comprehensive investigation of per- and poly- fluoroalkyl … · 2020. 12. 9. · detailed site...

Comprehensive Investigation of Per- and Poly-

Fluoroalkyl Substances (PFAS) at RAAF Base Wagga

Department of Defence

Detailed Site Investigation

IA147400-003-N-RPT-005 | FINAL (Rev4)

16 August 2018

PFAS 2017-36-Wagga

Detailed Si te Inves tigati on

Department of D efence

Detailed Site Investigation – RAAF Base Wagga

IA147400-003-N-RPT-005 i

Comprehensive Investigation of Per- and Poly-Fluoroalkyl Substances (PFAS) at RAAF Base Wagga

Project No: IA147400

Document Title: Detailed Site Investigation

Document No.: IA147400-003-N-RPT-005

Revision: FINAL (Rev4)

Date: 16 August 2018

Client Name: Department of Defence

Client No: PFAS 2017-36-Wagga

Project Manager: DL

Author: DL, KM, SD, RE

File Name: J:\IE\Projects\04_Eastern\IA147400\21 Deliverables\DSI\Rev4\IA147400-003-N-RPT-

005-Rev4.docx

Jacobs Group (Australia) Pty Limited

ABN 37 001 024 095

Level 7, 177 Pacific Highway

North Sydney NSW 2060 Australia

PO Box 632 North Sydney

NSW 2059 Australia

T +61 2 9928 2100

F +61 2 9928 2500

www.jacobs.com

© Copyright 2018 Jacobs Group (Australia) Pty Limited. The concepts and information contained in this document are the property of Jacobs. Use

or copying of this document in whole or in part without the written permission of Jacobs constitutes an infringement of copyright.

Limitation: This document has been prepared on behalf of, and for the exclusive use of Jacobs’ client, and is subject to, and issued in accordance with, the

provisions of the contract between Jacobs and the client. Jacobs accepts no liability or responsibility whatsoever for, or in respect of, any use of, or reliance

upon, this document by any third party.

Document history and status

Revision Date Description By Review Approved

0 (DRAFT) 13 Mar 18 Draft for Defence and SA review DL RE DL

1 (DRAFT) 20 April 18 Draft for Project Control Group review DL RE DL

2 (DRAFT) 29 May 18 Final Draft for Defence and SA Review DL RE DL

3 (FINAL) 5 June 2018 Final for publishing DL RE DL

4 (FINAL) 16 August

2018

Final with Errata DL


IA147400-003-N-RPT-005 ii

Contents

Executive Summary ...................................................................................................................................... 1

Acronyms ...................................................................................................................................................... 7

1. Introduction ....................................................................................................................................... 9

1.1 Background ........................................................................................................................................ 9

1.1.1 Per- and Poly-Fluoralkyl Substances (PFAS) .................................................................................... 9

1.1.2 PFAS investigation and management program ............................................................................... 10

1.2 Scope of work ................................................................................................................................... 10

1.3 Relevant guidelines and standards .................................................................................................. 11

2. Site identification ............................................................................................................................ 12

2.1 Site details ........................................................................................................................................ 12

2.2 Site operations .................................................................................................................................. 13

2.2.1 RAAF Operations ............................................................................................................................. 13

2.2.2 Wagga to Tumbarumba rail line ....................................................................................................... 14

2.2.3 Wagga Wagga City Domestic Airport ............................................................................................... 14

2.3 Site infrastructure ............................................................................................................................. 14

2.3.1 Water supply ..................................................................................................................................... 14

2.3.1.1 Potable water .................................................................................................................................... 14

2.3.1.2 Irrigation water .................................................................................................................................. 15

2.3.2 Sewer 15

2.3.2.1 Base system ..................................................................................................................................... 15

2.3.3 Drainage ........................................................................................................................................... 16

2.4 Surrounding land use ....................................................................................................................... 16

2.4.1 General ............................................................................................................................................. 16

2.4.2 Former dairy farm ............................................................................................................................. 17

2.4.3 Plywood manufacturing mill .............................................................................................................. 17

2.4.4 NSW Rural Fire Service, Forest Hill ................................................................................................. 17

2.4.5 Murray Cod Hatchery ....................................................................................................................... 18

2.4.6 Forest Hill Sewage Treatment Plant ................................................................................................. 19

2.4.7 Suez Liquid Waste Storage and Transfer Station ............................................................................ 20

2.4.8 Former landfill ................................................................................................................................... 20

3. Site history ...................................................................................................................................... 22

3.1 Historical summary ........................................................................................................................... 22

3.2 Review of historical aerial photographs ............................................................................................ 22

4. Use of AFFF at the Base ................................................................................................................ 24

4.1 Current use of AFFF at the Base ..................................................................................................... 24

4.1.1 Base fire station ................................................................................................................................ 24

4.1.2 Fire Extinguisher Concrete Pad ....................................................................................................... 24

4.1.3 Remote training ................................................................................................................................ 25

4.1.4 Fire suppression or deluge systems ................................................................................................. 25

4.1.5 Portable fire equipment .................................................................................................................... 25


IA147400-003-N-RPT-005 iii

4.2 Historical use of AFFF at the Base ................................................................................................... 25

5. Environmental setting .................................................................................................................... 28

5.1 Topography and drainage ................................................................................................................ 28

5.2 Rainfall .............................................................................................................................................. 30

5.3 Prevailing winds ................................................................................................................................ 31

5.4 Geological setting ............................................................................................................................. 32

5.4.1 Alluvial and colluvial deposits ........................................................................................................... 33

5.4.2 Wantabadgery Granite and surrounding Sedimentary sequence .................................................... 34

5.5 Preliminary conceptual hydrogeological model ................................................................................ 34

5.5.1 Hydrostratigraphy and hydraulic properties...................................................................................... 34

5.5.1.1 Cowra and Lachlan Formations ....................................................................................................... 34

5.5.1.2 Wantabadgery Granite ..................................................................................................................... 36

5.5.2 Groundwater levels and flow regime ................................................................................................ 36

5.5.2.1 Cowra and Lachlan Formation ......................................................................................................... 37

5.5.2.2 Granite .............................................................................................................................................. 38

5.5.3 Groundwater quality ......................................................................................................................... 38

5.5.3.1 Cowra Formation .............................................................................................................................. 38

5.5.3.2 Lachlan Formation ............................................................................................................................ 38

5.6 Local groundwater users .................................................................................................................. 38

5.6.1 Water use survey .............................................................................................................................. 38

5.6.2 RAAF Base Wagga bores ................................................................................................................ 39

5.6.3 Riverina Water County Council water supplies ................................................................................ 40

5.6.4 Gumly Gumly Private Irrigation District ............................................................................................ 41

5.6.5 Murray Cod Hatchery ....................................................................................................................... 41

5.7 Groundwater dependent ecosystems ............................................................................................... 42

5.7.1 GDEs that are reliant on the surface expression of groundwater .................................................... 42

5.7.2 GDEs that are reliant on the sub-surface expression of groundwater ............................................. 42

5.8 Ecology ............................................................................................................................................. 43

6. Review of previous investigations ............................................................................................... 44

6.1 General ............................................................................................................................................. 44

6.2 CERAR (2004) .................................................................................................................................. 44

6.3 EarthTech (2005) .............................................................................................................................. 45

6.4 Maunsell (2006) ................................................................................................................................ 45

6.5 Vantage (2009) ................................................................................................................................. 46

6.6 Golder (2012a) ................................................................................................................................. 47

6.7 Golder (2012b) ................................................................................................................................. 48

6.8 GHD (2016) ...................................................................................................................................... 49

7. Previous PFAS sampling ............................................................................................................... 50

7.1 PFAS sampling conducted prior to commencement of the Project .................................................. 50

7.2 Sewage Treatment Plant sampling undertaken by the NSW EPA ................................................... 51

7.3 Jacobs preliminary sampling program .............................................................................................. 52


IA147400-003-N-RPT-005 iv

7.3.1 Sampling locations ........................................................................................................................... 53

7.3.2 Fieldwork methodology..................................................................................................................... 55

7.3.3 Quality assurance and quality control .............................................................................................. 55

7.3.4 Investigation criteria .......................................................................................................................... 55

7.3.5 Findings ............................................................................................................................................ 55

7.3.5.1 Drinking water supplies .................................................................................................................... 55

7.3.5.2 RAAF Base Irrigation ........................................................................................................................ 55

7.3.5.3 Murray Cod Hatchery ....................................................................................................................... 56

7.3.5.4 Surface water samples ..................................................................................................................... 56

8. Preliminary conceptual site model ............................................................................................... 57

8.1 Summary of key information ............................................................................................................. 57

8.2 Potential PFAS Sources ................................................................................................................... 58

8.2.1 On-Base ........................................................................................................................................... 58

8.2.2 Off-Base ........................................................................................................................................... 59

8.3 Transportation mechanisms ............................................................................................................. 60

8.4 Exposure pathways .......................................................................................................................... 60

8.5 Receptors ......................................................................................................................................... 61

9. Investigation data quality objectives ............................................................................................ 62

9.1.1 Step 1: State the problem ................................................................................................................. 62

9.1.2 Step 2: Identification of the decision or goal of the investigation ..................................................... 63

9.1.3 Step 3: Identify the information inputs .............................................................................................. 63

9.1.4 Step 4: Define the investigation boundaries ..................................................................................... 64

9.1.5 Step 5: Develop the analytical approach or decision rule ................................................................ 65

9.1.6 Step 6: Specify performance or acceptance limits ........................................................................... 65

9.1.7 Step 7: Develop the plan for obtaining data ..................................................................................... 66

10. Investigation approach and methodology ................................................................................... 67

10.1 Project Stages .................................................................................................................................. 67

10.2 Sampling plan ................................................................................................................................... 67

10.3 Analysis plan .................................................................................................................................... 68

10.4 Summary of investigation works completed ..................................................................................... 68

10.5 Fieldwork methodology and photos .................................................................................................. 69

10.6 Variations from the sampling and analysis plan ............................................................................... 70

10.6.1 Additional shallow soil sampling near the north west corner of the Base ........................................ 70

10.6.2 Additional groundwater investigations in Gumly Gumly and East Wagga ....................................... 70

10.6.3 Additional surface water and sediment sampling in the Murrumbidgee River ................................. 71

10.6.4 Shallow soil sampling at Equex ........................................................................................................ 71

10.7 Quality assurance and quality control .............................................................................................. 71

11. Investigation criteria ...................................................................................................................... 73

11.1 Investigation criteria for the protection of human health .................................................................. 73

11.1.1 Soil .............................................................................................................................................. 73

11.1.2 Groundwater and surface water ....................................................................................................... 74


IA147400-003-N-RPT-005 v

11.2 Investigation criteria for ecological protection .................................................................................. 75

11.2.1 Soil 75

11.2.2 Surface water ................................................................................................................................... 76

12. Investigation Results ..................................................................................................................... 77

12.1 Geology and Hydrogeology of the Base and Gumly Gumly Wetland .............................................. 77

12.1.1 Geology ............................................................................................................................................ 77

12.1.2 Perched groundwater ....................................................................................................................... 78

12.1.3 Hydrogeological Testing ................................................................................................................... 78

12.1.4 Water level monitoring ...................................................................................................................... 79

12.1.4.1 Regional groundwater ........................................................................................................... 79

12.1.4.2 Water level monitoring in new wells ...................................................................................... 80

12.1.4.3 Water level monitoring in the Murray Cod Hatchery Bores .................................................. 82

12.2 Groundwater quality – major ion analysis ........................................................................................ 83

12.2.1 Cation chloride ratio .......................................................................................................................... 83

12.2.2 Piper analysis ................................................................................................................................... 84

12.3 PFAS sampling and analysis results ................................................................................................ 86

12.3.1 On-Base primary source characterisation ........................................................................................ 87

12.3.1.1 Comparison of soil analysis results to adopted guideline values ......................................... 87

12.3.1.2 Comparison of perched groundwater results to human health guideline values .................. 89

12.3.2 On-Base irrigation areas................................................................................................................... 89

12.3.3 Off-Base source characterisation ..................................................................................................... 90

12.3.3.1 Investigation of Forest Hill STP, effluent irrigation and biosolids application areas ............. 90

12.3.3.2 Investigation of irrigation areas at Equex facility .................................................................. 92

12.3.4 Sampling of groundwater at the former Council landfill at Forest Hill .............................................. 92

12.3.5 Investigation of overland drainage pathways ................................................................................... 93

12.3.5.1 On-Base drainage ................................................................................................................. 93

12.3.5.2 Off-Base drainage ................................................................................................................. 97

12.3.6 Investigation of regional groundwater ............................................................................................ 103

12.3.6.1 Installed wells ...................................................................................................................... 103

12.3.6.2 Point of use sampling.......................................................................................................... 104

12.3.7 PFAS leachability ........................................................................................................................... 111

13. Refined Conceptual Site Model ................................................................................................... 112

13.1 Sources of PFAS contamination .................................................................................................... 112

13.2 Transport pathways ........................................................................................................................ 113

13.2.1 Surface water drainage .................................................................................................................. 113

13.2.2 Geology and Hydrogeology of the Base and Gumly Gumly Wetland ............................................ 113

13.2.3 Geology and Hydrogeology in the Northern Part of the Study Area .............................................. 114

13.2.4 Potential PFAS migration in groundwater ...................................................................................... 115

13.3 Potential receptors and risk screening results ............................................................................... 115

14. Data gaps and variability ............................................................................................................. 119

14.1 Additional data required for the Human Health and Ecological Risk Assessment ......................... 119


IA147400-003-N-RPT-005 vi

14.2 Potential variability .......................................................................................................................... 119

14.2.1 Surface water ................................................................................................................................. 119

14.2.2 Groundwater ................................................................................................................................... 120

15. Conclusions and Recommendations ......................................................................................... 121

16. References .................................................................................................................................... 123

Appendix A. Figures

A.1 Notes on the figures

Appendix B. Historical aerial images

Appendix C. EPBC Act Protected Matters Report

Appendix D. Threatened species, populations and ecological communities

Appendix E. Sampling and analysis plan

E.1 Sampling plan

E.1.1 New wells

E.2 Analysis plan

E.2.1 PFAS analysis

E.2.2 Leachability

E.2.3 Other soil and sediment parameters

E.2.4 Major ions

Appendix F. Fieldwork methodology

F.1 Sampling methodology

F.2 General field protocols

Appendix G. Photo log

Appendix H. Borelogs

Appendix I. Well development records

Appendix J. Groundwater sampling records

Appendix K. Surface water and sediment sampling records

Appendix L. Shallow soil sampling records

Appendix M. Vegetation sampling records

Appendix N. Hydrogeological testing

Appendix O. Quality assurance and quality control assessment

O.1 Quality assurance procedures

O.2 Quality control sampling and analysis

O.3 Data Validation

O.3.1 Quality assurance procedures

O.3.2 Quality control sampling and analysis

Appendix P. Data validation records

Appendix Q. Calibration records

Appendix R. 95% UCL calculation

Appendix S. Assessment of potential PFAS accumulation in soil at the Equex facility

Appendix T. Summary of laboratory results


IA147400-003-N-RPT-005 vii

Appendix U. Laboratory analysis reports

List of tables within body of report

Table 2.1 : Site Information Summary .................................................................................................................. 12 Table 2.2 : Base zones and precincts (AECOM, 2013) ........................................................................................ 13 Table 3.1 : Findings from the review of historical aerial images........................................................................... 22 Table 5.1 : RAAF Base Wagga irrigation bore details .......................................................................................... 40 Table 5.2 : RWCC East Wagga Borefield bore details ......................................................................................... 41 Table 5.3 : Murray Cod Hatchery bore details ...................................................................................................... 41 Table 7.1 : Previous investigations which have included PFAS analysis for the Base ........................................ 50 Table 7.2 : Results from NSW EPA sampling of treated effluent from Council STPs (µg/L) ............................... 52 Table 7.3 : Sampling locations for the Jacobs preliminary sampling program ..................................................... 53 Table 8.1 : Summary of potential on-Base sources of PFAS ............................................................................... 58 Table 8.2 : Summary of potential off-Base sources of PFAS ............................................................................... 59 Table 9.1 : Key aspects of the problem ................................................................................................................ 62 Table 9.2 : DSI decision statements ..................................................................................................................... 63 Table 9.3 : Information inputs ............................................................................................................................... 63 Table 9.4 : Investigation boundaries ..................................................................................................................... 64 Table 10.1 : Summary of samples by location and sample type .......................................................................... 69 Table 11.1 : Adopted guideline values for PFAS in soils for the protection of human health (mg/kg) (PFAS

NEMP, HEPA 2018) ............................................................................................................................................. 74 Table 11.2 : Adopted guideline values for groundwater and surface water for the protection of human health

(µg/L) (Department of Health, 2017)..................................................................................................................... 75 Table 11.3 : Adopted guideline values in soil for ecological protection (mg/kg) (PFAS NEMP, HEPA 2018) ..... 75 Table 11.4 : Investigation criteria for surface water ecological protection direct toxicity (µg/L) (PFAS NEMP,

HEPA 2018) .......................................................................................................................................................... 76 Table 12.1 : Hydraulic testing results summary ................................................................................................... 79 Table 12.2 : Summary of potential source area soil sampling results for PFOS, PFOS + PFHxS and PFOA

(mg/kg) .................................................................................................................................................................. 87 Table 12.3 : Summary of potential source area perched groundwater sampling results for PFOS + PFHxS (µg/L)

.............................................................................................................................................................................. 89 Table 12.4 : Summary of shallow soil sampling results for on-Base irrigation areas for PFOS + PFHxS (mg/kg)

.............................................................................................................................................................................. 90 Table 12.5 : Summary of analysis results for wastewater at the Forest Hill STP (µg/L) ...................................... 91 Table 12.6 : Summary of shallow soil sampling results for the Forest Hill STP and effluent irrigation areas

(mg/kg) .................................................................................................................................................................. 91 Table 12.7 : Summary of shallow soil sampling results at the Equex facility (mg/kg) .......................................... 92 Table 12.8 : Summary of the results for groundwater sampling at the former Forest Hill landfill (µg/L) .............. 93 Table 12.9 : Summary of shallow soil sampling results in north west corner of the Base (mg/kg) ...................... 94 Table 12.10 : Summary of shallow soil sampling results in drainage swale near fire extinguisher pad (mg/kg) . 94 Table 12.11 : Summary of shallow soil sampling results from drainage swales in the north western end of

Runway 12/30 (mg/kg) .......................................................................................................................................... 95 Table 12.12 : Summary of shallow soil sampling results from drainage swales near Taxiway C (mg/kg) ........... 95 Table 12.13 : Summary of shallow soil sampling results from drainage swales near Taxiways A and D (mg/kg)96 Table 12.14 : Summary of sediment sampling results from drainage channel in eastern part of Airport (mg/kg) 96 Table 12.15 : Summary of shallow soil sampling results from drainage channel in eastern part of Airport (mg/kg)

.............................................................................................................................................................................. 96 Table 12.16 : Summary of surface water sampling results at the Elizabeth Avenue stormwater discharge ....... 97 Table 12.17 : Summary of surface water sampling results from the Gumly Gumly Wetland (µg/L) .................... 98 Table 12.18 : Summary of sediment sampling results from the Gumly Gumly Wetland (mg/kg) ......................... 98 Table 12.19 : Summary of surface water sampling results from the drainage pathway to Gregadoo Creek (µg/L)

............................................................................................................................................................................ 100 Table 12.20 : Summary of sediment and soil sampling results from the drainage pathway to Gregadoo Creek

(mg/kg) ................................................................................................................................................................ 100 Table 12.21 : Summary of surface water sampling results for drainage via Marshalls Creek (µg/L) ................. 100 Table 12.22 : Summary of sediment and soil sampling results for drainage via Marshalls Creek (mg/kg) ....... 101


IA147400-003-N-RPT-005 viii

Table 12.23 : Summary of surface water sampling results for drainage via Kyeamba Creek (µg/L) ................. 102 Table 12.24 : Summary of sediment and soil sampling results for drainage via Kyeamba Creek (mg/kg) ........ 102 Table 12.25 : Summary of surface water sampling results for the Murrumbidgee River (µg/L) ......................... 103 Table 12.26 : Summary of sediment sampling results for the Murrumbidgee River (mg/kg) ............................. 103 Table 12.27 : Summary of PFAS sampling results for the newly installed wells (µg/L) ..................................... 103 Table 12.28 : Summary of groundwater sampling results for drinking water supply bores (µg/L) ..................... 105 Table 12.29 : Summary of soil and sediment sampling results for the Murray Cod Hatchery (mg/kg) .............. 106 Table 12.30 : Summary of surface water sampling results at the Murray Cod Hatchery (µg/L) ........................ 107 Table 12.31 : Summary of groundwater sampling results for the Murray Cod Hatchery (µg/L) ......................... 107 Table 12.32 : Summary of surface water sampling results for the property adjacent to the Murray Cod Hatchery

(µg/L) .................................................................................................................................................................. 109 Table 12.33 : Summary of soil and sediment sampling results for the property adjacent to the Murray Cod

Hatchery (mg/kg) ................................................................................................................................................ 109 Table 12.34 : Summary of off-Base groundwater bores not used for drinking water supply with PFAS

concentrations above LOR (µg/L) ....................................................................................................................... 109 Table 13.1 : Identified PFAS sources ................................................................................................................. 112 Table 13.2 : Summary of potential receptors, exposure mechanisms and risk screening results ..................... 115 Table A.1 : Symbols used to compare PFOS + PFHxS results to PFAS NEMP guideline values for human

health protection ................................................................................................................................................. 129 Table A.2 : Symbols used to compare PFOS results to PFAS NEMP guideline values for ecological protection

............................................................................................................................................................................ 130 Table E.1 : Sampling plan........................................................................................................................................1 Table E.2 : PFAS analytical suite (Defence, 2017b) ............................................................................................ 14 Table F.1 : Field sampling methodology ............................................................................................................... 17 Table F.2 : Summary of overarching field protocols ............................................................................................. 22 Table O.1 : Summary of acceptance criteria for quality assurance procedures................................................... 55 Table O.2 : Summary of acceptance criteria for quality control samples ............................................................. 56 Table O.3 : Summary of duplicate sampling rate by matrix .................................................................................. 58 Table O.4 : Frequency of trip blank collection ...................................................................................................... 58 Table O.5 : Summary of laboratory batches without trip blanks ........................................................................... 59 Table O.6 : Summary of duplicate RPD exceedances ......................................................................................... 60 Table O.7 : Summary of trip and rinsate blank detections ................................................................................... 68 Table O.8 : Summary of matrix spike non-conformances .................................................................................... 69 Table S.1 : Assumptions adopted for the assessment of PFAS accumulation in soil at the Equex facility ......... 76 Table S.2 : Calculations to determine period of time for soil concentrations to reach human health guideline

value ..................................................................................................................................................................... 77

List of figures within body of report

Figure 4.1 : Historical photo of the former Neptune aircraft fire training area (provided by the RAAF Base Wagga

Heritage Centre, not dated) .................................................................................................................................. 27 Figure 4.2 : Controlled burn of the Apprentice’s Club in 1985 (provided by the RAAF Base Wagga Heritage

Centre) .................................................................................................................................................................. 27 Figure 5.1 : Murrumbidgee River water levels at Wagga Wagga (2013 – 2017) (Office of Water, 2018) ........... 28 Figure 5.2 : Stream gauging data at Kyeamba Creek near Ladysmith (Office of Water, 2018) ........................... 29 Figure 5.3 : Mean monthly rainfall (mm) at Wagga Wagga AMO 1941 - 2017 .................................................... 30 Figure 5.4 : Daily rainfall and CRD 200 to 2017 ................................................................................................... 31 Figure 5.5 : Wind roses for 9am (left) and 3pm (right) observations at the BoM Wagga Wagga AMO station ... 32 Figure 5.6 : 1:100,00 geology map with approximate locations of the Base and Gumly Gumly Wetland (adapted

from Raymond, 1993) ........................................................................................................................................... 33 Figure 5.7 : Historical water level data (metres above sea level) from bore GW025383 (Office of Water data) . 36 Figure 12.1 : Regional groundwater hydrographs ................................................................................................ 81 Figure 12.2 : On- Base perched groundwater hydrographs ................................................................................. 81 Figure 12.3 : Murray Cod Hatchery groundwater well hydrographs ..................................................................... 82 Figure 12.4 : Molar ratio of Mg to Cl against Cl concentrations ........................................................................... 84 Figure 12.5 : Piper diagram of surface and groundwater sampled at RAAF Base Wagga .................................. 85


IA147400-003-N-RPT-005 ii

Figure 12.6 : PFOS + PFHxS concentrations from samples collected at surface and at depth in the Gumly

Gumly Wetland ..................................................................................................................................................... 99 Figure 12.7 : Sediment sampling results at the Murray Cod Hatchery ............................................................... 106 Figure 12.8 : Scatter plot of total and leachable PFOS + PFHxS concentrations in soil .................................... 111


IA147400-003-N-RPT-005 1

Report Errata

The following table outlines errata identified in Revision 3 of this report.

