) maximum PFAS concentrations to reach the TDI.

As shown in Table 60, the estimated PFAS concentrations in fish would exceed the FSANZ (2017a) trigger points if fish raised in an aquaculture system were exposed to the maximum PFAS concentrations detected in groundwater and surface water in each Zone of the IA. This indicates that there is a potentially unacceptable risk to human health via ingestion of fish (at the median level of consumption for the Australian population) from an aquaculture system if groundwater or surface water within the IA is used. Based on this outcome, the potential risk to human health should be further evaluated based on Site-specific data before any aquaculture is undertaken in the IA in the future.

However, AECOM notes that this assessment is conservative and the estimated PFAS concentrations in fish tissue may not be realised, based on the following:

The FSANZ (2017a) trigger points were based on median consumption rates for freshwater fish (i.e. 28 g/day for a child and 56 g/day for an adult). These consumption rates are higher than those adopted in the HHRA (16.4 g/day for a child and 32.8 g/day for an adult under an upper exposure scenario) and are significantly higher than the average consumption rates published by NNPAS (ABS, 2014); i.e. 3.6 g/day for a child (2-3 years old) and 10.3 g/day for adults (51-70 years old).

It was assumed that fish were exposed to maximum PFAS concentrations in groundwater and surface water. However, fish are likely to be exposed to varied concentrations of PFAS in water over their lifetime.

The BAF for freshwater fish ranged from 2,500 L/kg to 95,000 L/kg (RIVM, 2010) with the geometric mean of the BAF values being 12,900 L/kg. This value is based on laboratory studies and assumes that the laboratory-measured bioaccumulation applies to organisms lower in the food chain and subsequent biomagnification at higher trophic levels in the food chain. As stated in CRC CARE (2017), ‘Field-derived BAF values for fish could provide a more direct indication of the concentration of PFOS that result from the concentration of PFAS measured in water or sediment’. Therefore, the adopted BAF is likely to overestimate the bioaccumulation potential of PFAS into fish in the environment. There is some evidence that the longer chain PFCAs may bioaccumulate to a greater degree than PFOS, however currently there is no Australian guidance



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on how other PFAS should be assessed, and TRV for use in Australian HHRA are not available for other PFAS. It is noted that the maximum PFOS, PFHxS and PFOA concentrations reported in fish samples from the IA (1.6 mg/kg, 0.013 mg/kg and 0.0027 mg/kg, respectively) are at least an order of magnitude lower than those estimated in Table 60, except for the concentrations estimated based on groundwater in Groundwater Zone RoIA.

8.3 Sensitivity Assessment

The identified key uncertainties related to the estimated intakes and resulting HI, and the manner in which they were addressed in the HHRA, are presented in Table 61.

The sensitivity assessment explores the effect of varying selected HHRA input parameters, one at a time, on the estimated HI for a resident in the Groundwater Zone 1 scenario based on typical exposure parameters (unless otherwise stated). This scenario represents the average person living within the IA being exposed to a PFOS concentration in groundwater that is in the upper 10th percentile of all concentrations reported in groundwater in the IA.



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Table 61 Sensitivity assessment

Value adopted in the HHRA (range)

Value adopted in the Sensitivity Assessment

Assumption used in HHRA Outcome of sensitivity assessment

Water ingestion rates

Adult typical exposure:

2 L/day

Range:

0.2 L/day (one glass) to 5 L/day (adults undertaking moderate work in temperate environments) (enHealth, 2012a)

Adult typical exposure:

1.2 L/day

The typical water ingestion rates adopted in the HHRA were based on the lifetime average for adults recommended by enHealth (2012a).

A sensitivity calculation was undertaken using the mean water ingestion rate reported by enHealth (2012a) for short or medium periods (not lifetime) by Australian adults.

The sensitivity assessment is presented in Appendix K1.

The estimated adult PFAS intake via ingestion of groundwater used for drinking water supply decreased in proportion to the change in water ingestion rate. The estimated PFAS intake at the lower water ingestion rate of 1.2 L/day continues to exceed the TDI.

This indicates that the HHRA conclusion would not change based on the mean water ingestion rate for adults reported by enHealth (2012a) for short or medium periods (i.e. the estimated PFAS intake continues to exceed the TDI).



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Percentage of agricultural produce sourced from the IA

Adult and child typical exposure:

Green vegetables: 21%

Eggs: 29%

Red meat: 10%

Milk: 5%

Range:

0 to 100%

Adult and child typical exposure:

All produce: 100%

The typical percentage of plant and animal produce consumed by residents in the IA was adopted based on information gathered from community surveys (refer to Appendix E).

A sensitivity calculation was undertaken assuming that all produce consumed by residents is sourced from within the IA.


HI estimated for adult residents (excluding drinking groundwater), based on the assumption that 100% of all produce is sourced from within the IA, increased from 0.6 to 2.6. The ingestion of home grown red meat and eggs remained a potentially unacceptable risk, while the ingestion of milk increased to present a potentially unacceptable risk.

The risk outcome for consumption of home grown green vegetables remained low and acceptable.

HI estimated for child residents (excluding drinking groundwater), based on the assumption that 100% of all produce is sourced from within the IA, increased from 1.5 to 6.8. The ingestion of home grown red meat, eggs and milk remained a potentially unacceptable risk. The risk outcome for consumption of home grown leafy green vegetables remained low and acceptable.