Section, Page No.,

Paragraph and Line

Original Text/Item Corrected Text/Item

Executive Summary. p. 5,

Conclusions and

Recommendations, c) iv

iv. Sampling of the well screened in the granite

to the east of the Base (MW233).

iv. Sampling of the well screened in the granite to the

east of the Base (MW223).

S2.3.3, p. 16, parra 3, line 1. The pit and pipe network discharges to the

Council network at a point in the north east area

of the Base.

The pit and pipe network discharges to the Council

network at a point in the north west area of the Base.

Figure 12.2, p.81 and p. 82 Plate for Figure 12.2 is repeated on pages 81

and 82.

Plate for Figure 12.2 should be present on page 80

only.

S12.3.5.1.1, p.93, parra. 1,

line 6

(location SW105) (location SW104)

Table 12.18, p98 Number of Samples column states ‘3’ Number of samples column should state ‘9’

Table 12.22, p. 101 Maximum concentration of PFOS + PFHxS

‘0.0357’

Maximum concentration 0f PFOS + PFHxS should

read ‘0.0410’.

Table 12.34, p.109 Sample date for MW232 reads 17/01/2018 and

the PFOS + PFHxS concentration for MW232

stated as 0.06 µg/L

This location was resampled on 21/2/18 due to quality

issue with sample on 17/1/18. The PFOS + PFHxS

concentration for MW232 was <0.01 µg/L. This row

has been deleted from the table.


PFOS + PFHxS concentration for MW233




concentration for MW233 was 0.18 µg/L


the PFOS + PFHxS concentration for MW234




concentration for MW234 was <0.01 µg/L. This row

was deleted from the table.

Table 12.34, p.109 Result above laboratory limits of reporting (but

below criteria) result from well OTH206/GW208

not listed in Table.

Inclusion of OTH206/GW208 PFOS + PFHxS

sampling results in Table 12.34, indicating no

exceedance of criteria.

Table 12.34, p.109 Concentration of PFOS + PFHxS above the

laboratory limits of reporting in OTH207/GW207

not listed.

Inclusion of OTH207/GW207 PFOS + PFHxS results

in Table 12.34.

S12.3.6.2.4, p.110, parra. 4,

5, 6

- New paragraphs added to discuss results in Table

12.34

S15, p122, parra 12,

recommendation c) iv

iv. Sampling of the well screened in the granite

to the east of the Base (MW233).

iv. Sampling of the well screened in the granite to the

east of the Base (MW223).

Figure 20 MW233 covered by scale indicator Amend scale indicator location to allow for visibility of

MW233.

Figure 22 GW207 not shown on figure. GW207 shown with symbol depicting exceedance of

drinking water criteria (0.07 µg/L).

Figure 22 OTH206/GW208 shown on Figure, but with

symbol depicting result of less than LOR.

OTH206/GW208 shown with symbol depicting result

above LOR, but below assessment criteria (drinking

water and irrigation).

Figure 25 BIO016 and BIO015 labels cover the shallow

soil labels.

Amend labelling to allow visibility of BIO016 and

BIO015.


IA147400-003-N-RPT-005 2

Executive Summary

The Department of Defence (Defence) commissioned Jacobs Group (Australia) Pty Ltd (Jacobs) to undertake a

Comprehensive Investigation of Per- and Polyfluoroalkyl Substances (PFAS) conditions at Royal Australian Air

Force (RAAF) Base Wagga (the Base) in New South Wales (NSW) (the Project). The investigation follows the

recommended general process for the assessment of site contamination outlined in Schedule A of the National

Environment Protection (Assessment of Site Contamination) Measure 1999 (NEPM) (NEPC 2013) and also

considers the guidance provided in the PFAS National Environmental Management Plan (PFAS NEMP) (HEPA,

2018).

The first stage of the Project involved desktop studies and preliminary environmental sampling to develop a

Preliminary Conceptual Site Model (CSM). The Preliminary CSM described potential PFAS sources, PFAS

transport pathways and the potential for human and environmental exposure. The model was then used to

develop a Sampling, Analysis and Quality Plan (SAQP) to guide a Detailed Site Investigation (DSI) involving

sampling and laboratory analysis of soil, surface water, sediment, groundwater and biota on the Base and in the

surrounding area. The DSI also included the collection of additional soil and water quality data as well as

hydrogeological testing to help characterise conditions in the area.

The DSI was completed between September 2017 and February 2018. This report presents the work completed

on the Project to date including the findings of the desktop study and preliminary sampling program, the

Preliminary CSM and SAQP, the DSI scope of works, investigation findings, conclusions and recommendations

for the next stages of the Project. These next stages of the project will include a Human Health and Ecological

Risk Assessment (HHERA) to further assess risks identified in the DSI and a PFAS Management Area Plan

(PMAP) which will set out actions for risks requiring management.

Background

Fire-fighting foam which contained PFAS as active ingredients was used at the Base from approximately 1970.

From 2004, Defence transitioned to a more environmentally safe product and also made changes to the way it

uses fire-fighting foam, including the construction of a purpose built fire extinguisher training facility at the Base.

PFAS are persistent chemicals that can bioaccumulate in humans and animals. Their high solubility and mobility

in surface water and groundwater can mean that PFAS can travel long distances. Consumption of water and

food grown using impacted water are thought to be the most important sources of human exposure to PFAS.

Sources of PFAS contamination

The DSI identified three key PFAS source areas on the Base – the former Fire Training Area in the east of the

Airport, the current Fire Station on the Base and the Fire Extinguisher Concrete Pad and Former Fire Station

area. Leachability testing of soil indicated the potential for significant discharge of PFAS to surface water and

groundwater from these areas.

Extent of PFAS contamination

Geology at the Base and in the surrounding area consists of alluvial deposits (clays, silts, sands and gravels) up

to approximately 60 metres thick underlain by granite with sedimentary outcrops. The alluvial deposits consist of

two formations; the Cowra Formation and the Lachlan Formation. The Cowra Formation is the upper part of the

alluvial deposits and consists primarily of silts and clays with some sand and gravel horizons. These horizons

vary in their thickness and lateral persistence. The underlying Lachlan Formation consists of sand and gravel

deposits with some clay and silt horizons. This formation is more permeable than the Cowra Formation and is

the main groundwater resource in the region.

The Cowra Formation on the Base was found to be dominated by dense high plasticity clays indicating that the

formation acts more like an impermeable confining layer over the Lachlan Formation. Therefore, the low

permeability nature of this horizon means it is not a significant pathway for vertical PFAS migration. PFAS


IA147400-003-N-RPT-005 3

concentrations in the Lachlan Formation within the Base were below the human health guideline values for

drinking water.

There are three surface water drainage pathways from the Base; drainage to the east to Kyeamba Creek,

drainage to the west to Gregadoo Creek and drainage to the north west to the Gumly Gumly wetland and on to

Marshalls Creek. Sampling of surface water, sediment and shallow soil along the Kyeamba Creek and

Gregadoo Creek drainage pathways has found that PFAS impacts are limited to farm dams and soil in close

proximity to the Base and these pathways do not appear to be significant PFAS transport pathways.

However, sampling of stormwater runoff from the Base to the Gumly Gumly wetland has identified significant

PFAS impacts in the drainage pathway to the wetland. The wetland then flows on to Marshalls Creek. This

pathway is considered a significant path for PFAS transport. Furthermore, drilling investigations conducted

during the DSI found the surficial clays of the Cowra Formation to be thinner in the wetland area than on Base

and water level monitoring at the Murray Cod Hatchery indicates that there is an enhanced vertical connection

between the Cowra and Lachlan Formations in this area.

Sampling of groundwater from the Cowra and Lachlan Formations at the Murray Cod Hatchery and at another

property adjoining the Gumly Gumly wetland has identified PFAS impacts exceeding the human health

guideline values for drinking water and, in the case of the hatchery, also exceeding the adopted the human

health guideline values for recreational water use.

Sampling of groundwater bores further downgradient of the wetland, including at the Riverina Water County

Council East Wagga Borefield bores, has found that PFAS concentrations are below the laboratory limits of

reporting. One exception is a sample from the Gumly Gumly Private Irrigation District (GGPID) bore which had

PFAS concentrations above the laboratory limit of reporting but below the human health guideline values for

drinking water. Samples collected from the GGPID bore on two other occasions had PFAS concentrations

below the laboratory limits of reporting.

Therefore, the extent of PFAS impacts identified above adopted guideline values outside the Base appears to

be limited to surface water and sediment along the Marshalls Creek drainage pathway and groundwater in the

Gumly Gumly wetland and surrounding properties. PFAS impacts were also identified at the Forest Hill Sewage

Treatment Plant and around the Forest Hill Council Landfill. However further investigation is required to better

understand the source and extent of these impacts.

Furthermore, PFAS concentrations above the drinking water guideline values were identified in a groundwater

sample from an existing well installed in the granite bedrock about 400 meters east of the Base. It is difficult to

conceptualise a pathway for PFAS migration from the Base to this well via groundwater. The well was installed

in 1956 and has not been used for many years. It is possible that the identified PFAS impacts were due to

migration of impacted water down the well construction from historical overland drainage. Further assessment of

potential flow paths to this well and resampling is recommended as part of the HHERA.

Potential risks to human health and the environment

Concentrations of PFAS in the samples collected were compared to investigation criteria. These criteria were

adopted from guideline values presented in the PFAS NEMP. Where concentrations exceed these criteria,

further assessment is required to understand whether there is an unacceptable risk to human health or the

environment.

Potential risks to human health and the environment that will require further assessment include:

PFAS impacts in the source areas do not present a human health risk to Base personnel. However, the

concentrations exceed the guideline values for ecological protection and risks to terrestrial ecology on

Base will require further assessment.

PFAS concentrations in surface water samples from farm dams in the Gumly Gumly wetland and from

drainage along the Marshalls Creek pathway exceeded the human health guideline values for recreational

water use and the guideline values for ecological protection. Risks to human health from dermal contact

(contact with skin) or incidental ingestion of the water will require further assessment. Potential risks


IA147400-003-N-RPT-005 4

associated with livestock and other animal exposure and uptake of PFAS from these surface water bodies

will also require assessment.

PFAS concentrations in Marshalls Creek indicate a potential for discharge of PFAS to the Murrumbidgee

River. Surface water samples from the river had PFAS concentrations below the laboratory limits of

reporting. However, bioaccumulation of PFAS in fish and other aquatic organisms can occur at

concentrations below these limits. Therefore, an assessment of potential risks to human health associated

with consumption of fish or shellfish from the Murrumbidgee River and risks to the environment will be

needed.

PFAS concentrations in farm dams close to the Base along the Gregadoo and Kyeamba Creek pathways

were below the guideline values for ecological protection (PFOS) and recreational water use

(PFHxS+PFOS). However, there is a risk for bioaccumulation in aquatic organisms (such as yabbies) that

could present a risk to human health or the environment. Therefore, further assessment of these risks will

be needed.

PFAS concentrations in the groundwater used to supply the aquaculture ponds at the Murray Cod Hatchery

as well as PFAS concentrations in surface water collected from the ponds indicate the potential for uptake

of PFAS in the hatchery produce. Further assessment of risks to human health and the environment at the

hatchery will be needed.

PFAS impacts were identified in effluent at the Forest Hill Sewage Treatment Plant and therefore risks to

workers at the plant as well as the risks associated with the use of treated effluent will need to be

assessed.

PFAS concentrations in groundwater bores used for drinking water supply were below the adopted

investigation criteria for drinking water. There is the potential for migration of PFAS from the Gumly Gumly

wetland in the future. Future risks to groundwater bores will require further assessment.

Conclusions and recommendations

The DSI identified three key source areas of PFAS contamination at the Base. This contamination is migrating

from the source areas in surface water runoff to the Gumly Gumly wetland and on to Marshalls Creek. PFAS in

the wetland is also migrating to groundwater in the Cowra and Lachlan Formations. The extent of contamination

in groundwater bores exceeding the human health guideline values for drinking water is limited to the Gumly

Gumly wetland and surrounding properties. While PFAS concentrations above the drinking water guideline

values were also identified in a well located approximately 400 meters east of the Base, this well is installed in

the granite formation and it is difficult to conceptualise a groundwater migration pathway from the Base to this

well. The well has not been used for many years and there are no other known users of groundwater in this

area.

The DSI has been completed in accordance with the NEPM and PFAS NEMP. The current extent of PFAS

contamination in terms of sources, pathways and receptors has been defined and therefore the objectives of the

DSI have been met. The data obtained from the DSI will be used to inform the next stages of the broader

investigation program that will further refine understanding of risk and the management actions that can be

implemented to control unacceptable risks. Recommendations for the next stages of the project can be

summarised as follows:

a) A Human Health and Ecological Risk Assessment (HHERA) will be undertaken to further assess risks

identified in this DSI. Targeted sampling will be required to obtain data to support the HHERA.

b) The HHERA will consider potential future risks to groundwater users downgradient of the Base. A

groundwater model is being developed to support this assessment. The groundwater model will assist in

refining the understanding of the extent of current PFAS impacts in groundwater, potential PFAS migration

pathways in groundwater or potential timeframes for PFAS migration. The model will also assist in

identifying targeted sampling locations for longer term monitoring.

c) In addition to the sampling required to support the HHERA, the following sampling is recommended to

address potential variability identified in the DSI:


IA147400-003-N-RPT-005 5

i. Sampling of the stormwater runoff from the area that includes the RFS station at Forest Hill during or

shortly after a rain event.

ii. Sampling of surface water in Marshalls Creek during or shortly following a rain event.

iii. Sampling of surface water and sediment in the Murrumbidgee River during the winter low flow period.

iv. Sampling of the well screened in the granite to the east of the Base (MW223).

d) A PFAS Management Area Plan will be developed as part of this Project and this will outline actions to

manage risks confirmed in the HHERA. This will include an Ongoing Monitoring Plan to monitor migration

of PFAS in the future. As noted in point b), the groundwater model will assist in identifying optimal locations

for the monitoring program and determining initial sampling frequencies based on potential variability.

e) Risks to workers involved in sub-surface construction or maintenance works will be highly dependent upon

the specific nature of the work and are outside the scope of this Project. However, the PFAS Management

Area Plan should include a requirement that a specific assessment of risks to these workers should be

undertaken prior to commencement of work in the identified PFAS source areas. This assessment should

also consider measures to ensure appropriate storage, handling and disposal of any PFAS impacted

materials.


IA147400-003-N-RPT-005 6

Important note about your report

The sole purpose of this report is to present the Detailed Site Investigation undertaken by Jacobs for the

Department of Defence (Defence) in connection with the Comprehensive Investigation of Per- and

Polyfluoroalkyl Substances (PFAS) at RAAF Base Wagga and surrounding areas.

This report was produced in accordance with and is limited to the scope of services set out in the agreement

between Jacobs and Defence. That scope of services, as described in this report, was developed with Defence.

All reports and conclusions that deal with sub-surface conditions are based on interpretation and judgement and

as a result have uncertainty attached to them. You should be aware that this report contains interpretations and

conclusions which are uncertain, due to the nature of the investigations. No study can investigate every risk,

and even a rigorous assessment and/or sampling programme may not detect all problem areas within a site.

This report is based on assumptions that the site conditions as revealed through sampling are indicative of

conditions throughout the site. The findings are the result of standard assessment techniques used in

accordance with normal practices and standards, and (to the best of our knowledge) they represent a

reasonable interpretation of the current conditions on the site.

The passage of time, the possibility of migration, the manifestation of latent conditions or impacts of future

events may require further examination of the project and subsequent data analysis, and re-evaluation of the

data, findings, observations and conclusions expressed in this report.

In preparing this report, Jacobs has relied upon, and presumed accurate, any information (or confirmation of the

absence thereof) provided by Defence and from other sources. Except as otherwise stated in the report, Jacobs

has not attempted to verify the accuracy or completeness of any such information. If the information is

subsequently determined to be false, inaccurate or incomplete then it is possible that our observations and

conclusions as expressed in this report may change.

Jacobs has prepared this report in accordance with the usual care and thoroughness of the consulting

profession, for the sole purpose described above and by reference to applicable standards, guidelines

procedures and practices at the date of issue of this report. For the reasons outlined above, however, no other

warranty or guarantee, whether expressed or implied, is made as to the data, observations and findings

expressed in this report, to the extent permitted by law. Opinions and judgements expressed in the report are

based on Jacobs’ understanding and interpretation of current regulatory standards and should not be construed

as legal opinions.

This report should be read in full and no excerpts are to be taken as representative of the findings. No

responsibility is accepted by Jacobs for use of any part of this report in any other context. This report has been

prepared on behalf of, and for the exclusive use of, Defence, and is subject to and issued in accordance with,

the provisions of the agreement between Jacobs and Defence. Jacobs accepts no liability or responsibility

whatsoever for, or in respect of, any use of, or reliance upon, this report by any third party.


IA147400-003-N-RPT-005 7

Acronyms

AFFF Aqueous Film Forming Foam

ARFF Aviation Rescue and Fire Fighting

ANZECC Australian and New Zealand Environment and Conservation Council

BOM Bureau of Meteorology

CRD Cumulative Rainfall Deviation

COPC Contaminants of Potential Concern

CSM Conceptual Site Model

CSR Contaminated Site Register

DEMS Defence Environmental Management System

DLWC NSW Department of Land & Water Conservation

DPI Department of Primary Industry

DSI Detailed Site Investigation

EC Electronic Conductivity

EMOS Estate Maintenance and Operation Support

EPA Environmental Protection Authority (NSW)

EPBC Environmental Protection and Biodiversity Conservation

GDE Groundwater Dependent Ecosystem

GGPID Gumly Gumly Private Irrigation District

HHERA Human Health and Ecological Risk Assessment

IBC Intermediate Bulk Container

LOR Limit of Reporting

mBGL Metres below ground level

MTG Motor Transport Group

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

NSW New South Wales

OMP Ongoing Monitoring Plan

PFAS Per- and Polyfluoroalkyl Substances

PFAS NEMP PFAS National Environmental Management Plan

PFCs Perfluorinated chemicals

PFOA Perfluorooctanoic acid

PFOS Perfluorooctane sulfonate

PFHxS Perfluorohexane sulfonate

PMAP PFAS Management Area Plan

POEO Protection of the Environment Operations Act,1997.

PP Priority Pollutants

PPL Defence Priority Pollutant List

RAAF Royal Australian Air Force

RFS Rural Fire Service

RTU Recruit Training Unit

RWCC Riverina Water County Council

SAQP Sampling and Quality Analysis Plan

STP Sewage Treatment Plant

WWCDA Wagga Wagga City Domestic Airport


IA147400-003-N-RPT-005 8

TDS Total Dissolved Solids

6:2FtS 6:2 fluorotelomer sulfonate

10:2FtS 10:2 fluorotelomer sulfonate


IA147400-003-N-RPT-005 9

1. Introduction

The Department of Defence (Defence) has commissioned Jacobs Group (Australia) Pty Ltd (Jacobs) to

undertake a Comprehensive Investigation of Per- and Polyfluoroalkyl Substances (PFAS) Site Conditions at

Royal Australian Air Force (RAAF) Base Wagga (the Base) in New South Wales (NSW) (the Project).

The key objectives of the Project are:

1) To characterise the extent of PFAS contamination on and surrounding RAAF Base Wagga

2) To identify the potential human and ecological receptors for the contamination

3) To assess the risks posed by the contamination to these potential receptors

4) To identify management actions to respond to the risks where necessary

The environmental investigations for the Project comply with the recommended general process for the

assessment of site contamination outlined in Schedule A of the National Environment Protection (Assessment

of Site Contamination) Measure 1999 (NEPM) (NEPC 2013) and also consider the guidance provided in the

PFAS National Environmental Management Plan (PFAS NEMP) (HEPA, 2018) – available at:

https://www.epa.vic.gov.au/PFAS_NMP).

A Preliminary Conceptual Site Model (CSM) for the Base and surrounding areas was prepared based on a

desktop review of existing information and a preliminary sampling program (Jacobs 2017a). The Preliminary

CSM was used to prepare a Sampling, Analysis and Quality Plan (SAQP) (Jacobs, 2017d) and this SAQP was

implemented in a Detailed Site Investigation (DSI).

The DSI is presented in this report. The report includes a summary of the Preliminary CSM, the objectives and

scope of the DSI, assessment criteria and findings.

Subsequent stages of the Project will involve a Human Health and Ecological Risk Assessment (HHERA) to

assess risks identified in this DSI and a PFAS Management Area Plan (PMAP) which will set out actions for

risks requiring management.

Defence has appointed a Site Auditor, Peter Lavelle from Environmental Resources Management (ERM), to

provide an independent peer review of Jacobs’ technical deliverables. Peter Lavelle is accredited by the NSW

Environmental Protection Authority (EPA) as a Site Auditor under the NSW Contaminated Land Management

Act 1997.

Defence has also convened a Project Control Group consisting of NSW Government agencies, the City of

Wagga Wagga Council and Riverina Water County Council to obtain input from these stakeholders through the

project.

1.1 Background

1.1.1 Per- and Poly-Fluoralkyl Substances (PFAS)

PFAS are a class of manufactured chemicals that have been used since the 1950s to make products that resist

heat, stains, grease and water. PFAS have been used across Australia and internationally in a range of

common household products and specialty applications, including in the manufacture of non-stick cookware;

fabric, furniture and carpet stain protection applications; food packaging and in some industrial processes.

Defence and other organisations have used Aqueous Film Forming Foam (AFFF) products to suppress liquid

fuel fires, in firefighting training operations and in fixed deluge systems for bulk fuel or chemical storage and

aircraft hangars throughout Australia. From approximately 1970, Defence used an AFFF product called

Lightwater, produced by 3M using an electrochemical fluorination process. This product contained PFAS

including perfluorooctane sulfonate (PFOS); perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate

(PFHxS). From 2004, Defence transitioned to a product called Ansulite, an AFFF product that is produced


IA147400-003-N-RPT-005 10

through a telomerisation process. Ansulite contains fluorotelomers such as 6:2 fluorotelomer sulfonate (6:2FtS)

and 10:2 fluorotelomer sulfonate (10:2FtS) which are considered PFAS precursors.

Defence has also made changes to the way it uses AFFF to ensure that the risk of releasing AFFF into the

environment is minimised.

Due to the widespread use of PFAS-containing products, and because these chemicals persist in humans and

the environment, most people living in developed countries will have some level of PFOS, PFOA and PFHxS in

their body. As a result, the Environmental Health Standing Committee (enHealth)1, recommends that human

exposure to these chemicals is minimised as a precaution (enHealth, 2016).

1.1.2 PFAS investigation and management program

In order to assess potential impacts associated with the historic use of AFFF, Defence has commenced a

national program to review its estate and investigate and implement a comprehensive approach to manage the

impacts of PFAS on, and in the vicinity of, some of its bases around Australia.

Defence completed a risk ranking of facilities based on their potential for PFAS impacts to be present. RAAF

Base Wagga was identified as a facility that required investigation of PFAS based on:

Historical AFFF use and fire training activities being undertaken

Use of groundwater in the area surrounding the Base

Potential sensitive receptors in the surrounding area, including surface water systems and farming

activities

The comprehensive investigation at RAAF Base Wagga commenced in May, 2017.

1.2 Scope of work

The scope of work performed by Jacobs and covered in this DSI is summarised as follows:

Review of information provided by Defence and government agencies as well as publicly available

information to identify relevant site characteristics, potential PFAS sources, potential receptors to

contamination and potential pathways of contaminant transport

Survey of the community surrounding the Base to understand use of surface water and groundwater

Observations on the Base and through a general reconnaissance of the area to ground truth current land

use and the environmental setting

Development of a preliminary CSM to identify potential source, pathway receptor linkages for PFAS

contamination at the Base and surrounding area

Identification of data gaps and the preparation of a SAQP for a DSI to fill these gaps

Implementation of the SAQP including sampling of soil, sediment, surface water, groundwater and biota

Screening of the analytical data against nationally accepted assessment criteria in order to identify

potential unacceptable risks that may need to be further evaluated

Refinement of the CSM based on the data obtained during the DSI

Preparation of this DSI report

Further details of the work performed are provided in later sections of this report.

1 enHealth is a standing committee of the Australian Health Protection Principal Committee (AHPPC). It’s membership consists of Commonwealth,

State and Territory health departments, New Zealand Ministry of Health, and National Health and Medical Research Council.


IA147400-003-N-RPT-005 11

1.3 Relevant guidelines and standards

The DSI has been undertaken in accordance with or in consideration of the following guidelines and standards:

a) National Environment Protection (Assessment of Site Contamination) Measure 1999 (NEPM) (NEPC,

2013).

b) PFAS National Environmental Management Plan (PFAS NEMP) (HEPA, 2018)

c) Commonwealth Environmental Management Guidance on Perfluorooctane Sulfonic Acid (PFOS) and

Perfluorooctanoic Acid (PFOA) (Department of Environment and Energy, 2017)

d) Final Health Based Guidance Values for PFAS For Use in Site Investigations In Australia (Department of

Health, 2017)

e) Perfluorinated Chemicals in Food (FSANZ, 2017)

f) Designing Sampling Programs for Sites Potentially Contaminated by PFAS, Guidance Document (NSW

EPA, November 2016)

g) Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances

(PFAS), Contaminated Sites Guidelines (WA DER, 2017)

h) Guidelines for Consultants Reporting on Contaminated Sites (OEH, 2011)

i) AS 4439.1–1999. Wastes, Sediments and Contaminated Soils – Preparation of Leachates, Preliminary

Assessment

j) AS 4439.3–1997. Wastes, Sediments and Contaminated Soils – Preparation of Leachates, Bottle Leaching

Procedure

k) AS4482.1 – 2005. Guide to the investigation and sampling of sites with potentially contaminated soil, Part

1: Non-volatile and semi-volatile compounds

l) AS/NZS 5667.11:1998. Water quality - Sampling - Guidance on sampling of groundwaters

m) Minimum construction requirements for water bores in Australia (National Uniform Drillers Licensing

Committee, 2013)

n) Guidelines for the NSW Site Auditor Scheme (3rd Edition) (NSW EPA, 2017)

o) Guidelines for the Assessment and Management of Groundwater Contamination (NSW DEC, 2007)


IA147400-003-N-RPT-005 12

2. Site identification

Except where noted, the following information on the Base and surrounding area has been sourced from Golder

Associates (Golder) Stage 1 Environmental Investigation (Golder, 2012a) and Connell Wagner, Requirements

Analysis, RAAF Base Wagga (Connell Wagner, 2008), which document a comprehensive review of the Base

and associated facilities.

2.1 Site details

RAAF Base Wagga is located at Forest Hill in NSW. Forest Hill is a suburb of Wagga Wagga and is located

approximately 10 km east of the central business district.

The Base location is shown in Figure 1 and the Base layout is provided in Figure 2. A summary of site

information is presented in Table 2.1.

Table 2.1 : Site Information Summary

Aspect Site specific information

Defence Property ID 0906

Street Address Sturt Highway

Locality Forest Hill, NSW, 2651

Municipality City of Wagga Wagga

State NSW

Site Area 310 Hectares (3.1 square kilometres)

Legal Description Lots 1, 2, 3 and 4 in DP 1113351

Lot 2 in DP 848579

Lots 62 and 141 in DP 757232

Lots 1 and 2 in DP 85382

Lot 1 in DP 436207

Lots 1 and 2 in DP 819642

Lot 1 in DP 190467.

Zoning SP2 Infrastructure according to the Wagga Wagga Local Environmental Plan

2010.

Ownership details The Base, with the exception of part of Lot 2 in DP 819642 is owned by the

Commonwealth. Lot 2 in DP 819642 is the disused Tumbarumba branch rail

line reserve. The reserve runs east – west across the Base immediately

north of the Hanger Precinct. This lot is owned by the NSW Government

(RailCorp) and leased by Defence. Details of the lease between RailCorp

and Defence were not available.

The Base contains an operational airfield, Wagga Wagga City Domestic

Airport (WWCDA) which is operated by the City of Wagga Wagga Council

(Council) via a 30 year lease agreement (1 July 1995 to 30 July 2025)

established between Defence and Council.


IA147400-003-N-RPT-005 13

2.2 Site operations

The Base includes numerous buildings and facilities which are divided in to several precincts. These include:

The Hanger Precinct, which includes numerous aircraft hangers and several workshops which are currently

or have historically been used for the maintenance of aircraft or the training of mechanical and engineering

trades;

The Training and Residential precincts, which includes numerous classroom training facilities, several

recreational buildings and facilities, messing facilities and numerous residential buildings; and

WWCDA which includes the domestic airport terminal, several privately owned hangers including the

Regional Express hangers, the air traffic control tower and the WWCDA ground crew depot.

The key areas of the Base are shown in Figure 2 and are discussed further below.

2.2.1 RAAF Operations

The RAAF operations at the Base cover an area of approximately 116 hectares. Access to the RAAF operations

is provided from Newton Road, which connects to the Sturt Highway.

The RAAF operations primarily include training facilities such as trades, class room and outdoor training

facilities, residential properties, administration, recreation and support services (such as messes and

firefighting). Facilities include aircraft hangers (used for aircraft maintenance and trade training), warehousing

and refuelling facilities.

The RAAF operations area also includes recreational playing fields and a former golf course (no longer in use).

As noted above, the RAAF operations include firefighting services. These services are provided for the Base

including aviation rescue and fire fighting services for the airport. The fire fighting services are operated by a

Defence contractor, Broadspectrum. There is a fire station located at Barker Street on the Base. The station

includes two fire response vehicles. AFFF storage and use connected with RAAF operations is discussed in

Section 4.

Defence acquired an adjoining farm, Yarunga, located in the south east of the Base. The farm includes a small

farm house, former shearing shed (with yards), former sheep dip, and former hay shed. The farm is currently

used by Defence for land–based Defence training.

The RAAF Base Wagga Zone Plan (AECOM, 2013) defines various zones across the Base. The zones and

precincts within these zones are summarised in Table 2.2. The zones are also presented on Figure 2.

Table 2.2 : Base zones and precincts (AECOM, 2013)

Zone Precincts

Operational Zone Aircraft aprons

Operational support zone Operational support zone

1 Recruit Training Unit

Open training zone Training areas

Base support zone Heritage

Policing

Recreation

Base services

Parade ground

Future Multi-purpose (former golf source area)

Base community facilities

Base entry


IA147400-003-N-RPT-005 14

Zone Precincts

Domestic zone Officer’s Living-in Accommodation and co-located messing

Airmen’s Living-In Accommodation and co-located messing

Open space zone Open space and vacant land

It is noted that Base Management has confirmed to Jacobs that no children live on the Base and children are

not present for extended periods on the Base.

2.2.2 Wagga to Tumbarumba rail line

The rail infrastructure associated with the disused Wagga to Tumbarumba rail line reserve that bisects the Base

appears to have been removed. The land that comprised the rail reserve within the Base covers an area of

approximately 9 hectares and is now vegetated land with some paved areas for road and foot path crossings.

2.2.3 Wagga Wagga City Domestic Airport

WWCDA is located in the central and southern portion of the Base, and covers an area of approximately 194

hectares. The WWCDA includes terminal buildings, the Air Traffic Control Tower, aircraft hangers, aircraft

refuelling infrastructure, administration, training and support facilities. The airport has two runways, one tarmac

and one grass as well as paved taxiways and aircraft parking areas.

Defence leases the land to Council over a 30-year term for use as a commercial airport (the lease commenced

in 1995 and expires in 2025). Council is responsible for the maintenance and upkeep of this infrastructure,

including the runways, taxiways, airfield lighting and air traffic control services.

Under the Wagga Wagga Airport Lease, Defence is allowed to undertake up to 60 operations a year involving

Hercules C130 Aircraft and is entitled to the use of and access to the aerodrome and the land for these aircraft.

Defence is also entitled to carry out operations involving its aircraft at the aerodrome at unrestricted frequency

where the requirements for an operation of such aircraft do not exceed the strength of the pavement. Under the

lease agreement, Defence has unrestricted access to the explosive ordnance (EO) storage area, the helicopter

training area and open training area (Connell Wagner, 2008). These areas are shown on Figure 2.

There are two bulk fuel facilities at the airport, a BP facility and a Mobil facility (operated by World Fuel

Services). The BP Facility consists of two underground storage tanks and bowsers (Golder, 2012a). In a

telephone conversation with Jacobs on 7 August 2017, a representative from BP advised Jacobs that the there

are no AFFF installations at the BP facility and, given the facility consists of underground tanks, historical AFFF

installations would be highly unlikely.

The Mobil facility consists of three 55 kL above ground storage tanks within a concrete bund (Golder, 2012a). In

a telephone conversation with Jacobs on 7 August 2017, a representative from World Fuel Services advised

Jacobs that there are no AFFF installations at the Mobil facility. The representative advised Jacobs that a 200

Litre (L) drum of protein based fire fighting foam was historically present at the facility. However, this was

donated to the Forest Hill Rural Fire Service (RFS) some time between 2008 and 2010. The World Fuel

Services representative was not aware of any fire incidents or fire training that had occurred in or around the

Mobil facility.

2.3 Site infrastructure

2.3.1 Water supply

Information on the Base water supply was obtained from Cardno (2016a) and is summarised below.

2.3.1.1 Potable water

The current potable water service to the Base consists of a series of interconnected ring main loops supplied

from the Riverina Water County Council (RWCC) via a main located along Sturt Highway. A separate RWCC


IA147400-003-N-RPT-005 15

connection from Elizabeth Avenue supplies the Council leased airport area. There is also a separate RWCC

connection off Brunskill Road supplying water to the 1 Recruit Training Unit (RTU) Training Facility and the

mask testing workshop located in the south east corner of the airfield.

The majority of the water services were constructed as part of the original Base development in the 1940s and

the original water supply was also from the local water authority (Southern Riverina County Council). However

in 1963, Defence installed two off-site groundwater bores (Bore 1 and Bore 2) and in 1966 an elevated concrete

tank in order to provide water supply to the Base. A third off-site bore (Bore 3) was installed in 1967 as a result

of capacity problems with the existing bores and the Base was also connected to the RWCC main at Braehour

Street.

Bore 2 collapsed in 1973 and was replaced by Bore 4 in the same location. Bore 5 (also off-Base) was installed

in 1976. RWCC upgraded the supply main in 2004 to provide a back-up potable water supply to the Base’s bore

water. Potable water supply was switched permanently to RWCC supply in 2007 following a well collapse.

Base personnel confirmed to Jacobs that the RWCC water supply is also used for the Base swimming pool.

The off-Base bores are discussed further in Section 5.6.2. The sources of water for the RWCC supplies are

discussed in Section 5.6.3.

2.3.1.2 Irrigation water

A number of the vegetated areas of the Base are irrigated with manual and automatic sprinklers or hoses. Most

of the general grassed areas between buildings are irrigated with potable water (RWCC supply). The former golf

course and recreational fields are irrigated with water supplied from the off-site Bore 5 discussed in Section

2.3.1.1. Bores 1 and 2 have silted up and are no longer serviceable. Bore 3 is believed to be operational or

could be recommissioned but is not currently in use.

The Estate Maintenance and Operation Support (EMOS) contractor for the Base advised Jacobs in an email

dated 28 June 2017 that prior to the potable water supply being switched permanently to RWCC supply in 2007,

bore water was used to service all Base irrigation areas.

The areas irrigated with bore water were noted as potential secondary PFAS sources in the Preliminary CSM for

the Project and are discussed further in Section 8.1 and are identified on Figure 6b.

2.3.2 Sewer

2.3.2.1 Base system

Information on the Base sewer system was obtained from Cardno (2016b) and is summarised below.

The Base sewer system was originally constructed as part of its development in 1944 and approximately 85% of

that network is still used today. The system is predominantly a gravity network, but there are two small pumping

stations and a common rising main within the Council leased airport area. Sewage from the airport area flows

into the Base network. The Base network then discharges to a gravity mains at the north-west corner of the

Base which conveys the sewage to the Forest Hill Sewage Treatment Plant (STP) located approximately 1.8km

north of the Base on Braehour Road, Forest Hill (see Section 2.4.6).

The Southern Training Areas on the Base include a training facility (B772) and amenities building (B774) which

are serviced by a local septic or absorption system. There is also a farmhouse in the south east corner of the

Base, near the corner of Brunskill Road and Oheirs Road which is assumed to be serviced by a local septic

system.

There are a number of grease traps installed at the Base for treatment of wastewater from kitchen and mess

facilities prior to discharge to the sewer under a Trade Waste agreement with Council. There are also a number

of oil water separators which intercept stormwater and discharge to the stormwater network. These include an


IA147400-003-N-RPT-005 16

oil water separator in the fire station wash bay (Building 90, asset number SGT0006) and an oil water separator

for the current fire training area (Building 74, asset number SGT007).

The discharge method for the oil water separator in the fire station wash bay is not clear in the Cardno (2016b)

report. The oil water separator for the current fire training area consists of two in ground concrete tanks. Cardno

(2016b) indicates that there are no stormwater connections to these tanks. However, Aurecon (2009) states that

when these tanks are full, additional wastewater overflows to the stormwater network (see Section 4).

Prior to the construction of the additional treatment plant at the Forest Hill STP, there was a STP on Base. It is

understood the former STP was located near the north western corner of the Base and consisted of a primary

screening facility and two secondary treatment circular trickling filter tanks, located on the western boundary in

the vicinity of the current residential precinct.

Information provided to Jacobs by the Base EMOS contractor in an email dated 20 July 2017 indicated that the

on Base STP previously discharged to ponds located in the current location of the Forest Hill STP. These ponds

were operated by Defence. After treatment in these ponds, the treated effluent was discharged to Kyeamba

Creek near the confluence with Murrumbidgee River.

2.3.3 Drainage

Information on the Base stormwater system was obtained from Cardno (2016c) and is summarised below.

The stormwater network for the RAAF operations areas of the Base north of the airfield consists of a pit and

pipe network throughout the majority of this area. There are also open grass-lined swales that run east to west

along the former rail corridor. These swales drain into the pit and pipe network. An open grass-lined swale also

runs parallel to Edwards Street and along the northern and western boundaries of No 1 Recruit Training Unit

and the pervious areas south of Edwards Street. Cardno (2016c) indicates that this swale discharges overland.

However, it seems more likely that drainage from the swale would eventually discharge into the Base pit and

pipe system.

The pit and pipe network discharges to the Council network at a point in the north west area of the Base. This

part of the Council network collects stormwater from the Base as well as stormwater from part of Forest Hill and

discharges the water to Gumly Gumly Wetland.

An area of the north east of the Base discharges to off-Base farm dams via overland flow. During extended

periods of high rainfall, water would flow from these dams to Kyeamba Creek.

Information in relation to drainage at the WWCDA areas is provided in GHD (2004). There is a pit and pipe

network in the paved areas of the WWCDA lease area around the airport buildings and apron areas. This pit

and pipe network connects to the pipe network for the RAAF operations area and so stormwater from this area

of the airport also eventually discharges through the north west of the Base. There is an open drain in the north

east area of the airfield on the southern side of the main runway which collects stormwater runoff from this area

and discharges to a farm dam on the adjoining property (former dairy farm). The southern area of the airfield

drains to an open unlined swale which drains water towards the west into a farm dam located at the south

western corner of the Base. A small area in the western portion of the airfield drains to the road drainage along

Elizabeth Avenue and then into a farm dam on the property on the western side of the road.

Drainage flows from the Base are presented in Figures 3a and 3b. Regional drainage is discussed further in

Section 5.1.

2.4 Surrounding land use

2.4.1 General

According to the Wagga Wagga Local Environmental Plan 2010, the land surrounding RAAF Base Wagga is

primarily zoned RU1 Primary Production with the exception of the Forest Hill community which includes the


IA147400-003-N-RPT-005 17

residential area to the north west of the Base as well as the small residential area immediately east of the Base.

These areas are both zoned R1 General Residential and generally comprise single dwelling lots.

The Forest Hill Shopping Centre is located on the corner of Sturt Highway and Fife Street and includes a

grocery store and post office. The Forest Hill Primary School is located to the north of the Base, on the northern

side of the Sturt Highway, and Forest Hill Caravan Park is located east of the Base on the Sturt Highway.

Apart from the general residential area of Forest Hill and small residential area immediately east of the Base,

the land surrounding the Base is dominated by agricultural land uses. Agricultural land in the region is

predominantly used for beef and sheep grazing as well as cereal crops.

A summary of surrounding land use (within 200 metres (m) of the site) of the Base includes:

North: Sturt Highway, Forest Hill Primary School followed by agricultural land

East: Residential buildings, the Forest Hill Caravan Park and agricultural land including a former dairy farm.

South: Agricultural land.

West: Residential area, Council recreational playing fields and public open space, Elizabeth Avenue and

agricultural land.

Key areas of interest in the region surrounding the site are discussed in the following sections and are

presented on Figure 1.

2.4.2 Former dairy farm

A property to the east of the Base was used as a dairy farm until approximately September, 2017. Jacobs

understands the farm will be used for beef livestock grazing in the future.

There is one groundwater bore on the property. However, the operator stated to Jacobs that the bore has not

been used in many years and there is no power to the pump. The dairy cows were watered from the farm dams

and from water supplied by RWCC. The operator stated to Jacobs that the beef livestock would also be watered

from the farm dams and RWCC water supply.

One of the farm dams on the property receives stormwater runoff from the Base. The farm operator advised

Jacobs that maintenance excavation of sediment was performed on this dam in 2016 and the excavated

sediment was placed on land near the dam. Other farm dams on the property do not receive stormwater runoff

from the Base, these are fed from overland runoff from south of the property.

2.4.3 Plywood manufacturing mill

There is an area zoned IN1 General Industrial located west of the Base, on the northern side of the rail corridor.

This land is currently occupied by the Ausply Plywood Manufacturing Mill owned by Big River Group Pty Ltd. Big

River Group Pty Ltd holds an Environment Protection License (License number 1046) issued by the NSW EPA

under the Protection of the Environment Operations Act (POEO) 1997.

There is a registered groundwater bore at this property (GW025641). The bore is listed for commercial or

industrial purposes and is 50.9 m deep. Big River Group Pty Ltd advised Jacobs that there are no personnel

that are aware of the presence of the bore and all water for the property is sourced from RWCC.

2.4.4 NSW Rural Fire Service, Forest Hill

The NSW Rural Fire Service (RFS) has a fire station located at Elizabeth Avenue in Forest Hill. In an email to

Jacobs dated 28 June 2017, the NSW RFS stated that:

1) The RFS station at Elizabeth Avenue in Forest Hill was constructed in the 1990’s and there was previously

no station in the area.


IA147400-003-N-RPT-005 18

2) Niagara Class B Concentrate 1-3% and Forexpan Class A Concentrate are currently used for foam

products by the RFS. 3M AFFF 6% was previously used. Purchase of this product ceased in 2005 and

remaining stock was quarantined in 2007.

3) The RFS has no knowledge of fire training activities involving the use of AFFF at Forest Hill or in the

surrounding areas. The RFS stated that AFFF is an expensive product and therefore bush fire foam would

typically be used for training scenarios as a cheaper alternative.

4) The RFS does not maintain records regarding incidents that the RFS responded to and applied AFFF.

5) The RFS has not undertaken any PFAS investigations at Forest Hill other than to identify quarantined

stocks and remove for destruction.

The station is noted as a potential source of PFAS contamination in Section 8.2.

A map of the Council stormwater network supplied by Council to Jacobs on 26 July 2017 indicates that

stormwater drainage from the RFS property flows via the Council stormwater network north along Elizabeth

Avenue and discharges to the canal that flows into Gumly Gumly Wetland. The discharge point to the canal is

next to the discharge point where stormwater from the Base discharges.

2.4.5 Murray Cod Hatchery

The Murray Cod Hatchery is a private operation located, approximately 2km north west of the Base. The

hatchery consists of a series of ponds that are used (or previously have been used) for aquaculture. Jacobs

discussions with the hatchery operator on 20 June 2017, 7 July 2017 and 30 October 2017 identified the

following:

The hatchery primarily produces fingerlings for stocking of farm dams and aquariums. However full size

fish were previously occasionally grown for sale and consumption by the hatchery operator.

The hatchery has historically produced Murray Cod (Maccullochella peelii), Silver Perch (Bidyanus

bidyanus), Golden Perch (Macquaria ambigua), Catfish (Tandanus tandanus) and Yabbies (Cherax

destructor).

Potable water for the buildings is supplied by RWCC. However, the hatchery operator stated to Jacobs that

groundwater was previously used for non-potable domestic use.

There are six groundwater bores within the hatchery. Groundwater is used as the primary water source for

the fish production ponds. Surface water from the areas of Gumly Gumly Wetland surrounding the hatchery

is occasionally pumped into the hatchery ponds. However, this only occurs when water is present and this

is only after significant rain events.

Bore water is primarily sourced from the deep bore located in the north western corner of the property

(GW401188) and is pumped through a PVC pipe network to the ponds.

Water that is used in the hatchery building is discharged to an unlined channel which runs along the inside

of the eastern and southern boundaries of the hatchery property. Surface water from the areas to the east

of the hatchery property also runoff into the channel.

A property neighbouring the hatchery was originally part of the hatchery and there are former aquaculture

ponds on the property. Residents at the property have historically drawn water from the aquaculture ponds

at the hatchery to fill ponds on their property. Water from these ponds has historically been used for

irrigation of their gardens including a vegetable garden. The residents at this property confirmed to Jacobs

that the domestic water supply for the property is RWCC water and rain water drawn from tanks on the

property that have only ever been used for rain water.

Further details of the groundwater bores at the hatchery are provided in Section 5.6.5.


IA147400-003-N-RPT-005 19

2.4.6 Forest Hill Sewage Treatment Plant

Information on the Forest Hill STP was provided to Jacobs in emails from Council on 26 and 27 June 2017 as

well as a meeting at the STP with a Council representative to gain further understanding of the process on 12

April 2018. This information is summarised as follows.

The STP is located approximately 2km north of the Base. Based on a review of historical aerial images, the

initial parts of the STP were constructed sometime between 1971 and 1980 (see Section 3.2). As noted in

Section 2.3.2.1, these initial parts appear to have been ponds for the additional treatment of partially treated

sewage from the on-Base STP. An additional plant was constructed by Defence in the 1990s to receive

untreated sewage from the Base so that the on-Base STP could be decommissioned. This plant was handed

over to Council in September, 1993.

The STP receives two sewage flows. Domestic sewage from the Forest Hill and Ladysmith communities is

pumped to the STP via a pumping station on Braehour Road (SPS22). Sewage from the RAAF base gravitates

to the STP. Some sewage flow (approximately 20 properties) from the Forest Hill and Ladysmith communities is

bypassed to the RAAF base outfall to avoid surcharging of SPS22.