This indicates that the HHRA conclusions for the typical exposure scenario would not change where a greater percentage of food is sourced from the IA at the adopted typical ingestion rates (i.e. based on the estimated HI, cumulative intakes would exceed the TDI).

PFAS concentrations in eggs, red meat and milk were conservatively estimated based on an intake by chickens and cattle from maximum measured soil and water concentrations.

Based on the risk outcomes for the typical exposure scenario, the cumulative intakes for the upper range exposure scenario would exceed the TDI at higher ingestion rates where 100% of all produce is sourced from within the IA.



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Child body weight

Child typical exposure: 17 kg

Range (enHealth, 2012a):

01 year old: Average 5 kg

95th percentile 7 kg

23 year old: Average 15 kg


47 year old:

Average 24 kg


Child typical exposure: 7 kg The typical child body weight was adopted based on the 95th percentile of a 23 year old child, male and female combined (enHealth, 2012a).

A sensitivity calculation was undertaken using the 95th percentile body weight reported for a 01 year old, also adjusting for the proportionally reduced skin surface area of 4,500 cm2.


HI estimated for child residents based on the lower body weight (excluding drinking groundwater) increased from 1.5 to 3.5.

This indicates that, despite higher daily intake rates (expressed in mg/kg/day) for children with lower body weights, the HHRA conclusions for the typical exposure scenario would not change (i.e. based on the estimated HI, cumulative intakes would exceed the TDI).



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Exposure frequency for swimming in pools filled with groundwater

52 days/year

(0 to 365 days/year)

180 days/year The typical frequency of swimming in domestic pools adopted in the HHRA for both children and adults was consistent with the upper range of the frequency of children (aged 5–14 years) who participate in swimming (ABS 2006b, Table 16, p. 33; ABS 2009, Table 13 p. 29), adopted by enHealth (2012a) as a national population average.

A sensitivity calculation was undertaken assuming that swimming in domestic pools occurs daily for the summer and spring months of the year.


HI estimated for adult residents (excluding drinking groundwater) based on the increased exposure frequency for swimming in domestic pools slightly increased from 0.57 to 0.59.

HI estimated for child residents (excluding drinking groundwater) based on the increased exposure frequency for swimming in domestic pools increased from 1.48 to 1.68.

It is considered that HI for the upper range exposure scenario would continue to exceed a value of 1 based on the combination of maximum PFOS concentrations in groundwater, higher ingestion rates and the higher exposure frequency adopted in the sensitivity assessment.

This indicates that the HHRA conclusions would not change if the increased exposure frequency for swimming in domestic pools was adopted.



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Older child (612 year old) ingestion rates for plant and animal produce

Green vegetables: 67 g/day

(Mean 110 g/day, Median 290 g/day)

Eggs: 17 g/day


Red meat: 14.3 g/day


Milk: 0.3 L/day

(Mean 0.213 L/day, Median 0.258 L/day)

(ABS, 2014, mean for all respondents and median for consumers only)

Vegetables: 110 g/day

Eggs: 13 g/day

Red meat: 18 g/day

Milk: 0.213 L/day

The HHRA utilised the following numbers of servings for plant and animal produce:

Green vegetables: Typical value equivalent to an annual average of six standard servings per week for children.

Eggs: Typical value equivalent to an annual average of one standard serving per week for children.

Red meat: Typical value equivalent to an annual average of one standard serving per week for children.

Milk: Typical value is the mean for all persons 23 years old (ABS, 2014).

A sensitivity calculation was undertaken using the mean for all persons 612 years old (ABS, 2014).

The sensitivity assessment is presented in Appendix K5. As the ingestion pathways are typically complete within Groundwater Zone 2, this zone has been used as the base for the sensitivity assessment (typical exposure).

The estimated child HI (excluding drinking groundwater) based on typical exposure parameters decreased from 13.2 to 10.2 based on the adoption of the mean ingestion rates reported for all persons 612 years old (ABS, 2014) Although the HI was lower, this does not change the conclusions of the HHRA.

Considering that the older child has a larger body weight, it is concluded that the HI for a 23 year old child is likely to be conservative for an older child (612 years old).



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Maximum groundwater concentrations reported in the deeper aquifers (i.e. Walloon Coal Measures and Main Range Volcanics)

Maximum groundwater concentrations reported in the shallower aquifer (i.e. Oakey Alluvium) was used in the HHRA.

Groundwater Zone 1:

PFOS: 4.91 µg/L (<0.01 to 4.91 µg/L)

PFOA: 0.81 µg/L (<0.01 to 0.81 µg/L)

PFHxS: 5.02 µg/L (<0.02 to 5.02 µg/L)

PFHxA: 0.76 µg/L (<0.02 to 0.76 µg/L)

Groundwater Zone 2:

PFOS: 39.8 µg/L (0.03 to 39.8 µg/L)

PFOA: 2.03 µg/L (<0.01 to 2.03 µg/L)

PFHxS: 33 µg/L (0.03 to 33 µg/L)

PFHxA: 6.86 µg/L (<0.02 to 6.86 µg/L)

Groundwater Zone RoIA:

PFOS: 0.09 µg/L (<0.01 to 0.09 µg/L)

PFOA: 0.05 µg/L (<0.01 to 0.05 µg/L)

PFHxS: 0.27 µg/L (<0.02 to 0.27 µg/L)

PFHxA: 0.05 µg/L (<0.01 to 0.05 µg/L)

PFOS: 1.34 µg/L

PFOA: 0.02 µg/L

PFHxS: 0.11 µg/L

PFHxA: not detected

The HHRA conservatively utilised the maximum PFAS concentrations detected in groundwater from the shallower aquifer in the Oakey Alluvium. To address users of the deeper aquifers (i.e. Walloon Coal Measures and Main Range Volcanics located greater than 50 m bgl), a sensitivity assessment has been undertaken using maximum PFAS concentrations detected in groundwater from the deeper aquifers. As the maximum groundwater concentrations reported in the deeper aquifer are from the RoIA, this zone has been used as the base for the sensitivity assessment (typical exposure).


HI estimated for adult residents (excluding drinking groundwater) based on the maximum groundwater concentrations reported in the deeper aquifer increased from 0.04 to 0.12.

HI estimated for child residents (excluding drinking groundwater) based on the maximum groundwater concentrations reported in the deeper aquifer increased from 0.12 to 0.36.

Based on the magnitude of change in the HI (i.e. increase of approximately 30%), it is considered likely that the HI for the upper range exposure scenario would continue to exceed a value of 1 for a child and continue to remain below a value of 1 for an adult given the HI estimated for the upper range.



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Maximum soil concentrations reported off-Site from 0 to 3 m bgl.

Groundwater Zone 1:

PFOS: 0.07 mg/kg

PFOA: 0.0014 mg/kg

PFHxS: 0.01 mg/kg

PFHxA: 0.0008 mg/kg

Groundwater Zone 2:

PFOS: 0.18 mg/kg

PFOA: 0.0073 mg/kg

PFHxS: 0.067 mg/kg

PFHxA: 0.01 mg/kg


PFOS: 0.012 mg/kg

PFOA: 0.0007 mg/kg

PFHxS:0.0016 mg/kg

PFHxA: 0.001 mg/kg

Groundwater Zone 1:

PFOS: 0.07 mg/kg

PFOA: 0.0014 mg/kg

PFHxS: 0.01 mg/kg

PFHxA: 0.0008 mg/kg

Groundwater Zone 2:

PFOS: 0.18 mg/kg

PFOA: 0.0073 mg/kg

PFHxS: 0.067 mg/kg

PFHxA: 0.01 mg/kg


PFOS: 0.012 mg/kg

PFOA: 0.0007 mg/kg

PFHxS:0.0016 mg/kg

PFHxA: 0.001 mg/kg

The HHRA conservatively utilised the maximum PFAS concentrations detected in off-Site soil from 0 to 1 m bgl (i.e. potentially impacted by irrigation activities using PFAS impacted groundwater). As samples were collected between 0 and 3 m bgl, a sensitivity assessment has been undertaken using maximum PFAS concentrations detected in soil from all off-Site data.

In each Groundwater Zone, the maximum soil concentrations were reported in the top one metre i.e. 0 to 1 m bgl. As the maximum PFAS concentrations detected in off-Site soil from 0 to 1 m bgl were used in the HHRA, the HI estimates and risk outcomes would remain unchanged for a resident if all soil data (0 to 3 m bgl) were considered.



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Maximum soil concentrations reported off-Site 0 to 1 m bgl including the roadside surface samples

Groundwater Zone 1:

PFOS: 0.07 mg/kg (<0.0002 to 0.07 mg/kg)

PFOA: 0.0014 mg/kg (<0.0002 to 0.0014 mg/kg)

PFHxS: 0.01 mg/kg (<0.0002 to 0.01 mg/kg)

PFHxA: 0.0008 mg/kg (<0.0002 to 0.0008 mg/kg)

Groundwater Zone 2:

PFOS: 0.18 mg/kg (<0.0002 to 0.18 mg/kg)

PFOA: 0.0073 mg/kg (<0.0002 to 0.0073 mg/kg)




PFOS: 0.012 mg/kg (<0.0002 to 0.012 mg/kg)

PFOA: 0.0007 mg/kg (<0.0002 to 0.0007 mg/kg)

PFHxS:0.0016 mg/kg (<0.0002 to 0.0016 mg/kg)


Groundwater Zone 1:

PFOS: 0.08 mg/kg

PFOA: 0.0031 mg/kg

PFHxS: 0.01 mg/kg

PFHxA: 0.0031 mg/kg

Groundwater Zone 2:

PFOS: 0.19 mg/kg

PFOA: 0.0073 mg/kg

PFHxS: 0.067 mg/kg

PFHxA: 0.01 mg/kg


PFOS: 0.27 mg/kg

PFOA: 0.0007 mg/kg

PFHxS:0.03 mg/kg

PFHxA: 0.01 mg/kg

The HHRA conservatively utilised the maximum PFAS concentrations detected in off-Site soil from 0 to 1 m bgl (i.e. potentially impacted by irrigation activities using PFAS impacted groundwater). However, AECOM notes that an additional 45 surface soil samples were collected from the roadside to understand the distribution of PFAS that may have migrated by wind resuspension or by flood inundation. Therefore, a sensitivity assessment has been undertaken using maximum PFAS concentrations detected in soil from all off-Site data collected from 0 to 1 m bgl including those soil samples collected from the roadside.