Municipal sewage flow is treated through a Pasveer process which aerates sewage then allows clear water and

sludge to settle. Sludge is then transferred to two sludge lagoons, then has historically been spread as biosolids

adjacent to the lagoons and on the former landfill to the south. Clear water is siphoned into two maturation

ponds for UV sterilisation.

The sewage flow from the Base is treated in aeration ponds after passing through coarse filter bags. For

approximately the last three years, municipal waste has been transferred into the two RAAF ponds from the two

municipal maturation ponds. Combined source sewage constantly circulates through these two ponds prior to

being transferred into a third maturation pond. Combined source sewage then is transferred into a storage pond

to the north.

Historically (more than three years ago), municipal waste was combined with sewage from the Base

immediately prior to transfer into the northern storage pond. Treated water from the STP has historically been

discharged to Kyeamba Creek, irrigated on to the South Tahara Tree Plantation area as part of a CSIRO project

or irrigated on to agricultural land using a 360 degree pivot irrigator located close to the Murrumbidgee River,

directly from the municipal sewage maturation pond or from the combined sewage storage pond. Treated water

is also able to be discharged to the Murrumbidgee River from the northern storage pond. A second, pivot

irrigation area (180 degree pivot area) was trialled for approximately two months about two years ago. Some

mixing of the treated water with river water occurred prior to irrigation. The areas irrigated by the 360 degree

pivot and the 180 degree pivot are used for pasture grasses and Lucerne. The irrigation areas are shown on

Figure 6a.

Information provided to Jacobs by Council through emails on 26 and 28 July 2017 indicated that about 2 – 3

tons of biosolids are produced at the Forest Hill STP each year. Council spreads these biosolids to land around

the STP to a maximum depth of approximately 20 millimetres (mm). No other waste streams such as spent

media are produced at the STP. It is understood that sludge has not historically been removed from aeration or

maturation ponds. A small quantity of clay is understood to have historically been removed from the base of the

northern storage pond and spread on the South Tahara Tree Plantation area.

It is understood that during historical floods, floodwater has entered the STP and ponds have overflowed to the

surrounding vicinity.

Council holds an Environment Protection License for the operation of the Forest Hill STP issued by the NSW

EPA under the POEO Act 1997 (License number 1670).

The NSW EPA collected a sample of treated effluent from the Forest Hill STP in June 2017 for PFAS analysis.

Samples were also collected from the Narrung Street STP (approximately 12 km northwest of the Base) and the

Kooringal STP (approximately 6km west of the Base). These samples and the results are discussed further in

Section 7.2.


IA147400-003-N-RPT-005 20

2.4.7 Suez Liquid Waste Storage and Transfer Station

Suez operates a liquid waste storage and transfer station adjacent to the Forest Hill STP. Suez holds an

Environment Protection License for the station issued by the NSW EPA under the POEO Act 1997 (License

number 10060). The license permits the storage of up to 300 kL of waste at any particular time and permits the

following waste types:

Any waste received on site that is below licensing thresholds in Schedule 1 of the POEO Act, as in force

from time to time

Waste oil / hydrocarbons mixtures / emulsions in water (waste code J120)

Grease trap waste (waste code K110)

Sewage sludge and residues (waste code K130)

Residues from industrial waste treatment / disposal operations (waste code N205)

General or specific exempted waste

An email from the NSW EPA to Jacobs on 27 June 2017 indicated that plant consists of a series of above

ground storage tanks and was previously operated by Sita and BFI Industries. The plant has historically been a

location used to bulk up grease trap and liquid food waste for transfer to Albury for further treatment.

As noted in Section 6.2, a previous report documented concerns raised by Base personnel on the operation of

this facility given its close proximity to groundwater abstraction bores (CERAR, 2004).

Jacobs has not identified the Suez facility as a potential off-Base PFAS source based on the understanding that

the facility was primarily used for temporary storage of grease trap and liquid food waste.

2.4.8 Former landfill

There is a former landfill located immediately south of the Forest Hill STP. Environmental & Earth Sciences

(1996) reported that:

The landfill was first developed by Kyeamba Shire Council in October 1975 for disposal of putrescible

waste. Trenches were dug in the south east corner of the property approximately 50 m long, 4 – 5 m wide

and 3 – 5m deep. Waste material placed in the trenches was often burnt. The landfill was open to the

public and rarely manned.

By 1980, the area closer to the STP was developed as an urban solid waste disposal facility. This was

originally planned as a rural tip only but was used for disposal of commercial and industrial wastes such as

poultry killing works, butchers waste and dead stock. Some wastes from Tarcutta St Gas works cleanup

also may have been disposed in the 1980s. A number of trenches were located along the eastern part of

the property and a cell was located in the eastern part. Both the trenches and the cell appear to have been

developed to a depth of about 5 mBGL.

From 1988 liquid waste disposal was carried out in the trenches at the Forest Hill landfill.

In 1991, the landfill was closed during the week and was only open on weekends to the public. This

reduced amount of commercial and industrial waste.

A new liquid waste facility was installed in 1991 and this included a Claymax liner over a compacted base.

This was planned as a temporary facility for 18 months but was still being used in 1996.

Environmental & Earth Sciences (2004) indicated that the landfill was closed in approximately 2000 and clay

capping was applied. According to Environmental & Earth Sciences (1997), four groundwater wells were

installed by the Department of Land and Water Conservation in 1991 and an additional fourteen groundwater

wells were installed by Environmental & Earth Sciences in 1996 and 1997 in order to monitor groundwater

quality in the areas surrounding the landfill. The monitoring wells were installed to depths of between 10 and 16

mBGL, targeting the Cowra Formation, with the exception of two wells which were installed to depths of

approximately 6 to 8 mBGL in order to assess leachate from the landfill. Annual monitoring of these wells was

undertaken by Environmental & Earth Sciences on behalf of Council until 2004.


IA147400-003-N-RPT-005 21

None of the monitoring reports reviewed by Jacobs included sampling and analysis for PFAS. The landfill is

noted as a potential PFAS source in Section 8.2.2.


IA147400-003-N-RPT-005 22

3. Site history

3.1 Historical summary

A comprehensive review of the Base site history is documented in HLA Envirosciences Pty Ltd (HLA) Heritage

Assessment, RAAF Base Wagga Wagga (HLA, 2003) and Golder (2012a). The following summary has been

sourced from Golder (2012a) which included relevant information from HLA (2003).

Prior to 1939 the Base was used for agricultural purposes. In 1939 the Commonwealth acquired the Base land

and commenced construction of the Base. The Base was initially established as a pilot training school, and

during World War II (WWII) expanded rapidly to include numerous functions in addition to training, including the

maintenance, servicing and repairing frontline aircraft. Following WWII, the Base progressively grew into a

major training facility, with training functions expanding from pilot training, to trade training, basic recruiting, and

administration and logistics training. The Base was developed in two distinct precincts, the residential and

recreational precinct located north of the Tumbarurnba branch rail line and the instructional and flying work

areas (including airfield) located south of the rail line.

3.2 Review of historical aerial photographs

Jacobs obtained historical aerial imagery for the Base and surrounding areas from Land and Property

Information for the years 1971, 1980, 1990, 1995, 1997 and 2004. Several key images are provided as figures

in Appendix B.

Observations regarding specific areas of interest for this Preliminary CSM are noted in Table 3.1 below.

Table 3.1 : Findings from the review of historical aerial images

Year Observations relevant to this Project

1971 There appears to be structures on the area known to historically be used as a fire training

area near the runway (see red circle in image below).

There is a building located on the northern side of Barker Street, close to Newton Road.

Based on a historical site plan (not referenced and not dated) the building is noted as the

fire station (see Section 4.2). This structure is more clear in the 1990 aerial image (see

Figure 49).

There appears to be an aircraft parked in the western area of the airfield (see red circle in

image below. This area is identified in Golder (2012a) as the former Neptune plane Fire

Training Area (see Section 4.2).


IA147400-003-N-RPT-005 23

Year Observations relevant to this Project

There is an area in the north western part of the Base which is noted in Golder (2012a)

as the location of the former Base STP. The STP is not clearly visible in the 1971 image

but can be seen in the 1990 image (refer Figure 50). Note that this conflicts with the

location of the former STP reported in Golder (2012a). This is discussed further in

Section 6.6.

An area of ground disturbance is visible in the south east corner of the airfield.

There appears to be a number of surface water ponds present in the area where the

Murray Cod Hatchery is now located.

1980 The structures apparent in the 1971 image in the area used as a fire training area near

the runway now appear to have been removed and only the concrete slab is present.

While not clear in the photo, the Neptune plane appears to be present.

Additional surface water ponds are apparent in the Murray Cod Hatchery.

The Forest Hill STP is present.

Residential subdivisions in the Forest Hill area have expanded.

1990 A large area of ground disturbance is present in the south western corner of the airfield.

The Neptune aircraft is not present.

Continued expansion of the Forest Hill residential area.

1995 The former fire station appears to have been demolished.

The fire extinguisher training pad appears to be present.

The Base STP appears to have been removed.

Construction of the Brunslea Park subdivision on the eastern side of Elizabeth Avenue is

underway.

1997 No findings relevant to this investigation

2004 No findings relevant to this investigation


IA147400-003-N-RPT-005 24

4. Use of AFFF at the Base

4.1 Current use of AFFF at the Base

4.1.1 Base fire station

As noted in Section 2.2.1, Defence provides Aviation Rescue and Fire Fighting (ARFF) services for the Base

including the WWCDA. A fire station with two fire vehicles is located at Barker Street (Defence asset number

98). An email from the Base EMOS contractor to Jacobs dated 20 July 2017 indicated that the current fire

station was constructed in 1993.

The fire vehicles are fitted with AFFF tanks. AFFF product is stored on bunded pallets in a covered shed

(Defence asset number 107). The product is delivered in 200 L drums for filling of the fire vehicles. There is also

storage of AFFF in 20L containers which are used with fire hose reels in the aircraft hangars at the base

(Aurecon 2009).

An email from the ARFF contractor, Broadspectrum, to the Base EMOS contractor dated 1 August 2017 stated

that the AFFF product currently used at the Base is Ansulite 6%. Broadspectrum also stated that the fire

vehicles are filled utilising a small pump, the foam is decanted from the drum and pumped directly into the

vehicle. This is a closed looped system. The drums are normally left on the spill pallets in the covered shed area

during the filling process. Maintenance of the fire vehicles is currently undertaken by Broadspectrum in the fire

station. Broadspectrum stated that generally the foam tanks are not emptied and flushed clean, however if

required, the tanks are decanted into a 1000 L Intermediate Bulk Container (IBC) and then pumped back into

the vehicle as required.

Information provided by a former employee at the Base indicated that maintenance of the fire fighting vehicles

was historically performed by the Defence Motor Transport Group (MTG) in Building 83.

4.1.2 Fire Extinguisher Concrete Pad

There is a purpose built Fire Extinguisher Concrete Pad for fire training (RMV0098; asset number 474) located

on the opposite side of Barker Street from the fire station. The training area was constructed in 2004 to enable

training in the use of AFFF from the fire vehicles in a controlled environment so that training at the fire training

area on the airport could cease (see Section 4.2) (EarthTech, 2005). The facility consists of a concrete pad with

a 4m high wall on three sides. Diesel is used to set fires in the training area. There is a floor drain in the

concrete pad which drains wastewater collected in the pad to underground waste water storage tanks. The

tanks are pumped out by a waste contractor once full. Details of the capacity and construction of these tanks

have not been available in the information reviewed by Jacobs.

The pad is also used by fire trucks where personnel spray water jets at the wall. The force of the jets is such

that the water stream overtops the height of the wall and has caused the grouting between the bricks that

comprise the wall to erode allowing the water to pass through (Aurecon, 2009).

Aurecon (2009) also noted the following findings in relation to the facility:

There is a 3% fall from the central pit drain to the drain in the back corner of the training pit. The training pit

drain is located near the top of the pit such that it causes water to pool at the bottom of the pit. The drain

becomes blocked easily and does not appear to have adequate capacity to drain the water produced

during training exercises. The drain that leads to the stormwater system is much higher than the drain that

leads to the tanks so the only time that water drains to stormwater is when the tanks are full. The waste

water will go to stormwater if the tanks are full. Aurecon (2009) noted that the stormwater ultimately

discharges in the Murrumbidgee River. Drainage flows are discussed in Sections 2.3.3 and 5.1.

When the gate to the pit was opened during the inspection, there was a noticeable odour and visual

evidence of a sheen on the water (suggesting petroleum hydrocarbons). Aurecon (2009) recommended

that when the tanks are pumped, that the pit is also pumped.


IA147400-003-N-RPT-005 25

The asphalt apron that leads from the fire pit to where the fire vehicles pull up for training, has numerous

cracks in the pavement and is in poor condition. The asphalt was not designed to carry traffic and the fire

truck is too heavy to be parked on it. Bollards have been erected at the driveway leading to the training pit

to prevent any vehicle driving up and parking next to the pit. Vehicles have to park 20 m away on the

driveway and operate the water cannon from there. This results in some leakage from the truck when

spraying water.

It was noted that there had previously been problems with the waste water storage tanks. Previously, the

pumps that transferred the waste water across the tanks did not operate at the right time which caused the

tank to overflow. This resulted in localised contamination of the surrounding area. It was thought that

potentially there was a waste build up that choked the floating alarm that activated the pumps. The parts

have all been replaced following the contamination incident (September 2008). No information pertaining to

the contamination incident were identified by Jacobs during the review process.

The onus is on Spotless personnel and firefighting personnel to watch for the light that signals that the

tanks are at capacity. Once it has been established that the alarm light is flashing, the waste contractor is

called and the waste pumped out (approximately a 2-3 day time frame to respond to the request for

service) for disposal off site. It was noted that it costs approximately $9,000 to have the tanks emptied. The

waste water storage tanks need to be emptied at a frequency of approximately once per year. The storage

tanks have been pumped out once in the last 18 months. When the tanks were emptied there were 2-3

vehicle loads with an approximate total of 15,000L.

Due to design deficiencies, the area is only used for fire extinguisher training. The testing of fire vehicle foam

equipment is not undertaken in the facility (Aurecon, 2009). No AFFF use from fire vehicles has ever been

undertaken in this area (EarthTech, 2005).

4.1.3 Remote training

WWCDA personnel advised Jacobs that a joint training exercise is held every two years where WWCDA and

Defence fire fighting personnel respond to a mock fire at the airport. It is understood that hand held

extinguishers containing AFFF are used, or were historically used during these exercises. The WWCDA

personnel identified a location where one training exercise occurred (close to an earthing point near Taxiway A,

see Figure 6b). No further information on remote training locations was available.

4.1.4 Fire suppression or deluge systems

Several of the hangars at the Base have fixed fire suppression systems. However, these systems use water

only. As noted in Section 2.2.3, there are two bulk fuel facilities at the WWCDA. There are no current AFFF

installations at these facilities. Storage of a protein based fire fighting foam was previously undertaken at the

Mobil facility.

4.1.5 Portable fire equipment

There are 20L containers of AFFF used with fire hose reels in hangars at the Base. There are also 9L and 20L

fire extinguishers with AFFF used throughout the Base. An email from the Base EMOS contractor to Jacobs

dated 20 July 2017 stated that the AFFF used in these assets is currently Ansulite and that the assets were

pressure tested in 2009 and 2014.

4.2 Historical use of AFFF at the Base

It is understood that the AFFF product used at the Base historically was 3M Lightwater. This product was used

from approximately 1970 to 2005.

The following areas where AFFF was historically used have been identified through the information review:

1) Former fire station. The original facility is understood to have been located on the northern side of Barker

Street, in the area currently occupied by the fire extinguisher training area and extending eastward toward

Newton Road. Information supplied to Jacobs in an email from the Base EMOS contractor dated 20 July


IA147400-003-N-RPT-005 26

2017 confirmed this location and noted that the building was previously referenced as Building 232. The

EMOS contractor personnel advised that the fire station was likely demolished in 1992 or 1993. The

building is visible in the historical aerial image from 1971. Review of other historical aerial images by

Jacobs indicated that the station was demolished sometime between 1990 and 1995. Earth Tech (2005)

reported that the area was remediated in 1999 due to significant petroleum hydrocarbon contamination and

proposed facility upgrade. EarthTech (2005) reported that the initial upgrade of the area included the

installation of a concrete pad, drainage sumps and an above ground separator. This was extended in 2004

to the current training area. No information on the remediation performed in 1999 was available.

2) A former fire training area (RMV0093) was located adjacent to the eastern end of the runway. The former

training area consisted of a grassed area adjacent to a concrete pad which was used to simulate incident

response and test fire equipment. Testing drills were undertaken approximately once a month, during

which AFFF was sprayed onto the grassed area surrounding the concrete pad followed by washing of the

equipment with water, which also drained onto the grassed area. Use of this area for training purposes

ceased in 2004 when the fire training area now referred to as the Fire Extinguisher Concrete Pad was

commissioned (EarthTech, 2005).

3) A former fire training area was located near the western boundary of the airfield. Information reported in

Golder (2012a) indicated that an old Neptune aircraft was parked in the area and was set alight with diesel,

petrol or kerosene for fire training purposes. As noted in Section 3.2, an aircraft was observed to be

parked in this area in the 1971 aerial photo reviewed by Jacobs. Golder (2012a) also reported an aircraft in

this area in a 1973 photo. The fire training area is shown in an undated historical aerial photo provided by

the RAAF Base Wagga Heritage Centre, see Figure 4.1 below.

4) The apron south of building 88 was noted in a hand mark-up site plan (Defence, n.d.) received from

Defence as an area where AFFF was discharged. No further information on the use of AFFF in this area

was available.

5) Interviews with former personnel at RAAF Base Wagga identified three historical incidents involving fires at

the Base:

a) Controlled burn at the Apprentice’s Club in 1985. A controlled burn was conducted as part of the

demolition of the club. A photo of the burn is provided in Figure 4.2. The former fire personnel stated

that it is unlikely that AFFF would have been used to extinguish this building fire. The area where the

building was located is currently an open space, grassed area. This is regarded as a potential PFAS

source. The location is presented on Figure 6b.

b) Fire in the Airmen’s mess kitchen between 1960 and 2002. A minor fire occurred in the kitchen and

was extinguished with a hand held foam fire extinguisher. No significant damage to the kitchen or

dining hall occurred. Given the minor nature of the fire, this area has not been identified as a

significant potential PFAS source.

c) Fire in a residential building on Gray Street between 1960 and 2002. A fire occurred in one of the

residential apartments in a building on Gray Street. The former personnel were not sure if the fire was

in the building formerly located to the north of Gray Street or the building formerly located to the south

of Gray Street. Both buildings have been demolished. The area to the south of Gray Street is an open

space grassed area. The area to the north of Gray Street has been developed for a car park with

asphalt. The former building locations on both sides of Gray Street are regarded as a potential PFAS

source. The location is presented on Figure 6b.


IA147400-003-N-RPT-005 27

Figure 4.1 : Historical photo of the former Neptune aircraft fire training area (provided by the RAAF Base Wagga Heritage

Centre, not dated)

Figure 4.2 : Controlled burn of the Apprentice’s Club in 1985 (provided by the RAAF Base Wagga Heritage Centre)


IA147400-003-N-RPT-005 28

5. Environmental setting

Prior to preparing the SAQP for the DSI, the environmental setting of the Base and surrounding area was

conceptualised from information available in the public domain and relevant site specific reports provided by

Defence. The following summarises the outcomes of this study and provides context to the design of the field

program.

5.1 Topography and drainage

Regional topography comprises ridges and minor tablelands stepping down westwards and breaking into

detached hills with intervening alluvial valley floors. The Base is situated within the Murrumbidgee Valley and

therefore the local topography is relatively flat and has acted as the floodplain for the Murrumbidgee River. The

elevation of the Base ranges from approximately 225 metres Australia Height Datum (m AHD) in the south east

corner to approximately 210 m AHD in the south west corner.

The Base is situated within the Murrumbidgee catchment, approximately 4km south of the Murrumbidgee River,

which flows east to west. Flow in the Murrumbidgee River is regulated by Water NSW through water releases

from Blowering Dam and Burrinjuck Dam. The flow is regulated to provide water for irrigators and for

environmental flows.

River water level data for the period 2013 – 2017 sourced from the Office of Water is presented in Figure 5.1.

The data indicates water levels are generally higher during the summer months of peak irrigation. Flooding in

September and October 2016 resulted in the river height reaching 9 m. A significant release of water for

environmental purposes in August 2017 caused a peak just over 4 metres.

Figure 5.1 : Murrumbidgee River water levels at Wagga Wagga (2013 – 2017) (Office of Water, 2018)

Kyeamba Creek is a tributary of the Murrumbidgee River and is situated approximately 2.5 km to the east of the

Base. Kyeamba Creek flows northwards. Flow in the creek is intermittent. Data from the Office of Water stream


IA147400-003-N-RPT-005 29

gauging station on Kyeamba Creek at Ladysmith (approximately 12 km south east of the Base) over the

previous five years is presented in Figure 5.2. Flow ceases in the creek when the stream height is 0.86 m. The

data indicates periods of no flow generally between February and May each year. No flow and generally very

little standing water in Kyeamba Creek between the Sturt Highway and the Murrumbidgee River was observed

by Jacobs in April, 2018. This also aligned with anecdotal information provided by landowners in the area that

there was no flow in the creek during this period each year.

Farm dams east of the Base appear to be perched dams fed by surface water only. During periods of high

rainfall and flooding, water could drain from the farm dams into Kyeamba Creek at a point north of Sturt

Highway.

Figure 5.2 : Stream gauging data at Kyeamba Creek near Ladysmith (Office of Water, 2018)

Gregadoo Creek is located approximately 1.2 km west of the Base. This appears to be an ephemeral water

course that flows in the direction of Gumly Gumly Wetland and / or Marshalls Creek (approximately 6km north

east of the Base) during periods of high rainfall.

Gumly Gumly Wetland is located 1 km north west of the Base. This also appears to be ephemeral with several

farm dams located within the wetland area. The wetland and surrounding area is used for grazing of beef

livestock.

Surface water drains from around the south western corner of the Murray Cod Hatchery and from the Lake

Albert area in ditches or formalised channels to Marshalls Creek which discharges to the Murrumbidgee River

approximately 8km north west of the Base. The cross section of Marshalls Creek varies. The section from

Kooringal Road to the Murrumbidgee River is deeper, wider and more naturalised than the sections upstream of

Kooringal Road.


IA147400-003-N-RPT-005 30

Topographical contours and inferred drainage paths from the Base are presented on Figures 3a and 3b.

5.2 Rainfall

Rainfall is potentially the most significant meteorological factor that can influence PFAS conditions. The mean

monthly rainfall (measured at Bureau of Meteorology (BoM) gauge 072150, Wagga Wagga AMO) is presented

in Figure 5.3 below. The annual mean rainfall is 572.6mm and rainfall is spread evenly across the year, with

slightly increased rainfall in the May to October months.

Figure 5.3 : Mean monthly rainfall (mm) at Wagga Wagga AMO 1941 - 2017

The daily rainfall and long-term Cumulative Rainfall Deviation (CRD) (calculated) is shown on Figure 5.4 for the

period 2000 to 2017.

The long-term CRD is formulated by subtracting the average monthly rainfall for the recorded period (1941 to

2017) from the actual monthly rainfall and then accumulating these residuals over the assessment period.

Periods of below average rainfall are represented as downward trending slopes while periods of above average

rainfall are represented as upward trending slopes.

Whilst the daily rainfall shows a reasonable degree of consistency since 2000, the CRD shows that the period

2001 to 2010 typically comprised below average rainfall. This period is often referred to as the Millennium

Drought. There was a marked change in the two years from 2010 to 2012. The periods of high rainfall and

vertical CPD associated with the floods in late 2010 and in March, 2012 can be seen. Over recent years, rainfall

levels have remained roughly around the long-term average.