The sensitivity assessment is presented in Appendix K7. As the soil concentrations are comparable for Groundwater Zone 1 and Groundwater Zone 2, the sensitivity assessment has been undertaken for Groundwater Zone RoIA (typical exposure).

Groundwater Zone 1: The PFAS concentrations detected in potentially irrigated off-Site soil samples (0 to 1 m bgl) were comparable to those off-Site roadside soil samples (0 to 1 m bgl). Therefore, the risk outcomes would remain unchanged for a resident if all off-Site soil data was considered in the HHRA.

Groundwater Zone 2: The PFAS concentrations detected in potentially irrigated off-Site soil samples (0 to 1 m bgl) were comparable to those off-Site roadside soil samples (0 to 1 m bgl). Therefore, the risk outcomes would remain unchanged for a resident if all off-Site soil data was considered in the HHRA.

Groundwater Zone RoIA: HI estimated for adult residents (excluding drinking groundwater) based on the maximum soil concentrations reported in the samples collected from 0 to 1 m bgl increased from 0.04 to 0.5.

Groundwater Zone RoIA: HI estimated for child residents (excluding drinking groundwater) based on the maximum soil concentrations reported in the samples collected from 0 to 1 m bgl increased from 0.1 to 1.4.

This indicates that the HHRA conclusions would change for this Zone if residents in the RoIA had daily direct contact exposure to off-Site soil in the roadside areas. However, this is not considered likely to occur.



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Maximum seafood concentrations measured in carnivorous fish, herbivorous fish and yabbies.

All fish:

PFOS: 0.053 mg/kg (0.0037 to 1.6 mg/kg)

PFOA: 0.0023 mg/kg (<0.0003 to 0.0027 mg/kg)



Yabbies:

PFOS: 0.032 mg/kg (<0.0005 to 0.37 mg/kg)

PFOA: 0.00075 mg/kg (<0.0005 to 0.0036 mg/kg)

PFHxS: 0.0048 mg/kg (<0.0005 to 0.031 mg/kg)PFHxA: Not detected

Carnivorous fish:

PFOS: 0.25 mg/kg

PFOA: Not detected

PFHxS: 0.0022 mg/kg

PFHxA: 0.001 mg/kg

Herbivorous fish:

PFOS: 0.081 mg/kg

PFOA: 0.0018 mg/kg

PFHxS: 0.0027 mg/kg

PFHxA: Not detected

Yabbies:

PFOS: 0.37 mg/kg

PFOA: 0.0036 mg/kg

PFHxS: 0.031 mg/kg

PFHxA: Not detected

The HHRA utilised the median of detected PFAS concentrations in fish (carnivorous and herbivorous) and yabby tissue as these were considered most representative of long term dietary intakes for frequent consumers of those produce as per FSANZ (2017a) guidance.

A sensitivity assessment has been undertaken using maximum PFAS concentrations detected in fish and yabby tissue.

The sensitivity assessments are presented in Appendix K8. The ingestion of seafood is applicable to the recreational receptor.

Carnivorous fish: HI estimated for adult recreational receptors based on the maximum PFAS concentrations reported in carnivorous fish increased from 0.0035 to 0.016.

HI estimated for child recreational receptors based on the maximum PFAS concentrations reported in carnivorous fish increased from 0.0079 to 0.037.

This indicates that the HHRA conclusions would not change if maximum PFAS concentrations reported in carnivorous fish were used in the HHRA.

Herbivorous fish: The maximum PFAS concentrations detected in herbivorous fish tissue were typically equal to or less than the median PFAS concentrations. Therefore, the HI estimated for adult and child recreational receptors would be less and remain low and acceptable.

Yabbies: HI estimated for adult recreational receptors based on the maximum PFAS concentrations reported in yabbies increased from 0.00087 to 0.0095.

HI estimated for child recreational receptors based on the maximum PFAS concentrations reported in yabbies increased from 0.0015 to 0.017.

This indicates that the HHRA conclusions would not change if maximum PFAS concentrations reported in yabbies were used in the HHRA.



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Consideration of a wider range of detected PFAS in fish tissue

All fish:

PFOS: 0.053 mg/kg (0.0037 to 1.6 mg/kg)

PFOA: 0.0023 mg/kg (<0.0003 to 0.0027 mg/kg)



All yabbies

PFOS: 0.032 mg/kg (<0.0005 to 0.37 mg/kg)

PFOA: 0.00075 mg/kg (<0.0005 to 0.0036 mg/kg)


PFHxA: Not detected

All fish:

PFOS: 0.067 mg/kg

PFOA: 0.0554 mg/kg

PFHxS: 0.0018 mg/kg

PFHxA: 0.001 mg/kg

All yabbies:

PFOS: 0.0295 mg/kg

PFOA: 0.0040 mg/kg

PFHxS: 0.0048 mg/kg

The HHRA utilised the median of detected PFOS, PFOA, PFHxS and PFHxA concentrations in fish (carnivorous and herbivorous) and yabby tissue as TRV were not available for other PFAS. However, AECOM notes that other PFAS were detected in fish and yabby tissue.

Therefore, a sensitivity assessment has been undertaken to assess a wider range of PFAS intakes from consuming fish and yabbies. Specifically, the assessment was undertaken by:

Grouping perfluoroalkylsulfonic acids, FOSAs, FOSEs and FOSAAs and assessing these as equivalent in toxicity to PFOS.

Grouping PFCAs, and telomer sulfonic acids and assessing these as equivalent in toxicity to PFOA (except 4:2 telomer sulfonate and 6:2 telomer sulfonate which were assessed combined with PFHxA).

The list of PFAS groups is presented in Table 1, Appendix K9).

Summing the concentrations in each PFAS group for each aquatic biota sample refer to Table 2 and Table 3, Appendix K9).

For each of the PFAS groups, calculating a median concentration for all aquatic biota samples.


HI estimated for adult recreational receptors based on the summed sulphonate and acid median concentrations reported in all fish and yabbies slightly increased from 0.010 to 0.011.

HI estimated for child recreational receptors based on the summed sulphonate and acid median concentrations reported in all fish and yabbies slightly increased from 0.031 to 0.034.

This indicates that the HHRA conclusions would not change based on this approach to assessing the detection of a wider range of PFAS in fish and yabby tissue.



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Maximum PFAS concentrations measured in eggs from backyard poultry

The egg concentrations were estimated using egg transfer factors published by Scolexia (2017).

Groundwater Zone 1:

PFOS: 0.035 mg/kg

PFOA: 0.0014 mg/kg

PFHxS: 0.013 mg/kg

PFHxA: 0.000013 mg/kg

Groundwater Zone 2:

PFOS: 0.2 mg/kg

PFOA: 0.0038 mg/kg

PFHxS: 0.087 mg/kg



PFOS: 0.0028 mg/kg

PFOA: 0.00014 mg/kg

PFHxS:0.00084 mg/kg


Groundwater Zone 1:

PFOS:0.028 mg/kg

PFOA: Not detected

PFHxS:0.0051 mg/kg

PFHxA: Not detected

Groundwater Zone 2:

PFOS: 0.15 mg/kg

PFOA:0.00076 mg/kg

PFHxS:0.045 mg/kg

PFHxA: Not detected


PFOS:0.0037 mg/kg

PFOA: Not detected

PFHxS: Not detected

PFHxA: Not detected

The HHRA conservatively estimated PFAS concentrations in eggs by calculating the chronic daily intake of PFAS by chickens from soil and groundwater and applying transfer factors published by Scolexia (2017) into eggs.

As part of the historical and current investigations, eggs were sampled from chickens that had consumed groundwater containing detectable concentrations of PFAS and had access to soils historically irrigated with groundwater containing detectable concentrations of PFAS.

A sensitivity assessment has been undertaken using maximum PFAS concentrations detected in eggs.

The sensitivity assessments are presented in Appendix K10. As the estimated and measured egg concentrations are comparable for Groundwater Zone 1, the sensitivity assessments have been undertaken for Groundwater Zone 2 (typical exposure) and Groundwater Zone RoIA (typical exposure).

Groundwater Zone 1:

The maximum PFAS concentrations detected in eggs were typically less than the estimated PFAS concentrations. Therefore, the HI estimated for adult and child residents would decrease. However the HHRA conclusions for the typical exposure scenario would not change where measured maximum egg concentrations were used (i.e. cumulative intakes would remain above the TDI).

Groundwater Zone 2:

HI estimated for adult residents (excluding drinking groundwater) based on maximum measured egg concentrations decreased from 4.6 to 3.0. HI estimated for child residents (excluding drinking groundwater) based on maximum measured egg concentrations decreased from 13.2 to 9.4. This indicates that the HHRA conclusions for the typical exposure scenario would not change where measured maximum egg concentrations were used (i.e. cumulative intakes would remain above the TDI).


HI estimated for adult residents (excluding drinking groundwater) based on maximum measured egg concentrations was unchanged. HI estimated for child residents (excluding drinking groundwater) based on maximum measured egg concentrations was unchanged. This indicates that the HHRA conclusions for the typical exposure scenario would not change where measured maximum egg concentrations were used (i.e. cumulative intakes would remain below the TDI).



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Use of measured (median) leafy green vegetable PFAS concentrations reported in Groundwater Zone 2.

PFOS: 0.0431 mg/kg

PFOA: 0.0026 mg/kg

PFHxS: 0.0303 mg/kg

PFHxA: 0.0271 mg/kg

Median concentrations detected from 10 celery samples:

PFOS: 0.0022 mg/kg

PFOA: Not detected

PFHxS: 0.0013 mg/kg

PFHxA: Not detected

The HHRA utilised plant uptake factors derived from the Fruit and Vegetable Uptake Study undertaken in 2017 at RAAF Williamtown to estimate PFAS concentrations in green vegetables.

However, this approach was considered to be conservative and likely overestimated the PFAS concentrations in green vegetables. Therefore, a sensitivity assessment has been undertaken using median PFAS concentrations reported in green vegetables in Groundwater Zone 2 (typical exposure). The sensitivity assessment is presented in Appendix K11.

HI estimated for adult residents (excluding drinking groundwater) based on median measured green vegetable concentrations decreased from 4.6 to 3.9.