IA147400-003-N-RPT-005 31

Figure 5.4 : Daily rainfall and CRD 200 to 2017

5.3 Prevailing winds

Prevailing winds can influence spray drift from fire fighting activities or irrigation. Wind roses from the BoM

Wagga Wagga AMO station are presented in Figure 5.5 below. The wind roses indicate that the prevailing wind

in the morning (9am) is from the east while in the afternoon (3pm) the prevailing winds are from the west and, to

a lesser extent, the south west.


IA147400-003-N-RPT-005 32

Figure 5.5 : Wind roses for 9am (left) and 3pm (right) observations at the BoM Wagga Wagga AMO station

5.4 Geological setting

The 1:100,000 Wagga Wagga and Kyeamba Valley geological map (Raymond 1993), published by the

Australian Geological Survey Organisation, shows that the geology underlying the Base and surrounding area is

indicated as comprising alluvial and colluvial deposits of Cainozoic age. In the vicinity of the Base, the alluvial

and colluvial deposits are underlain by Wantabadgery granite of early Silurian age.

An extract from the 1:100,000 Wagga Wagga and Kyeamba Valley geological map with the location of the Base

and Gumly Gumly Wetland is shown in Figure 5.6. The published surface geology shows the alluvial deposits

(Cza), which are laid down by the Murrumbidgee River system and the colluvial deposits (Czg) that tend to be

accumulations at the base of slopes and represent sediments washed down by rainfall and the action of surface

water drainage. These processes would happen simultaneously and where the deposits meet, they would be

overlapped and interlaced and comprising very similar material such that a definite boundary can be difficult to

identify. The boundary between the two deposits shown on Figure 5.6 is likely to have been inferred from

topographical gradients and/or aerial photography so the location of which is approximate as depicted by the

dashed line.

Due to the nature of the depositional environment, alluvial deposits are generally known to be better sorted

compared to colluvial deposits leading to more defined stratification within the alluvium.


IA147400-003-N-RPT-005 33

Figure 5.6 : 1:100,00 geology map with approximate locations of the Base and Gumly Gumly Wetland (adapted from Raymond, 1993)

5.4.1 Alluvial and colluvial deposits

The alluvial deposits associated with the Murrumbidgee River are sediments laid down by water movement,

particularly during historic flooding events and are up to around 80m thick in the Wagga Wagga region. From

review of publicly available drilling logs (BoM, 2017a) the alluvium shows considerable variation in composition.

In general, coarser grained sediments are found towards the base of the alluvium and closer to the

Murrumbidgee River and the upper portion is dominated by clays and silts with a surficial clay layer present

throughout the region.

With increasing distance from the Murrumbidgee River the energy of the depositional environment decreases.

Towards the south and the area around the Base the alluvium formation becomes increasingly dominated by

clays and silts with a clear reduction in the number of groundwater bores indicating reduced potential for water

supply.

The extensive use of the alluvium for groundwater supplies within the region and the observation that there is a

general coarsening of the sediments towards the base of the alluvium has led to further delineation of the

alluvium (HLA, 2002; Mitchel, 2009) as comprising the Cowra Formation, underlain by the Lachlan Formation.

The Cowra and Lachlan definition is not shown on the 1:100,000 Wagga Wagga and Kyeamba Valley

geological map and the origin of the terminology is not clear. However, previous investigations in the region

have acknowledged and described the two formations.

The Cowra Formation is documented as mainly comprised of silts and clays with horizons of sands and gravels.

Each depositional layer is of varying and inconsistent thickness and is often laterally impersistent forming

discrete lenses.

RAAF Base Wagga

(approximate location)

Gumly Gumly

Wetland


IA147400-003-N-RPT-005 34

The basal sediments within the alluvium are shown on publicly available drilling logs to comprise coarser

grained sediments such as gravels and sands with lenses of clays and silts. This formation is known locally as

the Lachlan Formation (Mitchell, 2009) and groundwater abstraction within the region targets these sediments.

From publicly available drilling logs of local bores (BoM, 2017a), the alluvial/colluvial formation appears to be

around 60 m thick in the area around the Base. The most recent depositional layers (known locally as the

Cowra Formation) appear to reach a depth of approximately 20 m. The remainder of the sequence is the

coarser grained Lachlan Formation however there is no distinct boundary except some references to a change

in colouration from red/brown sediments in the upper portion to grey sediments in the lower portion. The poorly

sorted nature of colluvium reduces the likelihood of horizons being continuous, which would result in decreased

hydraulic connectivity compared to better sorted or more stratified formations.

In areas close to the Murrumbidgee River the publicly available drilling logs show a surficial clay layer underlain

by sequences dominated by sands and gravels with intermittent clay layers. In such logs the inferred boundary

between the Cowra and Lachlan Formations would be amongst sands and gravels and would therefore not

depict two formations with distinct properties.

The presence of the surficial clay layer in the vicinity of the Base is supported by the findings of investigations

undertaken by Golder Associates (2012b), comprising the drilling of 70 boreholes. The logs show a consistent

surficial clay layer to be present across the Base, which is the uppermost layer of the Cowra Formation.

5.4.2 Wantabadgery Granite and surrounding Sedimentary sequence

The granite exists as an intrusion into the surrounding sedimentary sequence which comprises interbedded

siltstone, shale, phyllite, schist and quartzite of Ordovician age (Raymond, 1993).

The sedimentary sequence is outcropping immediately to the east of the site as shown in Figure 4 and overlies

the granite. The thickness of the sedimentary sequence increases to the east.

5.5 Preliminary conceptual hydrogeological model

5.5.1 Hydrostratigraphy and hydraulic properties

The hydrostratigraphy at the Base and surrounding areas can be considered to comprise two units: the

alluvium/colluvium (which, in parts, can be further defined as the Cowra Formation and Lachlan Formation) and

the underlying Wantabadgery Granite.

The hydraulic properties of these units are expected to generally result in a reasonable degree of vertical

hydraulic connectivity between the Cowra and Lachlan Formations, which would vary spatially and is expected

to be greatest close to the Murrumbidgee River where the sediments are coarser and reduced away from the

river. Vertical hydraulic connectivity between the alluvium and the Granite is expected to be limited. As such, the

hydrostratigraphy can be broadly considered as two independent hydrostratigraphic units. RWCC has noted

that the apparent vertical connectivity is present in the East Wagga Borefield bores but less so in the north and

west borefields.

5.5.1.1 Cowra and Lachlan Formations

The stratification within the alluvium leads to vertical and lateral variation in hydraulic properties such that the

alluvium as a whole cannot be considered as one homogenous and isotropic unit. Previous reporting and

publicly available borelogs show that basal layers (Lachlan Formation) will have enhanced hydraulic properties

compared to the upper layers (Cowra Formation) due to the increased presence of coarser grained sediments.

Such deposits are unconsolidated and therefore groundwater will exist and move within the interstitial pore

spaces between the grains of sediment, known as primary porosity. The amount of primary porosity space

available increases with grain size and will therefore be greatest in the gravels and sands and lowest in the

clays and silts.


IA147400-003-N-RPT-005 35

The lateral movement of groundwater will predominantly take place in the higher permeability horizons of the

Lachlan Formation where sand and gravel are present; however these horizons vary in their thickness and

lateral persistence.

Public borelogs indicate that the geology in the region around the Base consists of up to 20 m of clays and silts

of the Cowra Formation. Investigations by Golder (2012b) identified that a large proportion of the Base

consisted of surficial clay soils in the upper 3 m. Based on typical hydraulic properties of clay, this is considered

to substantially attenuate vertical hydraulic connectivity between the ground surface and the underlying

permeable horizons.

Publicly available water level information shows that in some cases the overlying clay can be considered a

confining / semi-confining layer whereby the groundwater in the underlying sands and gravels is under

pressure. The pressure head is typically created where the sand and gravel layers are at a higher elevation in

the surrounding area. Where a confining clay layer is present; the water level in a well that penetrates the

underlying sand/gravel will sit above the top of the sand/gravel. This level is known as the potentiometric

surface and can be defined as the level to which groundwater will rise in the absence of a confining layer.

The hydraulic connectivity and vertical movement of groundwater between the discrete higher permeability

horizons is governed by the hydraulic properties of the interbedded clay and silt strata. Where present in

sufficient thickness, these low permeability horizons will permit only negligible movement of groundwater.

However, these too are laterally impersistent and where their presence is less significant or their hydraulic

properties are enhanced by coarser grained sediments a localised increase in hydraulic connectivity throughout

the alluvium will occur. Furthermore, it is noted that there are a large number of registered bores in the region

and these may act as vertical migration pathways for groundwater within the alluvium depending on where they

are screened and the integrity of the bore construction.

The public borelogs indicate that most bores have not penetrated beyond the alluvium. This demonstrates that

the sand and gravel horizons are of sufficient hydraulic conductivity and lateral extent to furnish local water

supplies.

DPI maintains bore GW025383 for monitoring of groundwater levels. The bore is located approximately 2.5km

north east of the Base, on the eastern side of Kyeamba Creek, and has a final depth of 66.4 m where granite

was encountered. The bore contains three nested wells with screened sections at 12.1 to 18.1 mBGL (pipe 1),

24.3 and 30.2 mBGL (pipe 2) and 54.2 to 60.2 mBGL (pipe 3). The borelog indicates the presence of a clay

layer between approximately 30 and 40 mBGL. Therefore, the screens for wells 1 and 2 are considered to be in

the Cowra Formation and the screen for well 3 is considered to be in the Lachlan Formation. Water level data

for the three wells within bore GW025383 from approximately 1971 to 2015 is presented in Figure 5.7. The data

indicates a close correlation between the water levels in all three pipes, demonstrating vertical connectivity

throughout the alluvium in this area.


IA147400-003-N-RPT-005 36

Figure 5.7 : Historical water level data (metres above sea level) from bore GW025383 (Office of Water data)

It should be noted that data regarding the yield of local water supply bores has not been reviewed with the

exception of the RAAF Wagga water supply bores. HLA (2002) documents that the test pumping results from

these bores state yields of 5 to 30 litres per second (L/s).

5.5.1.2 Wantabadgery Granite

The underlying granite is considered to be massive with some degree of fracturing. Granite typically has

negligible or very low primary porosity with groundwater storage and movement being governed by geological

structures such as fractures, faults and dykes, known as secondary porosity. Such structures tend to be

inter-connected in both the vertical and horizontal planes creating a lattice that provides conduits for

groundwater movement.

The rate of groundwater movement via secondary porosity is dictated by the aperture size and connectivity

between structures. Where these properties permit; groundwater movement can be rapid along specific

structures.

Should a water supply be sought from such a formation then the yield would be dependent on the number, size

and connectivity of the fractures intercepted by the bore. The lack of water supply bores in the region installed

within the granite may indicate that this unit does not have sufficient hydraulic properties to furnish local

supplies making the alluvium more favourable.

5.5.2 Groundwater levels and flow regime

As stated in Section 5.5.1, the alluvium and granite are assumed to be two separate hydrostratigraphic units.

The following section details the conceptual understanding of groundwater levels, hydraulic head, recharge and

discharge based on well and water level data publicly available via the BoM groundwater database (BoM,

2017a).


IA147400-003-N-RPT-005 37

5.5.2.1 Cowra and Lachlan Formation

Site investigations (Golder, 2012b) have shown the clay unit of the upper Cowra Formation on the Base to be

predominantly unsaturated. Occasional isolated areas of perched groundwater may exist, however these are

likely to be ephemeral, associated with fill material, laterally discontinuous and unconnected to the deeper

alluvial aquifer.

The regional water table within the alluvium is predominantly associated with the Lachlan formation and is

therefore typically located deeper within the alluvial sequence.

Figure 4 shows contoured groundwater levels based on the water level data available on the BoM groundwater

database (BoM, 2017a). The contours indicate a regional hydraulic head gradient towards the Murrumbidgee

River.

In the vicinity of the Base, groundwater flow is shown to be to the north west, which is consistent with the local

flow direction of the Murrumbidgee River. The contours indicate that depth to groundwater within the alluvium

ranges from approximately 30 to 40 mBGL in the south east portion of the Base to approximately 20 mBGL in

the north western portion of the Base. HLA (2002) documents that the water levels in RAAF Base Wagga water

supply bores, situated north west of the Base, was in the order of 10 mBGL, which approximately correspond

with the contouring.

Recharge to the alluvial aquifer will be via rainfall on areas where more permeable horizons are outcropping at

the surface and via the water courses when their levels are sufficiently high to cause a gradient away from the

watercourse and into the groundwater; known as a losing river. O’Neil (2007) notes that flooding of the

Murrumbidgee River is a key source of recharge to both the Cowra and the Lachlan Formations in this region. In

the immediate vicinity of the Base it is thought more likely that there will be negligible direct rainfall recharge due

to the surficial clay layer and the majority of rainfall will runoff via surface drainage.

Discharge from the alluvium will be via base flow to the Murrumbidgee River and its tributaries (gaining

watercourse), in regions where there is groundwater/surface water connectivity. This will not necessarily occur

consistently along the water course but will preferentially occur where the bed is in contact with higher

permeability sediments. In some stretches base flow will not occur or the watercourse may discharge to the

alluvium.

The relationship between the Murrumbidgee River and the underlying alluvial aquifer is dependent on their

respective hydraulic pressure heads. There will be exchange between the two systems across the alluvial

sediments near the river bed, the magnitude and direction of which will fluctuate seasonally and spatially and

will also be influenced by groundwater abstraction from the alluvium. In areas that are heavily abstracted a

reduction in baseflow to the river is likely, particularly during extended dry periods.

The modelling work carried out by O’Neil (2007) suggests that in general there is a good degree of hydraulic

connectivity between the Murrumbidgee River and Cowra Formation and between the Cowra and Lachlan

Formations. As described above this connectivity is spatially variable and O’Neil suggests that in the region of

the RWCC water supply bores there is enhanced connectivity between the Cowra and Lachlan Formations,

particularly in the East Wagga Borefield. Where these circumstances exist, water abstraction from the Lachlan

Formation will draw water from the Cowra Formation, which will in turn draw water from the Murrumbidgee River

if the river is connected to groundwater. In places where the river is not connected to the groundwater there is

expected to be downward leakage from the river into the Cowra formation but the rate of this would not be

affected by groundwater abstraction.

O’Neil (2007) calibrated the groundwater model over a 30 year period (1975 to 2005). The water balance

indicates that the abstraction from the Lachlan Formation has increased during this period, whilst the rainfall

recharge and flood events have decreased. These factors have been attributed to a reversal of the hydraulic

gradient between the river and Cowra Formation, whereby the river was gaining from 1975 to 1985 and was

losing from 1985 to 2005. The net annual loss from the river to the Cowra Formation is estimated at 7.9 GL/yr

(O’Neil, 2007).


IA147400-003-N-RPT-005 38

5.5.2.2 Granite

There is little data available on groundwater within the granite as this formation is not typically utilised for water

supply within the area. Much of the local high ground is comprised of granite outcrops and will receive direct

rainfall, some of which will recharge the granite aquifer via the geological structures that have surface

expressions. Most of the rainfall on the granite outcrops is expected to run off over the surface and contribute to

the local watercourses.

There will be some degree of vertical connectivity between the alluvium and the granite and the local variation in

hydraulic gradient will drive water movement between the two units.

5.5.3 Groundwater quality

5.5.3.1 Cowra Formation

The water quality of the Cowra Formation will vary depending on the degree of connectivity with the

Murrumbidgee River and local variations in the permeability of the formation. Fresher water will be introduced to

the formation where there is exchange across the river bed and where higher permeability zones permit

enhanced rainfall recharge. Lower permeability sediments have longer groundwater residence times, which lead

to a deterioration in groundwater quality.

Mitchell (2009) documents the salinity (as TDS) of the Cowra Formation groundwater in the region of Wagga

Wagga as being typically less than 1000 mg/L, which is considered fresh (EPA, 2015), however would

constitute poor quality drinking water. Such water would furnish a supply for stock, industrial, non-potable

domestic and irrigation depending on crop salt tolerance.

5.5.3.2 Lachlan Formation

The water quality of the Lachlan formation is known to be fresher than that of the Cowra formation and, given

the increased groundwater yields from this formation, makes this formation favourable for water supply. The

enhanced hydraulic properties permitted by the coarser grained sediments lead to shorter groundwater

residence times and increased rainfall recharge.

Mitchell (2009) documents the salinity (as EC) of the Lachlan Formation groundwater in the region to range

from 150 to 900 µS/cm (equivalent to approximate TDS: 75 to 450 mg/L). This would be considered good to fair

quality drinking water.

5.6 Local groundwater users

Figure 4 shows the registered groundwater bores and the usage type based on information extracted from BoM

(2017a). There are a number of bores that are down hydraulic gradient of the Base that will have a potential

hydraulic connection with the Base. Jacobs investigations in the area has found that the accuracy of these

records is highly variable and many bores are no longer accessible or are no longer used. This is further

discussed in Section 10.6.2.

5.6.1 Water use survey

A water use survey was conducted for the area around the Base. This involved a mail out of a water use survey

form which asked property occupiers or owners if they used groundwater or surface water at their property.

Where groundwater or surface water is used, the respondent was asked to provide details of the usage.

Survey forms were sent to a total of 1,097 properties in the week commencing 7 August 2017. The area

surveyed was slightly larger than the Study Area for the DSI discussed further in Section 0 in case the Study

Area needs to be enlarged in the future. Properties immediately north of the Murrumbidgee River were surveyed

in case there were users of river water in this area.


IA147400-003-N-RPT-005 39

In addition to the survey mail-out, a link to complete the survey was provided on the RAAF Base Wagga PFAS

investigation website. Community members were also encouraged to complete water use surveys in Defence

media interviews and at the community walk-in session held to present information on the proposed DSI

sampling plan on 24 August, 2017.

A total of 154 completed survey forms were received and are summarised as follows:

136 responses were from properties where mains water is supplied. Many of these properties were in the

Forest Hill general residential area. Some responses indicated that rain water tanks were used on the

property.

10 responses were from properties that are supplied water by the Gumly Gumly Private Irrigation District

(GGPID). The GGPID is discussed further in Section 5.6.4.

3 responses were received from properties that use bore water and / or surface water and are within the

current DSI Study Area. Sampling and analysis for PFAS was undertaken for each of these water sources

as part of the DSI.

5 responses were received from properties that are outside the current DSI Study Area.

5.6.2 RAAF Base Wagga bores

As noted in Section 2.3.1, Defence installed two off-site groundwater bores (Bore 1 and Bore 2) in 1963 in

order to provide water supply to the Base. A third off-site bore (Bore 3) was installed in 1967 as a result of

capacity problems with the existing bores and the Base was also connected to the RWCC main at Braehour

Street. Bore 2 collapsed in 1973 and was replaced by Bore 4 in the same location. Bore 1 is noted in Cardno

(2016a) as silted and not usable while Bore 3 is understood to be in a condition where it could be

recommissioned for use. Bore 5 (also off-Base) was installed in 1976 (Cardno 2016a). It is noted that HLA

(2002) states that anecdotal information indicated that Bore 5 was installed in the late 1990’s. Four observation

wells are located within close proximity to the production bores (HLA, 2002).

Bore construction details based on information in the Office of Water database are presented in Table 5.1. All

bores appear to have been terminated where granite was encountered. Based on the logs and the screened

intervals, the bores are targeting the Lachlan Formation.

At the time the HLA (2002) report was prepared, the bores supplied the Base with all raw and potable water.

Other users of water from the bores were noted to include the Forest Hill STP, BFI liquid waste plant (now

Suez), CSIRO and the Metrology Station (Flushing Meadows Project) located to the north of the site. The total

volumes and uses (raw and potable) of groundwater consumed by these facilities were unknown. These users

legally tapped into Bore 5, owned and operated by Defence, for potable water use, prior to treatment. The

improvements to the system required to support this arrangement are understood to have been funded by

Council.

HLA (2002) also noted an illegal tapper is also using water supplied by Bore 5, diverting water after it had been

pumped out from the well and prior to treatment (i.e. from some point between the Bore 5 pump and the

chlorination system).

Information provided to Jacobs by the Base EMOS contractor in an email dated 1 August 2017 indicated that

water from Bore 5 is pumped to the Tower 5 storage tank and into the two reserve fire tanks at the Base at an

approximate rate of 17 L/s. Tower 5 has a storage capacity of 150,000 gallons and the fire storage tanks have a

capacity of 100,000 gallons each.


IA147400-003-N-RPT-005 40

Table 5.1 : RAAF Base Wagga irrigation bore details

Bore ID Office of Water

registration

Final depth (mBGL) Screened interval

(mBGL)

Current status

Bore 1 GW014536 50.9 44 to 51 Silted and not

usable

Bore 2 GW014736 46.3 42 to 47 Collapsed

Bore 3 GW032214 55.1 45 to 53 Not in use but

understood to be

able to be

recommissioned.

Not accessible for

sampling due to

headworks.

Bore 4

(replacement for

Bore 2)

GW030714 46.9 42 to 47 Accessible but not

in-use

Bore 5 GW047279 56.4 44 to 53 Accessible and in-

use

Observation well 1

(Brunskill Avenue)

GW014506 48.7 48 to 49 Unable to locate

Observation well 2

(near Bore 3)

GW014767 49.3 48 to 49 Unable to locate

Observation well 5

(near Bore 5)

GW047281 49.7 37 to 50 Accessible

Observation well 6

(near Bore 5)

GW047280 53.0 41 to 53 Accessible

5.6.3 Riverina Water County Council water supplies

In addition to supplying potable water to the Base, RWCC supplies potable water throughout Wagga Wagga

including Forest Hill and the surrounding areas. RWCC water is obtained from four sources:

1) Murrumbidgee River surface water intake at 91 Hammond Avenue

2) East Wagga Wagga borefield

3) West Wagga Wagga borefield

4) North Wagga Wagga borefield

RWCC verbally advised Jacobs that the primary source of water supply for RWCC is from the borefields.

Approximately 20% of total water is sourced from the Murrumbidgee River on an annual basis and 100% of

water is sourced from the borefields during the winter period.

The Murrumbidgee River intake is located approximately 8km north west of the Base, just upstream of the

Marshalls Creek confluence. The East Wagga Wagga borefield consists of two bores located along Kooringal

Road between Hammond Avenue and the Murrumbidgee River and a third bore located at the northern end of

Gillard Road. These bores are all located approximately 7km from the Base. The Murrumbidgee River intake

and the East Wagga borefield are hydrogeologically downgradient of the Base.

Construction details for the East Wagga Borefield bores were obtained from DLWC (1996) for Bore 1 and from

the Office of Water website for Bores 2 and 3. Summary information is provided in Table 5.2. Based on the logs

and the screened intervals, the bores are targeting the Lachlan Formation.


IA147400-003-N-RPT-005 41

Table 5.2 : RWCC East Wagga Borefield bore details

Bore ID Final depth (mBGL) Screened interval (mBGL)

Bore 1 (GW039573) 71.5 48 to 52 and 63 to 70

Bore 2 (GW039572) 61.2 48 to 55 and 58 to 60

Bore 3 (GW030667) 70.4 48 to 56 and 61 to 69

RWCC advised Jacobs that the water from Murrumbidgee River intake and the East Wagga Wagga borefield is

treated at RWCC facilities at 91 Hammond Avenue. The treated water from either surface and/or groundwater

(via RWCC's Waterworks facility) is then pumped into various reservoirs that form part of two pressure supply

zones (Wagga Low Level and Wagga High Level). The Wagga High Level system supplies approximately two-

thirds of Wagga including Forest Hill. RWCC's Rural Southern Trunk System that extends from Wagga Wagga

to Walla Walla (approx. 40km short of Albury) can be supplied from the Wagga Low Level System or from West

Wagga Borefield (via Shires Reservoir on Willans Hill).

RWCC has advised Jacobs that no previous testing for PFAS has been undertaken of the RWCC water supply.

The locations of the RWCC Murrumbidgee River intake and the bores that make up the East Wagga Borefield

are shown on Figure 1.