HI estimated for child residents (excluding drinking groundwater) based on median measured green vegetable concentrations decreased from 13.2 to 11.8.

This indicates that the HHRA conclusions for the typical exposure scenario would not change where measured median green vegetable concentrations were used (i.e. based on the estimated HI, cumulative intakes would remain above the TDI).



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Adult exposure duration

Adult upper exposure duration: 29 years

Range: 1 year to 73 years based on responses to the Community Survey (average of 22 years)

Adult upper exposure duration: 73 years

The upper exposure duration adopted in the HHRA was based on the 95th percentile duration of residence in Australia from the 2001–2006 HILDA survey data (i.e. 35 years). It is assumed that the duration of residence starts at birth.

A sensitivity calculation was undertaken using the maximum exposure duration identified by adult residents in responses to the Community Survey.

The sensitivity assessment is presented in Appendix K12. As the sensitivity assessment is based on a maximum exposure duration, the assessment has been undertaken for Groundwater Zone 1 (upper exposure).

HI estimated for adult residents based on the maximum exposure duration (excluding drinking groundwater) remained unchanged.

This outcome is as expected given that PFAS are threshold compounds. For threshold compounds, the exposure duration and averaging time are equal and cancel each other out in the intake equation. Therefore, any adjustment the exposure duration (increasing or decreasing) would not affect the estimated HI.



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9.0 Managing Future PFAS Exposure As discussed in Section 3.4, while risk management is a separate process from risk assessment, the outcomes of the HHRA will be relevant to subsequent risk management decisions.

The HHRA outcomes have been used to identify which exposure pathways may contribute most significantly to overall PFAS exposure and therefore which aspects of the existing general precautionary advice from Queensland Health may be followed to most effectively minimise PFAS exposure in the future,





- Management Zone 3: the area identified as Groundwater Zone RoIA for the purpose of this HHRA Will be referred to as Management Zone 3.

These Management Areas and Zones are presented in Figure F8, Appendix A



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10.0 Conclusions The Stage 2C 2017 EI was designed to address data gaps identified at the completion of the 2016 Stage 2C EI studies and to provide an increased data set to evaluate the potential risks to human health from exposures to PFAS in the environment associated with current and ongoing use of the Site and the current land uses within the IA.

A total of 870 environmental samples and 168 biota samples have been collected for inclusion in this HHRA. These data have been used to refine the HHRA; specifically, the exposure assumptions, exposure point concentrations and risk characterisation. The additional data collected have also led to a refinement of understanding of the nature and extent of PFAS in the environment in the IA; in particular, the identification of Groundwater Zones which have been adopted for the characterisation of potential PFAS exposures to people in the IA. It is noted, however, that the extent of these Zones is current as of the 2017 Stage 2C EI, and may be subject to change following the collection of additional data and/or the result of groundwater movement over time.

Based on the data available at the time of preparation of this HHRA with respect to PFAS concentrations reported in environmental media, and with consideration of the uncertainties and limitations of the available data and information, the following conclusions are provided.

The HHRA assessed potential exposure that could occur as a result of current and ongoing activities at the Site and the current land uses and groundwater uses within the IA. This includes direct contact exposure to PFAS in soil, groundwater, surface water and sediment, and secondary exposure to PFAS accumulated in terrestrial biota and aquatic biota. The HHRA has also assessed future potential use of groundwater and surface water for aquaculture.

This HHRA has considered three groundwater PFAS detection zones off-Site within the IA, as depicted on Figure F3, Appendix A:

‘Groundwater Zone 2’ is represented by the upper 10% of the distribution of reported PFOS and PFHxS concentrations. The groundwater extraction bores are located immediately to the south and south-west of the Site, and have the highest magnitude of PFOS concentrations in the IA owing to their closer proximity to the Site, along with a potentially greater PFAS contribution from vertical migration of surface water in the vicinity of drainage channels 1 and 2. AECOM understands that some of the groundwater extraction bores in this Zone are used for commercial food production (livestock red meat production).

‘Groundwater Zone 1’ is represented by concentrations ranging between the upper 10% and 50% of the PFOS and PFHxS distributions in the IA. The groundwater bores are located further to the south and west of the Site, in areas where elevated PFAS concentrations in groundwater are inferred to have resulted from a combination of migration mechanisms including lateral groundwater migration and vertical migration from surface water.

‘Groundwater Zone RoIA’ is represented by concentrations ranging between the upper 50% and lower 10% of the PFOS and PFHxS distributions in the IA. The majority of the groundwater bores in this Zone have not reported detections of PFAS.

The groups of people who may be exposed to the PFAS detected in groundwater, and who were assessed in the HHRA, were:

residents within the IA surrounding the Site

recreational users of the land and waterways within the IA surrounding the Site

commercial (agricultural) workers at the properties within the IA surrounding the Site

on-Site personnel who work at the Site (considered to encompass all personnel who undertake training or other operational works at the Site facility, as well as infrequent visitors).

The key exposure pathways considered in the HHRA were:

consumption of groundwater used for domestic drinking water supply

incidental ingestion and dermal contact exposure associated with indoor domestic uses of groundwater (e.g. bathing/showering, household cleaning, laundry)



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incidental ingestion and dermal contact exposure associated with outdoor domestic uses of groundwater (e.g. swimming in pools, sprinkler play, irrigation, washing vehicles, washing animals)

consumption of home grown plant produce (e.g. fruit, vegetables) irrigated with groundwater or surface water, grown in soil historically irrigated with groundwater or historically inundated with floodwater

consumption of home grown animal produce (e.g. poultry eggs, red meat, milk) where animals drink groundwater or eat plants irrigated with groundwater or surface water, grown in soil historically irrigated with groundwater or historically inundated with floodwater

consumption of aquatic biota (fish and yabbies) from local waterways and from future potential aquaculture farms

incidental ingestion and dermal contact exposure associated with outdoor recreation at playing fields or local waterways (e.g. fishing, boating, swimming)

incidental ingestion and dermal contact exposure associated with commercial agriculture uses of groundwater (e.g. irrigation, washing vehicles, washing animals).

The EPC adopted in the HHRA for environmental media (groundwater, surface water, soil and sediment) were maximum concentrations because it was intended that the HHRA provide outcomes that could be applied to all people within each Groundwater Zone of the IA. Using the maximum concentration is likely to overestimate intakes for the average groundwater user in the IA. The EPC adopted in the HHRA for plant and animal produce consumed by humans were the median of detected PFAS concentrations (where sufficient data were available), as these were considered most representative of long term dietary intakes for frequent consumers of those produce. Maximum concentrations were adopted for the assessment of ingestion of livestock milk, red meat and eggs due to the limited number of samples available.

The HHRA conclusions are summarised in Table 62 for residents, Table 63 for commercial agriculture workers, Table 64 for recreational users of publicly accessible areas and Table 65 for on-Site personnel. The HHRA outcomes have been used to identify which aspects of the existing general advice from Queensland Health may be followed to most effectively minimise PFAS exposure in the future (https://www.qld.gov.au/environment/pollution/management/incidents/oakey). The suggested precautions on ways to minimise PFAS exposure are based on consideration of both the typical and upper range exposure scenarios, as follows:

Where both the typical and upper range exposure scenarios are associated with elevated PFAS intakes, it is suggested that the pathway be avoided.

Where only the upper range exposure scenario is associated with elevated PFAS intakes and the typical exposure scenario was identified to be associated with low and acceptable PFAS intake, it is suggested that the pathway be minimised, in order to avoid the upper range exposures assessed in this HHRA.





- Management Zone 3: the area identified as Groundwater Zone RoIA for the purpose of this HHRA Will be referred to as Management Zone 3.

These conclusions should be read in conjunction with the data gaps presented in Section 4.2.4 , the uncertainty evaluation in Section 8.1 and the sensitivity assessment presented in Section 8.3. It is



169

stressed that the risk assessment process involves a number of assumptions regarding Site conditions, human exposure and chemical toxicity. Further, there is unavoidable uncertainty that the algorithms used in the models provide a reliable approximation of reality. As such, conservative assumptions have been made in the selection of parameters for use in the HHRA based on available information. These assumptions will continue to evolve as additional data are collected that will provide verification or further refine the model input parameters.



170

Table 62 Summary of HHRA conclusions for residents

Exposure Pathway


Management Zone 1


Management Zone 2




Groundwater

Drinking groundwater or using it in cooking

Elevated Elevated Elevated Elevated Elevated Low & Acceptable

Management Zone 1 and Zone 2: Continue to follow Queensland Health advice to not drink groundwater or use it in cooking.

Management Zone 3: Because Queensland Health recommends that residents that live in or near a contaminated area reduce exposure to PFAS, and because the HHRA has estimated that residents’ PFAS exposure via drinking groundwater would be greater than for all other pathways combined, it is suggested that as a precautionary measure residents continue not to use groundwater for drinking or in cooking in Management Zone 3.

Incidental ingestion of groundwater as a result of indoor domestic use (excluding drinking water) and outdoor domestic use


Low & Acceptable

Low & Acceptable

Management Zone 1: Continue to follow Queensland Health advice to avoid the use of groundwater for: showering and bathing; filling swimming pools and children’s wading pools; and sprinkler play.

Management Zone 2: Continue to follow Queensland Health advice to minimise the use of groundwater for: showering and bathing; filling swimming pools and children’s wading pools; and sprinkler play.




171

Exposure Pathway


Management Zone 1


Management Zone 2




Dermal contact with groundwater as a result of indoor domestic use (excluding drinking water) and outdoor domestic use

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Soil


Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable



Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities or dust tracked back into the home

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable




172

Exposure Pathway


Management Zone 1


Management Zone 2





Consumption of vegetables that have been irrigated with water containing detectable PFAS, or have been grown in soil that has been irrigated or flooded with water containing detectable PFAS


Low & Acceptable

Low & Acceptable

Management Zone 1: Continue to follow Queensland Health advice to avoid consumption of home grown leafy green vegetables that have been irrigated with water containing detectable PFAS, or have been grown in soil that has been irrigated or flooded with water containing detectable PFAS.

Management Zone 2: Minimise consumption of home grown leafy green vegetables that have been irrigated with water containing detectable PFAS, or have been grown in soil that has been irrigated or flooded with water containing detectable PFAS.