5.6.4 Gumly Gumly Private Irrigation District

The Gumly Gumly Private Irrigation District supplies water to approximately 60 users in the Gumly Gumly area,

approximately between Gumly Road and the Murrumbidgee River. The water is sourced from a groundwater

bore located close to the Murrumbidgee River and is used for domestic and irrigation purposes. The bore is

registered with the Office of Water as GW039499 and the works summary report indicates that the bore was

drilled to 85 mBGL where weathered granite was encountered. Several water bearing zones are noted on the

works summary report; 50 to 52 mBGL, 56 to 58 mBGL and 65 to 67 mBGL. Based on the log and the screened

intervals, the bore is targeting the Lachlan Formation.

The location of the bore is shown on Figure 5a.

5.6.5 Murray Cod Hatchery

As noted in Section 2.4.5, the Murray Cod Hatchery to the north west of the Base uses groundwater to supply

the aquaculture ponds. The bore currently used to supply water to the ponds is GW401188. Details of each of

the groundwater bore at the hatchery obtained from the Office of Water website and the hatchery operator are

summarised in Table 5.3. Based on the logs and the screened intervals, it is considered that the bore are

targeting the Lachlan Formation with the exception of GW402595 and GW403121 which are targeting the

Cowra Formation.

Table 5.3 : Murray Cod Hatchery bore details

Bore ID Final depth (mBGL) Screened interval

GW401188 45 39 to 45 mBGL

GW402595 16.5 14 to 16.5 mBGL

GW403121 15.5 Screen details not provided but water bearing zone

noted as 12.2 to 15.5 mBGL

GW037091 46 33 to 43 mBGL

GW401651 43 34 to 43 mBGL

No registered bore ID1 46 33 to 43 mBGL


IA147400-003-N-RPT-005 42

1 This bore is located on the western side of the hatchery building. No bore construction details were

available but Jacobs was advised by the hatchery operator that the bore was installed at the same depth

and same screened interval as GW037091.

5.7 Groundwater dependent ecosystems

The BoM groundwater dependent ecosystem (GDE) atlas (BOM, 2017b) identifies a number of potential GDEs

in the vicinity of the Base. These are broadly divided into two categories:

GDEs that are reliant on the surface expression of groundwater. This includes water courses, wetlands and

swamps.

GDEs that are reliant on the sub-surface expression of groundwater. This typically includes vegetation with

root systems that tap groundwater.

5.7.1 GDEs that are reliant on the surface expression of groundwater

A number of local rivers and creeks are shown on the GDE atlas. Given the direction of groundwater and

surface water movement, the following have been identified as having a potential hydraulic connection with the

Base:

Murrumbidgee River – largest watercourse in the region, situate to the north of site, down hydraulic

gradient and flows east to west

Kyeamba Creek – Tributary of the Murrumbidgee River flows northwards to the east of site

Gregadoo Creek – ephemeral creek that may connect with Marshalls Creek during extended periods of

high rainfall

Marshalls Creek – Tributary of the Murrumbidgee River down gradient of the site

Gumly Gumly Wetland – Appears to be ephemerally connected to Gregadoo Creek

The following sites are shown on the GDE atlas however, based on the current understanding there does not

appear to be a potential hydraulic connection with the Base:

Oura Creek – Tributary of the Murrumbidgee River situated to the east of site, up hydraulic gradient

Majors Creek – Tributary of the Murrumbidgee River situated to the east of site, up hydraulic gradient

Garcias Creek – Tributary of the Murrumbidgee River entering at the northern bank

Wrights Creek – Tributary of the Kyeamba Creek, up hydraulic gradient to the south of the site

Coxs Creek – Up hydraulic gradient to the south of the site

Boiling Down Creek – Up hydraulic gradient to the south of the site

Crooked – Up hydraulic gradient to the south of the site

Tywong – Tributary of the Kyeamba Creek, up hydraulic gradient to the south of the site

Wheel of Fortune – Tributary of the Murrumbidgee River entering at the northern bank

5.7.2 GDEs that are reliant on the sub-surface expression of groundwater

The following local Eucalyptus woodlands have been identified by the GDE atlas:

River red gums – Situated approximately 5km to the north west of the Base down hydraulic gradient. A

potential hydraulic connection is inferred between the location of this GDE and the Base.

Box-Gum woodland – Situated approximately 5km east of Base, on the eastern bank of the Kyeamba

Creek. No potential hydraulic connection is inferred between the location of this GDE and the Base.


IA147400-003-N-RPT-005 43

5.8 Ecology

Jacobs conducted an Environmental Protection and Biodiversity Conservation (EPBC) Act Protected Matters

search for the Base and a 20km buffer area through the Department of Environment and Energy. The following

items were reported:

No world heritage properties

No national heritage places

Four wetlands of international importance (ramsar), however these were all at least 400km upstream of the

Base

Three listed threatened ecological communities

Nineteen listed threatened species

Eleven listed migratory species

Seventeen listed marine species

The EPBC Act Protected Matters report is provided in Appendix C.

Information on threatened species, populations and ecological communities found in the Wagga Wagga LGA

(City of Wagga Wagga Council, n.d.(a)) is provided in Appendix D.

Information provided by DPI Fisheries has identified that there are several species of fish that are commonly

caught through recreational fishing in the Murrumbidgee River such as Murray Cod, Golden Perch, Common

Carp, Murray Crayfish and Common Yabby. It is also understood based on discussions with community

members that yabbies’ are present in farm dams which are occasionally collected for human consumption or

bait fishing. The potential for this exposure to occur and associated ecological and/or human health risk is

considered in later sections of this report (Section 13.3) as well as in the HHERA.


IA147400-003-N-RPT-005 44

6. Review of previous investigations

6.1 General

A total of 41 environmental reports are registered in the Base Contaminated Site Register (CSR), however,

several reports are listed as missing or ‘unable to locate’. Jacobs was provided with 33 environmental reports

listed in the Base CSR for review to inform this preliminary CSM. Several other Base-specific reports relating to

environmental management, heritage management, and water use and supply were also provided to Jacobs as

part of the information review process.

Of the reports made available to Jacobs, there are seven relevant CSR entries relating to the use or storage of

AFFF products at the Base or that included the investigation of PFAS, including:

University of South Australia, 2004. Phase 1 and Phase 2 Proposal - Site Assessment of RAAF Base

Wagga Wagga (CERAR, March 2004); and

EarthTech Engineering, 2005. Stage 1 Contamination Investigation of RAAF Base Wagga Wagga

(EarthTech, 2005);

Maunsell Australia Pty Ltd / CH2M Hill Australia Pty Ltd / AECOM. July 2006. RAAF Base Wagga Wagga

Stage 2 Environmental Investigation Final Report. (Maunsell, 2006)

Aurecon, 2009. Environmental Review of Fire Fighting Training and Facilities, Department of Defence,

RAAF Base Wagga - Site Report (Aurecon, 2009);

Vantage Environmental Management, 2009. Identification of Priority Pollutants, Site No. 0906, RAAF Base

Wagga (Vantage, 2009).

Golder Associates, 2012. Stage 1 Environmental Investigation (Golder, 2012a);

Golder Associates, 2012. Stage 2 Environmental Investigation (Golder, 2012b);

In addition, Jacobs were provided with the report from a preliminary sampling program which included sampling

and analysis of PFAS at several locations on the Base or surrounding areas (GHD 2016). The report was not

listed on the Base CSR, however has been included as a key information source to inform the preliminary CSM.

6.2 CERAR (2004)

CERAR (2004) was commissioned by Spotless Property and Facilities (Spotless) to undertake a preliminary site

assessment and contaminant characterisation for the Base. The site visits for the work were undertaken in

January, 2004. The objectives of the Phase 1 were to identify potential contamination issues and formulate a

sampling strategy for identifying the source, nature and extent of contamination. The Phase 1 report provided a

summary of site features and identified three locations for further environmental investigation. These locations include

a toxic waste store, burial pits alongside the runway and a demolition area.

The report is an important document as it also provided a summary of several environmental documents listed

in the current CSR as missing or ‘unable to locate’, including reference to a site audit completed at the Base by

URS Australia Pty Ltd (URS) in December 2000.

Information in URS (2000) (as summarised in CERAR, 2004) considered relevant to the current PFAS

investigation included:

In reference to the Fire Extinguisher Concrete Pad (RMV0098), URS (2000) documented that “the former

fire training facility had been remediated around 1999”. However, no further information was provided on

where or how the remedial works took place, and did not elaborate on the outcomes of the remedial works.

It is also not clear if this actually refers to the former fire station in this area or a training facility. It is noted

that additional information pertaining to the remediation of the former fire training facility is included in

Section 6.3.


IA147400-003-N-RPT-005 45

In referring to site personnel interviews, URS (2000) documented that site personnel raised some concerns

regarding a liquid waste treatment facility operated by BFI Industries. The facility was reported to be

located within 100 m of one of the commonwealth owned groundwater extraction bores. In addition, one

extraction bore was located in close proximity to a decommissioned waste tar pit, formerly owned and

operated by Council. The BFI industries facility was discussed in Section 2.4.7. The waste tar pit is

understood to be the former landfill described in Section 2.4.8.

6.3 EarthTech (2005)

EarthTech conducted a Stage 1 Investigation of the Base in May 2005. This investigation was undertaken to

appraise site history and review previous environmental sampling conducted at the Base. The investigation

considered a series of areas of environmental interest and involved interviews with selected site personnel.

Each area was uniquely identified with a registered number to be included on the CSR.

Findings considered relevant to the current PFAS investigation included:

RMV0093 (Fire Training Area), located adjacent to the eastern end of the runway. This consists of a

grassed area adjacent to a concrete pad. Based on information gained during interviews with site

personnel, this area was used once a month to test the AFFF equipment of the fire engine. The equipment

was discharged onto the grass area. Following testing the equipment was then rinsed through with water,

which was also sprayed onto the grassed area. Use of this area for training purposes reportedly ceased in

2004. This area was ranked as a high risk and further investigations were recommended.

RMV0097 (Fire Station), located off Barker Street. The area was previously used to wash down fire

engines with water and some occasional equipment testing. Drainage from the concrete drive is directed to

a sump, prior to discharging to stormwater. Based on information gained during interviews with site

personnel the area has not been used for AFFF testing. This area was ranked as a low risk, and no further

investigations were recommended.

RMV0098 (Fire Extinguisher Concrete Pad), this is located opposite the current fire station on Barker

Street. Earth Tech (2005) noted that due to historical petroleum hydrocarbon contamination, remediation of

the area had been recommended. Based on information gained during interviews with site personnel, the

area was understood to have been remediated in 1999, during the upgrade of the fire training area. The

remedial work reportedly included land farming of hydrocarbon impacted soils, however, Earth Tech,

(2005) did not elaborate on the details of the remedial works.

EarthTech (2005) reported that the initial upgrade of RMV0098 included the installation of a concrete pad,

drainage sumps and an above ground separator. This was extended in 2004 to the current training area,

which included the underground waste water storage tanks, which are pumped out by a waste contractor

once full. Due to design deficiencies, the area is only used for fire extinguisher training, and the fire engine

foam equipment is no longer tested. This area was ranked as a high risk and further investigations were

recommended.

6.4 Maunsell (2006)

Maunsell Australia Pty Ltd (Maunsell) in partnership with CH2M HILL Australia Pty Ltd (CH2M HILL) was

commissioned by Defence to undertake a Stage 2 Environmental Investigation at the Base in 2006. The works

also included a Stage 1 investigation and preliminary review of risks for additional areas of environmental

interest, not considered by EarthTech (2005).


RMV0093 (Fire Training Area): Seven soil boreholes were drilled with a hand auger. Only surface samples

were able to be collected from these boreholes due to the hardness of the ground surface. One hand auger

(HA06) investigation location was extended to 0.5 mBGL. A drilling rig was used to advance to a depth of 6

mBGL at BH4, in an attempt to intersect perched groundwater; no groundwater was intersected. Drilling was not

continued as the regional groundwater (aquifer) was expected to be at greater than 40 m depth and therefore it

was considered that the risk of migration of potential contaminants from the site to the regional groundwater was

very low.


IA147400-003-N-RPT-005 46

The Chain of Custody forms indicated that soil samples collected from RMV0093 were scheduled for

analysed for AFFF. However, laboratory certificates indicate that samples were instead screened for MBAS

as an indicator to identify potential AFFF impacts. This test is a non-specific test for anionic surfactants, a

component of AFFF. Concentrations of anionic surfactant in soils were below the laboratory limit of

reporting (LOR). No discussion of these results was included in the Maunsell (2006) report. The area was

rated as a medium risk and management control strategies were recommended.

RMV0098 (Fire Extinguishing Training Area); Three boreholes were drilled in this area to a depth of 3

mBGL. Two boreholes targeted the sealed area and a third borehole was positioned adjacent to the two

underground concrete tanks. Soil samples were screened for anionic surfactants as an indicator to identify

potential AFFF impacts. Concentrations of anionic surfactants in soils were below the laboratory LOR. No

discussion of these results was included in the Maunsell (2006) report.

Perched groundwater was identified in the vicinity of the holding tanks and a monitoring borehole (PW01)

was installed. Groundwater collected from PW01 was analysed for a range of contaminants, including

anionic surfactants. PW01 returned concentrations of anionic surfactants of 0.7 mg/L; above the ANZECC

(1992) raw drinking water guidelines. Maunsell (2006) reported the presence of anionic surfactants was likely

to be indicative of the existence of AFFF in perched water given the sites current function as a fire training area

with documented use of AFFF.

6.5 Vantage (2009)

A program to identify Priority Pollutants (PP) at the Base was conducted by Vantage Environmental

Management Pty Ltd (Vantage), with field visits on 11 December 2008.

The project involved the systematic review of documentation and localities associated with substances on the

Defence Priority Pollutant List. The following tasks occurred:

Review of the ChemAlert database.

Review of 11 selected sites that were designated within either Defence Environmental Management

System (DEMS) or the ChemAlert database.

Review of 12 selected sites that were not designated as potential sites where priority pollutants were

present within DEMS or the ChemAlert database.

Preparation of a table of actions based on project outcomes for inclusion within the Base DEMS.

The key findings of the project were:

In many locations PP substances were present that were not identified in the ChemAlert database.

Sites where PP substances were present were not listed on DEMS.

The use of the ChemAlert database across the Base was generally quite extensive and all users

commented on the comprehensiveness and value of the database as a management tool for hazardous

substances.

The only finding considered relevant to the current PFAS investigation was that approximately 500L of AFFF

(Ansulite) and 60L of AFFF (3M Lightwater) were identified in the “fire station/ armoury” (noted as Building 90).

Jacobs notes that it is unclear if the product was stored in the fire station or was in fact located in the storage

shed (asset number 107), located adjacent to building 90.


IA147400-003-N-RPT-005 47

6.6 Golder (2012a)

Defence engaged Golder to undertake a Stage 1 Environmental Investigation at the Base in 2012. The

objectives of the Stage 1 Environmental Investigation were:

The identification and assessment of contamination risks associated with the current and historic site

activities, using a “Whole of Base” approach. This includes a gap analysis of previous environmental

investigation(s) completed at the site, as well as the identification of other potential risks not previously

considered. The findings will be included the Defence Contaminated Site Register (CSR).

The assessment of the identified contamination risks and assigning an interim risk ranking using the

Defence Contamination Risk Assessment Tool.

The updating, or where necessary development, of a Property Contamination Profile using the most

accurate information available.

Identification of risks to be investigated further through a Stage 2 environmental investigation, with the

proposed scope of works presented as a Sampling and Analysis Plan with relevant Contaminants of

Potential Concern.


RMV0092 - Former Land Filling Area 1, Construction Area Waste (Post WWII Tip): This former land filling

area is located in the south western corner of the site, and covers an area of approximately 10 hectares.

Based on the review of historical aerial photographs, the area has been used for land filling from as early

as 1944. Anecdotal information presented in the previous environmental reports, has noted that this area

may have received general waste materials, surplus equipment and more recently waste from construction

and engineering works (Maunsell, 2006). Soils excavated from NSW1105 - Former Bitumen Plant and

Neptune Plane Fire Training Area have been stockpile in this area.

RMV0094 - Former Land Filling Area 2, Post WWII Waste Disposal Area: This former landfilling area is

located north of the current airport taxi ways and east of the Base Hanger Precinct. Based on the review of

historical aerial photographs, dumping commenced in this area in the period between 1944 and the 1960’s,

and continued until the 1970’s. Maunsell (2006) reported that an aluminium smelter was located in close

proximity to this area, and that smelter wastes may have been placed in this area. Information provided to

Golder during the site inspection, however, confirmed that the smelter was operated by a local contractor,

on an adjacent private property, not actually on the Base. The investigations completed CERAR (2004b),

did, however, note the presence of ash materials within burial pit number 4. At the time of the Golder 2012

site inspection the area appeared unchanged to that investigated by Maunsell (2006) the area was covered

with grasses and several of the pits were apparent due to subsidence within the pits. Test pit log data from

the CERAR (2004) Stage 2 report indicated that the average depth of these burial pits was approximately

3.5 to 4 m depth. Metal scraps, or other waste materials (as described by Maunsell, 2006) were not evident

during the inspection and the area surface appeared stable with no evidence of soil erosion occurring.

Perched groundwater was noted by CERAR (2004) at the eastern most investigated burial pit.

RMV0093 - Fire Training Area: The former fire training area was inspected on two occasions by Golder,

initially on the 25 January 2012 and then on the 20 February 2012. During the inspections the area appear

unchanged to that investigated by Maunsell (2006). Information provided during the second inspection, was

that the area was used by Regional Express (REX) to undertake engine testing, where aircraft were tied

down and the engines were “run up” to test performance. This practice was reportedly ceased, once it

became apparent that the area was not included in the WWCDA lease area

RMV0123 - Former Toxic Chemical Store: The former toxic chemical store area is located in the southern

corner of the airfield and consists of a fenced compound enclosing an open sided shed, square tank and

several soil stockpiles. The area has been the subject of several environmental investigations. Access to

the area was not granted into the fenced compound during the Golder site inspections. Staining and bare

ground was evident at the north west corner of the compound, immediately inside the compound fence.

The stockpiles of soil present within the compound appeared to include demolition waste. Golder noted that

piping, similar to that used for underground fuel storage infrastructure, was protruding from the stockpile.

The shed appears to have been used for chemical storage as the internal drainage structures were shaped

such that spills would drain to central sumps located in each storage area. The discharge of the sumps


IA147400-003-N-RPT-005 48

could not be confirmed. The evaporation tank (described in CERAR, 2004) was present in the area,

however as access into the compound was restricted and the condition of the tank could not be assessed.

RMV0170 - Railway Corridor: The former Tumbarumba branch rail line transects the site from west to east,

immediately north of current fire extinguisher training area (RMV0098). At the time of the Golder 2012 site

inspections, the rail corridor was clearly visible through the site, however no evidence of former rail lines or

associated infrastructure were evident on the site surface. The area appeared to have been landscaped,

with grass and trees planted throughout the area. A portion of the current fire extinguisher training area

overlaps across the corridor, and portions of the car parks located west of the fire training area also appear

to be overlapping onto the corridor. Historically, the former fire extinguisher training area, and former fire

training area, would also have been positioned either within the corridor, or adjacent to the corridor.

RMV0179 - Active and Abandoned Sewage Services: During the Golder site inspections, the footprint of

the former onsite sewage treatment facilities was inspected. It is understood the system consisted of

primary (screening facility) located near to the north western corner of the site and two secondary

treatment circular trickling filter tanks, located on the western boundary in the vicinity of the current

residential precinct. It was reported that the system was shut down when the site migrated to Council

sewage services, and the infrastructure was removed following this. Jacobs notes that based on our review

of historical aerial images, the former Base STP appears to have been located further to the north then the

position identified by Golder (see 1990 image, Figure 50 in Appendix B).

Building 201 and 83 - Vehicle Maintenance: Maintenance activities were reportedly undertaken by the

Defence MTG in Building 201, located in the eastern portion of the Hanger Precinct. It was reported that

these facilities are used to complete most vehicle maintenance tasks. It was also reported that vehicle

maintenance activities were previously undertaken by the MTG within Building 83, which is the current

clothing store. The current location of the MTG vehicle maintenance activities is west of Building 201,

where a covered wash down bay drains, via a triple plate interceptor, to sewer. It was reported previously

(Maunsell, 2006) that this facility would only drain to sewer when the wash down bay was in operation, the

remainder of the time the interceptor would discharge to stormwater. It was unclear at this time of the

Golder 2012 site inspection as to whether the diversion function was still in operation. Jacobs notes that

information provided by a former Base employee has indicated that maintenance of the fire fighting

vehicles was historically performed in Building 83 only.

The WWCDA Ground Crew Depot includes an open wash down bay for vehicle washing. It was reported

that the facility was used infrequently, once a week to wash vehicles. Discharge from the wash bay is

treated via an oil water separator, before being stored in an in-ground tank. Once full the contents of the

tank are discharged, via a pump and hose, across the adjacent grassed areas, east of the wash bay

facilities.

6.7 Golder (2012b)

Defence engaged Golder to undertake a Stage 2 Environmental Investigation at the Base in 2012. The

objectives of the Stage 2 Environmental Investigation were:

An assessment of the nature and extent of contamination across the Base such that the conceptual site

model developed for the site during the Stage 1 Environmental Investigation could be refined;

To determine appropriate remediation and management options with expected costs, where appropriate;

and

To provide accurate information to update the Property Contamination Profile and Contaminated Sites

Register.

A series of intrusive investigations were undertaken with a combination of methods employed to identify and

delineate contamination at the site. Sampling for PFAS was limited to the Fire Extinguishing Training Area

(RMV0098) and the Former Bitumen Plant and Neptune Aircraft Fire Training Areas (NSW1105). The results of

the sampling are summarised in Section 7.

Golder (2012b) provided several recommendations for remedial works at the Base, including, but not limited to:

Updating the site EMP to include the management of uncontrolled excavations across the site;


IA147400-003-N-RPT-005 49

Consider removing the former Toxic Waste Storage area (RMV123) infrastructure and subsequent

remediation and validation of the residual soils in the area

Consider remediation and validation of the contamination identified in the vicinity of the Fire Extinguisher

Training Facility

Consider further investigations of the character and locations of soils removed during recent construction

activities from the area of the former bitumen plan and former Neptune Aircraft Training area.

6.8 GHD (2016)

Defence engaged GHD to undertake preliminary and limited sampling and analysis of environmental media at

selected off-site locations adjoining the Base. The investigation was intended to be a snapshot of the potential

off-site presence of PFAS only, and was designed to provide an indication of the potential for PFAS to have

migrated off-site via groundwater or surface water. This was to assist Defence to meet it objective to facilitate

early identification of potential exposure risks to off-base users of groundwater for the purpose of prioritising any

future investigation.

The scope of investigation included the sample and analysis of three off-site groundwater bores owned and

operated by the Commonwealth, and two surface water localities (located either on Commonwealth land or

publicly accessible areas). The sampling was conducted in June 2016. The results of the investigation are

summarised in Section 7.


IA147400-003-N-RPT-005 50

7. Previous PFAS sampling

7.1 PFAS sampling conducted prior to commencement of the Project

A limited number of sampling programs that have included analysis of PFAS in soil, surface water or

groundwater have been conducted either on the Base or at selected off-Base locations prior to commencement

of the Project. A summary of these investigations is provided in Table 7.1.

Table 7.1 : Previous investigations which have included PFAS analysis for the Base

Report Scope of works Summary of Results

Maunsell (2006) Seven soil boreholes were drilled with a

hand auger at RMV0093 (Fire Training

Area). Only surface samples were able to

be collected from these boreholes due to

the hardness of the ground surface. One

hand auger (HA06) investigation location

was extended to 0.5 mBGL. A drilling rig

was used to bore to a depth of 6 mBGL at

BH4, in an attempt to intersect perched

groundwater; no groundwater was

intersected.

Samples screened for MBAS as an

indicator to identify potential AFFF impacts.

This test is a non-specific test for anionic

surfactant, a component of AFFF.

Concentrations of anionic surfactant in

soils were below the laboratory limit of

reporting (LOR). No discussion of these

results was included in the Maunsell (2006)

report. The area was rated as a medium

risk and management control strategies

were recommended.

Three boreholes were drilled in RMV0098

(Fire Extinguishing Training Area) to a

depth of 3 mBGL. Soil samples were

screened for anionic surfactant as an

indicator to identify potential AFFF impacts.

Perched groundwater was identified in the

vicinity of the holding tanks and a

monitoring well (PW01) was installed.

Groundwater collected from PW01 was

analysed for a range of contaminants,

including anionic surfactants.

Concentrations of anionic surfactant in

soils were below the laboratory LOR. No

discussion of these results was included in

the Maunsell (2006) report.

PW01 returned concentrations of anionic

surfactants of 0.7 mg/L, above the

ANZECC (1992) Raw drinking water

guidelines. Maunsell (2006) reported the

presence of anionic surfactants was likely

to be indicative of the existence of AFFF in

perched water given the sites current function

as a fire training area with documented use

of AFFF.


IA147400-003-N-RPT-005 51

Report Scope of works Summary of Results

Golder (2012b) Golder completed a soil and groundwater

investigation at RMV0098 (Fire

Extinguishing Training Area). Four soil

boreholes (BH125, BH127, BH128 and

BH129) were drilled to a depth of 3 mBGL.

Soil samples collected from BH127, BH128

and BH129 were analysed for PFOS,

PFOA and C2H4-perfluorooctane sulfonate

(6:2 FTS).

Golder also completed a soil investigation

in the Former Bitumen Plant and Neptune

Plane Fire Training Area (NSW1105). Five

boreholes were advanced to a maximum

depth of 3 mBGL. Groundwater was not

encountered. One soil sample was

collected from each of three boreholes in

this area (BH165, BH170 and BH171) and

these samples were analysed for PFOS,

PFOA and 6:2 FTS.

Results for the Fire Extinguisher Training

Area can be summarised as follows:

BH127 - PFOS 0.257 mg/kg, PFOA

0.0012 mg/kg and 6:2 FTS below

LOR


0.0012 mg/kg and 6:2FTS below LOR


below LOR and 6:2 FTS below LOR

Groundwater collected from PW01

PFOS 168 ug/L, PFOA 4.34 ug/L and

6:2 FTS (1 ug/L)

Results for the Former Bitumen Plant and

Neptune Plane Fire Training Area can be

summarised as follows:

BH165 – PFOS, PFOA and 6:2 FTS

concentrations below LORs

BH170 – PFOS 0.0363 mg/kg, PFOA

below LOR and 6:2 FTS below LOR

BH171 - PFOS, PFOA and 6:2 FTS

concentrations below LORs

The approximate sampling locations and

results for the soil samples are presented

on Figures 5b and 5c.

GHD (2016) The scope of investigation included the

sample and analysis of three off-site

groundwater bores owned and operated by

the Commonwealth, and two surface water

localities (located either on Commonwealth

land or publicly accessible areas).

Observation well for RAAF Base Bore 5

(GW047281), located approximately 1 km

north of the Base, had a reported

concentration of PFOS of 0.04 ug/L, below

the screening criteria for Drinking Water

(0.2ug/L) adopted by GHD (2016).

Two surface water samples (WAG_SW001

and WAG_SW002) located on the western

boundary of the Base, had reported

concentrations of PFOS of 0.1 ug/L and

0.08 ug/L respectively. The concentrations

were below the screening criteria for

Drinking Water (0.2ug/L) and Recreational

Use (2 ug/L) adopted by GHD (2016).

7.2 Sewage Treatment Plant sampling undertaken by the NSW EPA

NSW EPA carried out sampling of effluent from the three STPs operated by Council and results of the sampling

were provided to Jacobs in an email from the NSW EPA dated 10 August 2017. Based on the information

provided, Jacobs understands that one sample of treated effluent was collected from each plant and was

analysed for selected PFAS compounds. The results of the sampling are presented in Table 7.2.


IA147400-003-N-RPT-005 52

Table 7.2 : Results from NSW EPA sampling of treated effluent from Council STPs (µg/L)

PFAS compound Narrung Street STP Forest Hill STP Kooringal STP

C2H4-perfluorodecane sulfonate (8:2

FTS)

<0.04 <0.04 <0.04

C2H4-perfluorooctane sulfonate (6:2 FTS) <0.03 0.04 0.21

Perfluorobutanesulfonate (PFBS) <0.01 0.02 <0.01

Perfluoroheptanoic acid (PFHpA) <0.01 0.01 0.02

Perfluorohexanesulfonate (PFHxS) <0.01 0.16 <0.01

Perfluorohexanoic acid (PFHxA) 0.049 0.055 0.030

Perfluorononanoic acid (PFNA) <0.02 <0.02 <0.02

PFOS <0.01 0.32 <0.01

PFOA 0.07 0.02 0.03

PFOS + PFHxS <0.02 0.48 <0.02

The results of the sampling by NSW EPA indicate some PFAS compounds with concentrations above the

laboratory LOR in all three samples with concentrations in the sample from the Forest Hill STP generally higher

than the samples from the other two STPs.

The Narrung Street STP is located north of the Wagga Wagga CBD and information on the Council website

indicates that treated effluent is discharged to either the Murrumbidgee River or into the network of effluent

reuse/irrigation projects administered by the Council (CWWC, n.d. (b)).

The locations of the Forest Hill and Kooringal STPs are presented on Figure 5a. As noted in Section 2.4.6, the

Forest Hill STP treated effluent was historically discharged to Kyeamba Creek and is now evaporated and / or

irrigated to land. These irrigation areas are noted as potential secondary sources of PFAS in Section 8.2.2.

Spreading of biosolids in areas around the STP is also noted as a potential source of PFAS contamination.

Information on the Council website (CWWC, n.d. (b)) indicates that the Kooringal STP receives sewage

collected from the areas of Kooringal, Tatton, Lake Albert, and the pressure sewer from East Wagga and Gumly

Gumly. The treatment load primarily consists of domestic sewage with a light industrial area located within the

sewer catchment. Waste sludge from the Kooringal STP is digested and held in two lagoons, where it is

removed to landfill when required. The final effluent from the STP is discharged into either the Murrumbidgee

River via Marshall's Creek or into the network of effluent reuse/irrigation projects administered by Council. The

Council website indicates that the reuse includes irrigation at Rawlings Park and an onsite treelot. The effluent

discharge could influence PFAS concentrations in Marshall’s Creek and therefore this discharge is noted as a

potential PFAS source in Section 8.2.2.

It is understood that wastewater from the Base has not been treated at the Kooringal STP and therefore the

potential for PFAS impacts associated with biosolid disposal or effluent reuse at Rawlings Park from this STP

has not been further investigated at this stage.

7.3 Jacobs preliminary sampling program

A preliminary sampling program was completed by Jacobs on 20 June 2017 and 7 July 2017. The objective of

the Preliminary Sampling Program was to provide information to assist in the development of a Preliminary CSM

for the Base and surrounding areas. Point of use sampling of surface water and groundwater was undertaken at

several off-Base locations. Surface water conditions can vary significantly with rainfall and several rounds of

sampling can be required to adequately characterise this variability. Therefore, the Preliminary Sampling

Program also included the collection of surface water samples at two readily accessible locations in order to

commence the data collection.


IA147400-003-N-RPT-005 53

The scope, methodology and results from the program have been reported in more detail separately (Jacobs,

2017b). A summary of the key information is provided below.

7.3.1 Sampling locations

The sampling locations for the preliminary sampling program are presented in Table 7.3.

Table 7.3 : Sampling locations for the Jacobs preliminary sampling program

Target area Sample locations and

Primary Sample ID

Description Sample

date

Riverina Water

County Council

(RWCC)

SW205

Sample ID:

0906_0S003_170620

The sample was collected from the Murrumbidgee River at the

RWCC surface water intake at 91 Hammond Avenue. Sample

collected using a PVC bucket.

20 June 2017

MW211

Sample ID:

0906_EWB1_170620

Sample collected from a tap at the RWCC East Wagga Borefield

Bore 1.

20 June 2017

MW212

Sample ID:

0906_EWB2_170620


Bore 2.

20 June 2017

MW213

Sample ID:

0906_EWB3_170620


Bore 3

20 June 2017

POT200

Sample ID:

0906_0S004_170620

Sample collected from a tap at the RWCC sampling point on

Elizabeth Avenue. Water at this point is potable water supplied from

the RWCC Willans Hill reservoir and can include treated water from

the East Wagga and West Wagga Borefields.

20 June 2017

POT100

Sample ID:

0906_DW001_170620

Sample collected from the cold water kitchen tap in the Base medical

centre. This water is supplied from RWCC.

20 June 2017

Gumly Gumly

Private

Irrigation

District

(GGPID)

MW210

Sample ID:

0906_0S002_170620

The sample was collected from a tap at the groundwater bore used

by GGPID.

20 June 2017

Base irrigation

system

MW214

Sample ID:

0906_GW047279_170620

Sample collected from a sampling tap on RAAF Base Wagga Bore 5.

This is the only well that currently supplies irrigation water to the

Base.

20 June 2017

MW215

Sample ID:

0906_GW047281_170620

The sample was collected using a bailer from RAAF Base Wagga

observation well 5. The observation well was installed to monitor

water level drawdown and is located close to Bore 5.

20 June 2017

MW216

Sample ID:

0906_GW030714_170620

The sample was collected using a bailer from RAAF Base Wagga

observation well 4. The observation well was installed to monitor

water level drawdown and is located close to Bore 4.

20 June 2017

OTH201

Sample ID:

0906_IW001_170620

The sample was collected from a sampling tap at Tower 5 on the

Base. Water from Bore 5 is pumped to Tower 5 from where it is

distributed to the Base irrigation network.

20 June 2017


IA147400-003-N-RPT-005 54


Primary Sample ID

Description Sample

date

Surface water

samples

SW206

Sample ID:

0906_SW001_170620

& 0906_SW001_07072017

Sample was collected from the discharge of the stormwater pipe

draining from RAAF Base Wagga to the canal near Elizabeth Ave.

The sample was collected directly into lab supplied container using a

telescopic sampling pole.

20 June 2017

and

7 July 2017

SW207

Sample ID:

0906_SW002_170620

A sample was collected from Kyeamba Creek under the Sturt

Highway bridge. The sample was collected directly into the lab

supplied container.

20 June 2017

Murray Cod

Hatchery

OTH200

Sample ID:

0906_0S001_170620

The sample was collected from the outlet of a pipe used to fill pod A2.

The pipe is connected to the main groundwater bore at the north

western corner of the property (GW401188). Sample was collected

immediately upon opening the outlet valve. The sampling point is

located approximately 70 m from the bore.

20 June 2017

OTH200

Sample ID:

0906_GW205A_D_07072017

Same location as above. Water was running for approximately 1

minute before the sample was collected.

7 July 2017

OTH200

Sample ID:

0906_GW205B_D_07072017

Same location as above. Water was running for approximately 5

minutes before the sample was collected.

7 July 2017

MW200

Sample ID:

0906_GW200_D_07072017

Sample collected from the pipe fitting connecting to the main in-use

deep groundwater bore in the north west of the property

(GW401188). Water was running for approximately 5 minutes before

sample was collected. The sampling point is located approximately

0.5 metres from the bore.

7 July 2017

MW201

Sample ID:

0906_GW201_S_07072017

Sample collected from disused shallow groundwater bore

(GW402595). The sample was collected from the bore using a

disposable bailer.

7 July 2017

MW202

Sample ID:

0906_GW202_D_07072017

Sample collected from end of pipe near concrete tanks south of the

hatchery building. Pipe is connected to the disused deep groundwater

well located under the hatchery building (GW037091). The sampling

point is located approximately 20 m from the bore.

7 July 2017

MW203

Sample ID:

0906_GW203_D_07072017

Sample collected from disused deep groundwater bore located near

western door of the hatchery building (no bore ID). The sample was

collected from the bore using a disposable bailer.

7 July 2017

MW204

Sample ID:

0906_GW204_D_07072017

Sample collected from groundwater bore in southern area of the

property (GW401651). The sample was collected from the bore using

a disposable bailer.

7 July 2017

SW200

Sample ID:

0906_SW200_07072017

Surface water sample from pond in south west corner of property. 7 July 2017

SW201

Sample ID:

0906_SW201_07072017

Surface water sample from pond immediately west of MW204. 7 July 2017

SW202

Sample ID:

0906_SW202_07072017

Surface water sample from pond A4 7 July 2017


IA147400-003-N-RPT-005 55


Primary Sample ID

Description Sample

date

SW203

Sample ID:

0906_SW203_07072017

Surface water sample from pond A1 7 July 2017

The sampling locations are shown on Figures 5a, 5b, 5c and 5d in Appendix A.

All samples were analysed for an extended PFAS suite by ALS Environmental, a laboratory accredited by the

National Association of Testing Authorities (NATA) for the analysis performed. The analysis results are

summarised in the relevant tables in Appendix T. Laboratory certificates of analysis are provided in Appendix

U.

7.3.2 Fieldwork methodology

The methodology applied for the collection of the samples is described in Appendix F.

7.3.3 Quality assurance and quality control

In order to assess the useability of the data collected for decision making processes, the data was assessed

against a set of data quality indicators and acceptance criteria as described in Appendix O.

Blind replicate, split and trip blank quality control samples were collected during the preliminary sampling

program. Data validation reports for each batch of samples are presented in Appendix P.

The data collected during the preliminary sampling program were considered to meet the data quality objectives

and can be used for the intended purpose.

7.3.4 Investigation criteria

Analysis results for the samples collected during the preliminary sampling program were compared to a set of

investigation criteria based on published Tier 1 screening values. These investigation criteria are presented in

Section 11.

7.3.5 Findings

7.3.5.1 Drinking water supplies

The samples collected from the RWCC supply sources, in the potable water supplied to the Forest Hill area and

in the potable water at the Base had concentrations of PFAS below the laboratory LOR and below the adopted

investigation criteria for drinking water. Similarly, the sample collected from the GGPID bore had PFAS

concentrations below the laboratory LOR and the adopted investigation criteria for drinking water.

7.3.5.2 RAAF Base Irrigation

The reported concentrations of the PFAS compounds analysed were below the LOR in the samples collected

from Bore 5, Bore 4 and the Bore 5 observation well as well as Tower 5 with one exception. The reported

concentration of PFOS in the sample from the Bore 5 observation well was 0.06 µg/L.

There are no Tier 1 screening criteria established by the Commonwealth or NSW EPA for the assessment of

PFAS in water used for irrigation. It is however noted that the reported concentrations of PFOS + PFHxS and

PFOA are below the adopted investigation criteria for drinking water.

GHD (2016) reported a PFOS concentration of 0.04 µg/L at the Bore 5 observation well in May, 2016. The

observation well is located approximately 30 m away from RAAF Base Wagga Bore 5. Observation well 5 has a


IA147400-003-N-RPT-005 56

PVC pipe casing and a screened interval between 20.4 and 47.5 mBGL. While Bore 5 has a stainless steel

casing and has screened intervals between 43.6 and 52.7 metres below ground surface.

The construction details for both wells indicate a water bearing zone from approximately 20.4 metres to the

termination depth on granite and therefore, while the screened sections for both wells differ, the screens appear

to be located in the same water bearing layer.

7.3.5.3 Murray Cod Hatchery

Several PFAS compounds were detected at concentrations above the laboratory LOR in all samples collected

from the Murray Cod Hatchery.

There are no Tier 1 screening criteria established by the Commonwealth or NSW EPA for the assessment of

PFAS in water used for aquaculture activities.

7.3.5.4 Surface water samples

PFAS concentrations in the sample collected from Kyeamba Creek at Sturt Highway (SW207) were below the

laboratory LOR. This location is considered upgradient (background) from the point on Kyeamba Creek where

stormwater flow from the Base may discharge.

Several PFAS compounds were detected above the laboratory LOR in the surface water samples collected from

the canal near Elizabeth Avenue (SW206). Concentrations of PFOS and PFHxS did not vary significantly

between the sampling events. The concentration of PFOS exceeded the screening criterion for protection of

direct toxicity to aquatic ecology (95% species protection).


IA147400-003-N-RPT-005 57

8. Preliminary conceptual site model

8.1 Summary of key information

The following points summarise key findings from the review of existing information, site observations and

preliminary sampling program:

The Base is situated within the Murrumbidgee Valley and therefore the local topography is relatively flat

and has acted as the floodplain for the Murrumbidgee River. The Murrumbidgee River is located

approximately 4km north of the Base and flows from east to west. There are a number of watercourses

around the Base as follows:

- Kyeamba Creek – Tributary of the Murrumbidgee River flows northwards to the east of the Base

- Gregadoo Creek – Ephemeral water course to the west of the Base

- Marshalls Creek – Tributary of the Murrumbidgee River down gradient and to the west of the Base

Stormwater run-off from the northern areas of the Base is collected via a system of stormwater drains,

which discharge from the north-west of the Base into the Gumly Gumly Wetland. Stormwater run-off from

the southern areas of the Base drains to on-Base and off-Base farm dams. During extended periods of

high rainfall, run-off appears to overflow from these farm dams and into Gregadoo Creek to the west of the

Base or Kyeamba Creek in the east of the Base. The inferred drainage paths are presented on Figure 3.

The geology underlying the Base consists of alluvial deposits, described locally as comprising two layers:

the Cowra Formation and the underlying Lachlan Formation. The hydraulic properties of these units are

expected to result in a reasonable degree of vertical hydraulic connectivity, particularly in areas close to the

river where the alluvium is comprised of coarser grained sediments Furthermore, it is noted that there are a

large number of registered bores throughout the region which may act as pathways for vertical

groundwater movement. The Cowra Formation consists of up to 20 m of clays and silts in the region

around the Base. Investigations by Golder (2012a) identified that a large proportion of the Base consisted

of surficial clay soils in the upper 3 metres. Based on typical hydraulic properties of clay, this is considered

to substantially attenuate vertical hydraulic connectivity between the ground surface and the underlying

permeable horizons.

Regional groundwater is expected to flow towards the Murrumbidgee River. In the vicinity of the Base,

groundwater gradients indicate flow towards the north west. As noted above, there is a large number of

registered groundwater bores in the region surrounding the Base including in the areas north and north

west of the Base which are considered to be hydraulically down gradient.

RWCC supplies potable water to the Base and throughout Wagga Wagga including Forest Hill and the

surrounding areas. The primary source of water supply for RWCC is from borefields located in the north,

east and west of Wagga Wagga. In addition, approximately 20% of total water is sourced from the

Murrumbidgee River on an annual basis. The Murrumbidgee River intake is located approximately 8km

north west of the Base. The East Wagga Wagga borefield consists of two bores located along Kooringal

Road between Hammond Avenue and the Murrumbidgee River and a third bore located at the northern

end of Gillard Road. These bores are all located approximately 7km (downgradient) from the Base.

The GGPID supplies approximately 60 users with water for domestic and irrigation purposes. The GGPID

bore is located approximately 4 km north west (downgradient) of the Base.

There are five off-Site bores owned by Defence that were historically used to supply water to the Base.

One of the bores (Bore 5) is still used to supply water for irrigation purposes only.

Identified historical activities associated with the use of AFFF at the base are primarily related to firefighting

services, including training. Several key areas of interest in regards to documented AFFF use at the Base

have been identified, including: RMV0093 (Fire Training Area), RMV0097 (Fire Station), NSW1105 (Former

Bitumen Plant and Neptune Plane Fire Training Area) and RMV0098 (Fire Extinguisher Concrete Pad).

3M Lightwater was used as the AFFF product at the Base from approximately 1970 to approximately 2005

when it was replaced with Ansulite.


IA147400-003-N-RPT-005 58

Several off-Base locations were identified as potential sources of PFAS contamination, including the Forest

Hill Rural Fire Service (RFS), Forest Hill Sewage Treatment Plant (STP) which receives sewage from the

Base, former Council landfill at Forest Hill and the Kooringal STP.

Previous investigations identified PFAS impacted soils and/or groundwater at the Base, including

concentrations of PFOS and/ or PFOA above the level of detection in soils and groundwater at RMV0098

(Fire Extinguisher Concrete Pad) and concentrations of PFOS of (0.04 ug/L) in off-Base groundwater well

GW047281, located approximately 1 km north of the Base. In addition, two surface water samples

(WAG_SW001 and WAG_SW002) located on the western boundary of the Base, returned concentrations

of PFOS above the laboratory Limits of Reporting (LOR).

Preliminary sampling undertaken by Jacobs in June and July, 2017 found that PFAS concentrations were

below the laboratory LOR in samples collected from the RWCC and GGPID water supplies. Samples from

the bore used to supply irrigation water to the Base (Bore 5) as well as the irrigation water storage tower on

Base had PFAS concentrations below the laboratory LOR. However previous sampling by GHD and

sampling conducted by Jacobs identified concentrations of PFOS above the laboratory LOR in a monitoring

well near Bore 5.

The preliminary sampling undertaken by Jacobs identified PFAS in water samples collected from

groundwater wells and aquaculture ponds at the Murray Cod Hatchery.

PFAS was also detected in a surface water sample from a channel that receives surface water from the

Base and part of Forest Hill. Water from the channel then discharges to Gumly Gumly Wetland.

8.2 Potential PFAS Sources

The following on-Base and off-Base potential sources of PFAS were identified based on the review of existing

information.

8.2.1 On-Base

A summary of potential on-Base sources of PFAS is provided in Table 8.1. The approximate locations of the

sources are presented in Figures 6a and 6b.

Table 8.1 : Summary of potential on-Base sources of PFAS

Potential PFAS Contamination Source

Description

Potential Primary Sources

RMV0093 - Fire Training

Area

Historical fire training area located adjacent to the eastern end of the runway.

RMV0097 - Fire Station Current fire station located on the southern side of Barker Street. Includes a designated storage area for

AFFF.

Fire Extinguisher Concrete

Pad (RMV0098) and

Former Fire Station

The fire extinguisher concrete pad is located on the northern side of Barker Street. This area and the area

further east was the location of the former fire station which was demolished sometime between 1990 and

1995.

RMV0179 - Abandoned

Sewage Services

It is understood the former sewage treatment plant was operational until 1993 and was located near the

north western corner of the Base. It consisted of a primary screening facility and two secondary treatment

circular trickling filter tanks, located on the western boundary in the vicinity of the current residential

precinct.

Building 83 - Vehicle

Maintenance

Maintenance activities were reportedly undertaken by the Defence MTG in Building 83, including the

potential maintenance of fire fighting vehicles.


IA147400-003-N-RPT-005 59


Description

RMV0092 - Former Land

Filling Area 1

This former land filling area is located in the south western corner of the Base and covers an area of

approximately 10 hectares. The area has previously been the location of significant unregulated filling and

has also been utilised as a stockpiling area for soils sourced from various areas across the Base, including

earthworks completed at NSW1105 (Former Bitumen Plant and Neptune Plane Fire Training Area).

Therefore, the potential for this area to be a potential source of PFAS contamination could not be

discounted.


Filling Area 2

This former landfilling area is located north of the current airport taxi ways and east of the Base Hanger

Precinct. The area is located adjacent to RMV0093 fire training area and is reported to contain perched

groundwater as a result of infiltration within the unconsolidated fill material. Further investigation is required

to determine potential impacts from the nearby fire training area on perched groundwater.

NSW1105 - Former

Bitumen Plant and Neptune

Plane Fire Training Area.

A portion of the area was reported to have been used for fire training, where Diesel, petrol and kerosene

were poured onto an old Neptune aircraft and set alight.

RMV0123 - Former toxic

Chemical Store

Limited information was available to discount this area as a potential source PFAS contamination.

Aircraft parking area South

of Building 88

The apron south of building 88 was noted in a hand mark-up site plan (Defence, n.d.) received from

Defence as an area where AFFF was discharged. Jacobs has requested further information.

Taxiway A - Fire

Extinguisher training

During a site inspection completed by Jacobs on 19 June 2017, WWCDA personnel advised that the Base

ARFF personnel and WWCDA conducted joint fire training every two years involving responding to a mock

airside incident and using hand held extinguishers to put out a fire. One of the training exercise occurred

near Taxiway A close to an earth grounding point.