173

Exposure Pathway


Management Zone 1


Management Zone 2






Low & Acceptable

Low & Acceptable





Elevated Elevated Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Management Zone 1: Continue to follow Queensland Health advice to avoid consumption of milk from home grown cattle or sheep that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS.

Management Zone 2 and Zone 3: No precaution suggested



174

Exposure Pathway


Management Zone 1


Management Zone 2




Consumption of eggs from backyard poultry that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS

Elevated Elevated Elevated Elevated Low & Acceptable

Low & Acceptable

Management Zone 1 and Zone 2: Continue to follow Queensland Health advice to avoid consumption of eggs from backyard poultry that have consumed water containing detectable PFAS, or have grazed in areas irrigated or flooded with water containing detectable PFAS.


Under circumstances where exposure of backyard poultry to media containing detectable PFAS can be prevented Scolexia (2017) estimated that a withholding period of 100 days after cessation of PFAS exposure to hens would likely be required for all four PFAS studied to reduce to less than the laboratory LOR in eggs from backyard poultry in the Management Area.



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Table 63 Summary of HHRA conclusions for commercial agriculture workers

Exposure Pathway


Management Zone 1


Management Zone 2




Groundwater

Incidental ingestion of groundwater as a result of outdoor commercial agriculture use

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Dermal contact with groundwater as a result of outdoor commercial agriculture use

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Soil


Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable



Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable

Low & Acceptable




176

Exposure Pathway


Management Zone 1


Management Zone 2







Low & Acceptable

Low & Acceptable









Low & Acceptable

Low & Acceptable




177

Table 64 Summary of HHRA conclusions for recreational users of publicly accessible areas

Exposure Pathway

Potential PFAS Exposures – Entire Management Area Suggested Precautions to Minimise Future PFAS Exposure

Upper Typical

Surface Water

Incidental ingestion of surface water as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Dermal contact with surface water as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Soil and Sediment

Incidental ingestion of soil and sediment as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Dermal contact with soil and sediment as a result of outdoor activities

Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities Low & Acceptable

Low & Acceptable



Consumption of fish from local waterways by recreational fishers

Elevated Low & Acceptable

Minimise consumption of fish from Oakey Creek.

Consumption of fish sourced from future aquaculture systems where groundwater or surface water containing detectable PFAS is used to supply the system

Elevated Elevated The potential risk to human health should be further evaluated based on Site-specific data prior to undertaking aquaculture in the Management Area using groundwater or surface water containing detectable PFAS in the future.



178

Table 65 Summary of HHRA conclusions for on-Site personnel

Exposure Pathway

Potential PFAS Exposures – On-Site Suggested Precautions to Minimise Future PFAS Exposure

Upper Typical

Soil


Low & Acceptable

Low & Acceptable



Low & Acceptable

Low & Acceptable


Inhalation of dust as a result of outdoor activities or dust tracked back into the workplace

Low & Acceptable

Low & Acceptable




179

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12.0 Limitations AECOM Australia Pty Ltd (AECOM) has prepared this report in accordance with the usual care and thoroughness of the consulting profession for the use of Department of Defence and only those third parties who have been authorised in writing by AECOM to rely on the report.

The report is based on generally accepted practices and standards at the time it was prepared. No other warranty, expressed or implied, is made as to the professional advice included in this report.

This report has been prepared by AECOM, an independent consultant engaged by Defence, based on information and sources described in the report. The findings and interpretations set out in the report are based on data gathered by AECOM within the time available, including publicly available information, data reports prepared for the Site and inspection of on-Site and off-Site areas.

The report is prepared in accordance with the scope of work and for the purpose outlined in the Proposal dated 17 November 2016.

This report should be read in full. No responsibility is accepted for use of any part of this report in any other context or for any other purpose or by third parties.

The methodology adopted and sources of information used by AECOM are outlined in the report.

Where this report indicates that information has been provided to AECOM by third parties, AECOM has made no independent verification of this information unless required as part of the agreed scope of work. AECOM assumes no liability for any inaccuracies in or omissions to that information.

This report was prepared between 27 January 2017 and 1 December 2017.The information in this report is considered to be accurate at the date of issue and is in accordance with conditions at the Site at the dates sampled. Opinions and recommendations presented herein apply to the Site existing at the time of our investigation and cannot necessarily apply to Site changes of which AECOM is not aware and has not had the opportunity to evaluate. This document and the information contained herein should only be regarded as validly representing the Site conditions at the time of the investigation unless otherwise explicitly stated in a preceding section of this report. AECOM disclaims responsibility for any changes that may have occurred after this time.

Except as required by law, no third party may use or rely on this report, unless otherwise agreed by AECOM in writing. Where such agreement is provided, AECOM will provide a letter of reliance to the agreed third party in the form required by AECOM.

To the extent permitted by law, AECOM expressly disclaims and excludes liability for any loss, damage, cost or expenses suffered by any third party relating to or resulting from the use of, or reliance on, any information contained in this report. AECOM does not admit that any action, liability or claim may exist or be available to any third party.

AECOM does not represent that this report is suitable for use by any third party.

Except as specifically stated in this section, AECOM does not authorise the use of this report by any third party.

It is the responsibility of third parties to independently make inquiries or seek advice in relation to their particular requirements and proposed use of the relevant property.

stage 2c environmental investigation - human … 2c environmental investigation - human health risk...

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