Former Apprentices Club A controlled burn was used to demolish this building in 1985. AFFF may have been used to extinguish the

fire.

Historical residential

building fire

A fire was reported to have occurred in a residential building on Gray Street. It is not clear if it was the

building on the northern or southern side of the street. AFFF may have been used to extinguish the fire.

Potential Secondary Sources

Irrigation areas including

playing fields and golf

course

Potentially impacted groundwater is used at the Base to irrigate several recreational playing fields and golf

course.

Stormwater and sewer

infrastructure

Contaminated soil, sediment and water within stormwater and sewer infrastructure (including drainage

swales) has the potential to act as secondary sources for ongoing contamination of surface water due to

adsorption of PFAS into concrete infrastructure and leaching to groundwater at the Base.

8.2.2 Off-Base

A summary of potential off-Base sources of PFAS is provided in Table 8.2. The approximate locations of the

sources are presented in Figures 6a and 6b.

Table 8.2 : Summary of potential off-Base sources of PFAS


Description

Potential Primary Sources

Forest Hill Rural Fire Service Located in the Forest Hill residential area to north west of the Base. There is a potential for

AFFF to have used and stored by the RFS at the Forest Hill station.

Forest Hill STP

Operated by Council the STP is located approximately 1.2km north of the Base. The STP treats

and discharges (as irrigation water) waste water from the Base and surrounding Forest Hill

residential area. Biosolids from the plant are spread on land around the STP.


IA147400-003-N-RPT-005 60


Description

Kooringal STP

Operated by Council the STP is located approximately 6 km west of the Base. Treated effluent

from the STP discharges to either the Murrumbidgee River via Marshalls Creek or into the

network of effluent reuse/irrigation projects administered by Council. Waste sludge is digested,

held in lagoons and then removed to landfill.

Former Council landfill at Forest Hill

Council formerly operated a landfill south of the STP at Forest Hill from 1975 to approximately

2000. The landfill received municipal, commercial, industrial and liquid waste. Waste was

initially buried in unlined trenches. Improvements were made in the 1980s and 1990s including

the construction of lined landfill cells.

Potential Secondary Sources

Irrigation areas adjacent to the Forest

Hill STP

Treated waste water has been historically utilised as irrigation water for two spray pivot irrigator

areas on various crops and at the South Tahara Plantation located adjacent to the STP.

Gumly Gumly Wetland PFAS impacted surface water and sediment may accumulate in Gumly Gumly Wetland and

leach to groundwater.

8.3 Transportation mechanisms

Transportation mechanisms are considered to include:

Direct release to soil

Leaching of contaminants to perched groundwater, groundwater in the Cowra Formation and groundwater

in the Lachlan Formation

Migration of contaminants in the Cowra Formation and the Lachlan Formation. Regional groundwater

migration is towards the Murrumbidgee River. There appears to be connections between groundwater in

the Cowra and Lachlan Formations.

Stormwater transportation of soil / sediment particles

Surface run-off and stormwater run-off of PFAS impacted water

Spray drift of impacted water during fire fighting activities or irrigation

Transport via stormwater or sewer infrastructure

Extraction of impacted groundwater or surface water for irrigation and water supply

Bioaccumulation and biomagnification of PFAS in the food chain

8.4 Exposure pathways

Exposure pathways are considered to include:

Human exposure through incidental ingestion / inhalation of soils or soil derived dust

Human exposure through direct contact with impacted surface water or groundwater

Human exposure through ingestion of impacted groundwater or surface water

Human exposure through ingestion of impacted edible products

Human exposure through recreational use of water bodies

Terrestrial ecology exposure (including livestock) through direct contact with soil or water

Aquatic ecology exposure through direct contact with sediment or water

Further detail is provided in relation to completeness of exposure pathways in Section 13.3, Table 13.2.


IA147400-003-N-RPT-005 61

8.5 Receptors

Potential on-Base receptors were identified as:

Human

Construction and maintenance workers at the Base

Adults living or working on Base (no children are present for extended periods)

Recreational adult users of Base open space and sporting facilities (i.e. golf course and sporting fields)

Ecological

Terrestrial flora and fauna

Aquatic organisms in surface water bodies (limited to drainage channel and dam in airport area)

Potential off-Base receptors were identified as:

Human

Residents / workers residing on adjacent properties;

Recreational users of Kyeamba Creek, Gregadoo Creek, Gumly Gumly Wetland or the Murrumbidgee river

Human consumption of fish and shell fish from the Murray Cod Hatchery, Kyeamba Creek, Gregadoo

Creek, farm dams or the Murrumbidgee River

Human consumers of extracted groundwater

Human consumers of abstracted surface water

Human consumers of impacted produce or biota (e.g. eggs, livestock, produce from vegetable gardens,

fish and yabbies)

Ecological

Terrestrial flora and fauna on adjacent land

GDEs, including aquatic and benthic flora and fauna inhabiting Kyeamba Creek, Gregadoo Creek or Gumly

Gumly Wetland.

Potential source to receptor pathway linkages are presented graphically in Figures 7a and 7b.


IA147400-003-N-RPT-005 62

9. Investigation data quality objectives

The Data Quality Objectives (DQOs) process is used to define the type, quantity and quality of data needed to

support decisions relating to the environmental condition of a site (NEPC, 2013). Schedule B2 of the NEPM

outlines the seven step DQO process developed by the US EPA as one example of a suitable systematic

planning approach for site investigations.

The seven step DQO process is as follows:

Step 1: State the problem;

Step 2: Identify the decision or goal of the investigation;

Step 3: Identify the information inputs;

Step 4: Define the investigation boundaries;

Step 5: Develop the analytical approach or decision rule;

Step 6: Specify the performance or acceptance criteria; and

Step 7: Optimise the design for obtaining the data.

The DQO process has been applied as described below, to ensure that data collection activities were

appropriate and achieved the stated objectives.

9.1.1 Step 1: State the problem

Key aspects of the problem are presented in Table 9.1 below.

Table 9.1 : Key aspects of the problem

Aspect Description

Project drivers: Defence has used Aqueous Film Forming Foam (AFFF) products to suppress liquid fuel fires, in firefighting

training operations at the Base. From 1970 to approximately 2005 the AFFF used by Defence contained

PFAS. Concentrations of PFAS including PFOS; PFOA and PFHxS have been identified in soil, surface water

and/or groundwater at the Base or in the surrounding areas. This contamination may be impacting on human

health or ecological receptors.

Objectives: The key objectives of the Project are:

To characterise the extent of PFAS contamination on and surrounding RAAF Base Wagga

To identify the potential human and ecological receptors for the contamination

To assess the risks posed by the contamination to these potential receptors

To identify management actions to respond to the risks where necessary

Key issues: Historical activities may have caused PFAS contamination of soil and sub-surface structures at the Base.

This contamination may be impacting on-Base receptors. The contamination may also be migrating via

surface water, sewer infrastructure and groundwater to off-Base receptors.

There are various beneficial uses of surface water and groundwater in the areas surrounding the Base

including use of groundwater for water supply, irrigation, aquaculture and stock watering.

Data is required to further characterise the soil, sediment, surface water and groundwater conditions to

enable an assessment of the risks posed by PFAS impacts to human health and ecological receptors.

Biota sampling will also be required to assess the potential for risks associated with human consumption

of food and to assess potential risks to ecology.

Where unacceptable risks are identified, appropriate management measures will be required to mitigate

these risks. Therefore, data collected as part of the DSI may also be used to assess and design potential

risk mitigation strategies.

Conceptual model A preliminary conceptual model for the Site is summarised in Section 8.


IA147400-003-N-RPT-005 63

Aspect Description

Community and

stakeholder

engagement

PFAS contamination has the potential to impact off-Base receptors and so there is the potential for significant

community interest. Local, state and commonwealth agencies will also be part of the whole of government

management of the issues. A community engagement plan has been developed and will be implemented

throughout the Project. A Project Control Group has also been established to ensure government

stakeholders are kept informed of the Project progress and have opportunities to provide input.

9.1.2 Step 2: Identification of the decision or goal of the investigation

The Project is focussed on the assessment of PFAS contamination associated with historical operations by

Defence at the Base and the potential risks presented by this contamination to on-Base and Off-Base human

health and ecological receptors. The decisions statements that needed to be answered from the DSI are listed

in Table 9.2.

Table 9.2 : DSI decision statements

Aspect Description

PFAS sources and

transport pathways

What is the nature and extent of PFAS contamination on the Base?

What are the transport mechanisms and destinations of the PFAS contamination?

What is the resulting nature and extent of PFAS contamination outside the Base?

Receptors and risk What human health and ecological receptors are exposed to the PFAS contamination?

Are off-Base sources of PFAS also contributing to exposures for these receptors?

Is there the potential for unacceptable risks to these receptors posed by the exposure to PFAS

contamination?

Could contaminant migration over time lead to unacceptable risks in the future?

Risk mitigation What are the potential options for mitigating unacceptable risks?

Uncertainties Are there material uncertainties remaining after the DSI?

9.1.3 Step 3: Identify the information inputs

The primary inputs required to respond to the decision statements in Step 2 are presented in Table 9.3.

Table 9.3 : Information inputs

Aspect Description

Site conditions Information obtained as part of the Preliminary CSM including PFAS concentration data from previous

investigations

New information on site conditions and risk factors collected during the DSI

PFAS concentration

data

Collection of representative soil, sediment, surface water, groundwater and biota (e.g. fish and

vegetation) samples, and laboratory analysis of these samples for PFAS with detection limits

appropriate to the adopted investigation criteria

Collection of data on the leachability of PFAS from soil in areas of soil contamination

Assessment of the suitability of the data through application of Data Quality Indicators (DQIs)

Geological and

hydrogeological data

Logging of soil composition and conditions

Collection of data on hydrogeological conditions

Investigation criteria Assessment of the PFAS concentration data against the adopted investigation criteria (see Section 10)

Risk assessment Findings of the Human Health and / or Ecological Risk Assessment/s


IA147400-003-N-RPT-005 64

9.1.4 Step 4: Define the investigation boundaries

The investigation boundaries are presented in Table 9.4.

Table 9.4 : Investigation boundaries

Aspect Description

Lateral boundaries The lateral boundaries of the study area are shown in Figure 8. This area is approximately 5,700 hectares.

It is referred to as the Study Area and has been defined with consideration of Defence guidance on the

identification of study areas (Defence, 2017b) as well as the following factors:

The direction of regional groundwater gradient is understood to be towards the Murrumbidgee River, in

a north westerly direction from the Base and therefore the Study Area is generally skewed towards this

direction.

There is the potential for PFAS impacts in the Murrumbidgee River from groundwater inflow or due to

PFAS impacted surface water entering the river from Kyeamba Creek. Based on information reviewed

to date, the potential for PFAS impacts in groundwater north of the Murrumbidgee River is considered

unlikely and therefore the northern boundary of the Study Area is set at the northern bank of the

Murrumbidgee River (i.e. the Study Area includes the Murrumbidgee River).

Surface water drainage from the portion of the Base north of the Airport primarily discharges through

formalised stormwater infrastructure to the Council stormwater network at a point in the north western

area of the Base. This Council network discharges to Gumly Gumly Wetland. Maps and aerial images

indicate the potential for water from Gumly Gumly Wetland to flow to Marshalls Creek during extended

periods of high rainfall. Marshalls Creek then discharges to the Murrumbidgee River. Therefore the

Study Area includes Gumly Gumly Wetland and extends along Marshalls Creek.

Drainage from the southern area of the Base appears to be via overland flow towards the west into

ephemeral drainage lines which may discharge to Gregadoo Creek. There may also be ephemeral

drainage from Gregadoo Creek to Marshalls Creek. There also appears to be overland flow paths from

the eastern area of the Base to ephemeral streams which discharge to Kyeamba Creek. Therefore the

western and eastern boundaries of the Study Area have been set to consider these potential drainage

flows.

There is an area of land on the eastern side of Kyeamba Creek near the Murrumbidgee River which is

irrigated with effluent from the Forest Hill Sewage Treatment Plant (360 degree pivot). This area is

included in the Study Area.

The southern boundary of the Study Area is aligned with the southern boundary of the Base as there

does not appear to be any surface water flow from the Base in this direction and the regional

groundwater gradient is understood to be towards the north west. It is noted that the most southern

potential PFAS source area identified is the Former Toxic Chemical Store (RMV0123) located

approximately 500 m north of the southern boundary of the Study Area.

Vertical boundaries The vertical boundaries of the Study Area are from the ground surface to the base of the Lachlan

formation (surface of the Wantabadgery granite and surrounding sedimentary sequence). Construction

logs for registered bores in the area around the Base reviewed by Jacobs as part of the Preliminary

CSM indicate that groundwater extraction in the area focusses on the alluvial aquifer.

Temporal boundaries The DSI was undertaken from approximately September 2017 to January 2018. Historical records

indicate that rainfall is spread evenly across the year, with slightly increased rainfall in the May to

October months. Therefore groundwater levels in the alluvial aquifer are not expected to vary to such

an extent that PFAS impacts are significantly influenced. Surface water conditions in the area may vary

more significantly due to rainfall and flow controls in the Murrumbidgee River. A review of both surface

water and groundwater data collected during the DSI field program as well as associated rainfall

conditions and surface water flows during the sampling events has been performed and is discussed in

Section 14.

Constraints Sampling locations may be constrained by the presence of underground services and / or access

provisions for sampling equipment.

There are constraints associated with sampling activities on the airfield due to aircraft safety.

The collection of samples at off-Base locations will require access permission from the property owner.


IA147400-003-N-RPT-005 65

9.1.5 Step 5: Develop the analytical approach or decision rule

The purpose of this step was to define the parameters of interest, specify action levels and combine the outputs

of the previous DQO steps to develop a series of options if certain trigger events occur.

The key decision rules for the DSI were:

1) Have the analytical data collected as part of the DSI met the DQI (see below)? If yes then the data can be

used to answer the decision rule below and the decision statements developed in Step 2. If no then an

assessment of the need to collect additional data will be required.

2) Do PFAS concentrations exceed the investigation criteria defined in Section 10? If no then the

contamination does not pose an unacceptable risk. Where results exceed the adopted investigation criteria,

this may not necessarily indicate an unacceptable level of risk. Further risk assessment, and potentially

additional investigations, will be required to determine the potential for unacceptable impacts.

In order to assess the useability of the data for making decisions, the data has been assessed against a set of

DQI, developed based on the following parameters:

Precision: A quantitative measure of the variability (or reproducibility) of data;

Accuracy: A quantitative measure of the closeness of reported data to the “true” value;

Representativeness: The confidence (expressed qualitatively) that data are representative of each media;

Completeness: A measure of the amount of useable data from a data collection activity; and

Comparability: The confidence (expressed qualitatively) that data may be considered to be equivalent for

each sampling and analytical event.

The quality assurance and quality control measures applied to assess data quality in relation to the DQI as well

as the acceptance criteria set for the project are outlined in Appendix O.

9.1.6 Step 6: Specify performance or acceptance limits

This step involves specifying acceptable limits on decision errors. Decision errors are incorrect decisions

caused by using data that are not representative of site conditions due to sampling or analytical error (DEC,

2006).

There are two key types of decision errors that can occur for the Project:

a) Deciding that the risks posed by PFAS exposure for a particular receptor are acceptable when these

risks actually are not acceptable. The consequence of this error may be unacceptable impacts to

human health or the receiving environment; or

b) Deciding that the risks posed by PFAS exposure for a particular receptor are unacceptable when the

risks actually are acceptable. The consequence of this error is that management actions will be

undertaken to reduce the risks are not necessary.

The more severe consequences are with decision error (a) since the risk of jeopardising human health and/or

the environment outweighs the consequences of undertaking management actions that are not necessary.

Developing and assessing acceptance criteria for decisions based on confidence levels would require collection

of a statistically significant set of samples for each human or ecological exposure scenario. This is not feasible

given the large number of potential scenarios and the intended use of targeted sampling. Therefore, a

conservative approach has been adopted to minimise the likelihood that decision error (a) occurs. This involved

the collection of samples in areas considered likely to have the highest concentrations of contaminants based

on site history and site setting information. The maximum concentration of the PFAS contaminant of concern for

each exposure scenario has also been compared to the investigation criteria to determine the potential for risk

and if further sampling is required.


IA147400-003-N-RPT-005 66

9.1.7 Step 7: Develop the plan for obtaining data

A sampling and analysis plan was developed and is discussed in Section 10. The plan was developed to meet

the data quality objectives and was optimised based on the findings of the Preliminary CSM.


IA147400-003-N-RPT-005 67

10. Investigation approach and methodology

10.1 Project Stages

The project has a number of distinct phases that combine to contribute to a holistic understanding of the

impacts caused by contamination at a particular site, and the need for management, including:

The NEPM investigation process, developing a CSM, which is then used to prepare an SAQP and

undertake the DSI. Investigation also takes into account the 'outside in' approach recommended in the

NSW EPA Guidance Document - Designing Sampling Programs for Sites Potentially Contaminated by

PFAS. A key element of the NSW guidance is consideration of PFAS characteristics that are different to

common contaminants that affect the design of a site investigation, these include persistence, high

solubility in water, bioaccumulation potential and surfactant characteristics. These characteristics mean

they may disperse widely in the environment due to stormwater runoff and leaching into groundwater. This

means that a more traditional approach to characterisation of PFAS source areas through stepped out

sampling is reversed to one that takes an ‘outside in’ approach accounting for these differing PFAS

characteristics. This approach does not ignore investigation of potential source zones, however it places

greater emphasis on understanding risk to the broader area through transport away from identified

sources.

Further assessing risk through the HHERA (including additional data collection to help inform elements of

the HHERA).

Identifying the need for management or remediation of PFAS contamination based on holistic consideration

of the updated CSM, completeness of source-pathway-receptor linkages and associated risk.

Where the above process identifies the need for management or remedial measures, ongoing monitoring

may be required to ensure that those identified remain effective and do not result in future impacts to

human health or the environment.

Therefore, the findings of the DSI do not represent a definitive statement of the potential risks associated with

PFAS in the Study Area. It should instead be seen as a step in border NEPM process that is used to assess risk

and identify appropriate management measures.

10.2 Sampling plan

A sampling plan was developed based on the DQO presented in Section 9 and is summarised in the following

categories:

On-Base source characterisation. Sampling of soil and perched groundwater (if present) to characterise

on-Base sources. The sampling densities and depths presented in the plan aimed to confirm the

significance of the source and provide preliminary information to enable options assessment of source

management strategies. It was noted that additional sampling may be required to provide sufficient data for

design of remediation.

Investigation of irrigation and biosolids application areas. Sampling of soil in on-Base irrigation areas

and sampling soil and biota (vegetation) in off-Base irrigation areas was proposed. These areas were

considered to be a lower risk for significant PFAS contamination. In the Forest Hill STP irrigation areas

potential impacts are due to use of potentially impacted treated effluent and the application of biosolids to

land in the area around the STP (not due to direct application of AFFF). For the Base irrigation areas,

preliminary sampling has indicated that bore water is currently not impacted or has low level impacts.

Therefore, only a limited number of samples were proposed in these areas.

Investigation of overland drainage pathways. Sampling of surface water, sediment and / or soil was

proposed in overland drainage pathways including Gregadoo Creek, Gumly Gumly Wetland, Marshalls

Creek and Kyeamba Creek. Sampling was proposed for the full length of these pathways to the

Murrumbidgee River. Sampling of surface water and sediment was also proposed at four locations in the

Murrumbidgee River. Sampling of biota (vegetation) was proposed in ephemeral drainage areas where

livestock may graze. It is noted that the DSI sampling plan did not include sampling of aquatic biota with

the exception of the Murray Cod Hatchery. Sampling of aquatic biota may be required in farm dams,


IA147400-003-N-RPT-005 68

Gregadoo Creek, Marshalls Creek, Kyeamba Creek and the Murrumbidgee River in order to assess

potential human health risks due to consumption of fish and other aquatic biota as well as to assess

potential ecological risks due to biomagnification. Initial collection of surface water and sediment samples

along these drainage paths was to be carried out in order to assist in understanding the potential extent of

PFAS contamination and to enable an appropriate biota sampling plan to be developed.

Investigation of groundwater migration. Sampling of existing and new groundwater wells to understand

groundwater migration pathways. The sampling plan included perched groundwater (which from previous

investigations has been identified in limited locations in the upper weathered zone in the clay horizon),

sampling from the Cowra formation and sampling from the Lachlan formation. Use of existing wells was

prioritised in off-Base locations in order to minimise disturbance to third party properties and improve

spatial coverage. It was noted that additional sampling from other existing wells or new wells may be

required following a review of data collected during the program. Hydrogeological testing was also

proposed in order to understand aquifer hydraulic conductivity and to enable modelling of contaminant

transport if required. This could assist in responding to the decision statement on potential future risks

included in the DQOs.

Point of use sampling. Sampling of surface water, sediment and groundwater to assess impacts at

locations where potentially impacted surface water or groundwater is in use. This information will also be

used to understand overall groundwater impacts and migration conditions.

Sampling of groundwater at the former Council landfill at Forest Hill. There are a number of existing

groundwater monitoring wells at the former Council landfill at Forest Hill and therefore sampling of several

of these wells was proposed in order to assess whether the landfill is an off-Base source of PFAS.

It should be noted that access to all proposed off-site locations was not undertaken until the landowner had

been identified and an access agreement arranged. Analysis results provided in this report are presented in

accordance with the access agreement.

Full details of the planned sampling are provided in Appendix E.

10.3 Analysis plan

Samples submitted for laboratory analysis were all analysed for an extended PFAS suite. Analysis of other

parameters such as % clay, Total Organic Carbon (TOC), cation exchange capacity (CEC) and major ions for

selected samples was also undertaken to assist in understanding conditions potentially affecting PFAS

transport.

Full details of the analysis plan are presented in Appendix E.

10.4 Summary of investigation works completed

The DSI fieldwork program was carried out between June 2017 and February 2018. A summary of the works

completed is presented in Table 10.1.


IA147400-003-N-RPT-005 69

Table 10.1 : Summary of samples by location and sample type

Target area Number of locations | number of samples

Soil & co-located biota (veg) Co-located surface water &

sediment

Groundwater

Total

locations

Soil

samples

Biota

(veg)

samples

Total

locations

Sediment

samples

Surface

water

samples

Total

locations

Samples

Primary source areas

(on-base)

106 267 - - - - 211 14

Irrigation and biosolid

application areas (on

and off-base)

24 24 7 - - - - -

Secondary source

areas (off-base)

20 20 - - - - 6 6

Overla

nd d

rain

age p

ath

ways

On-base

drainage

25 25 - 6 4 3 - -

Drainage to

Gumly Gumly

wetlands

20 27 5 14 11 13 - -

Drainage to

Gregadoo Creek

2 2 4 12 12 12 - -

Drainage to and

via Marshalls

Creek

3 3 3 7 7 7 - -

Drainage to and

via Kyeamba

Creek

5 5 3

12 11 11 - -

Murrumbidgee

River

- - - 9 6 10 - -

Other 10 10 - 30 20 18 - -

Extractive groundwater

users & regional

monitoring bores

- - - - - - 30 40

New deep groundwater

wells

- - - - - - 141 15

Total 215 383 10 90 71 74 71 75

1 Refers to number of wells installed during the DSI. Seven perched wells and six Cowra Formation wells did not produce measurable water

during the DSI period therefore were not sampled.

It is noted that there were a number of locations where co-located surface water and sediment sampling was

planned. However, in some cases, there was no surface water present and only a sediment sample was

collected and in other cases, while it was possible to collect a surface water sample, collection of a sediment

sample was not possible due to safety or access issues.

10.5 Fieldwork methodology and photos

The fieldwork methodology is set out in Appendix F. Selected photos from the field program are presented in

Appendix G.


IA147400-003-N-RPT-005 70

10.6 Variations from the sampling and analysis plan

The following minor variations from the SAQP occurred during the DSI:

1) The locations for the installation of the paired well set in the Gumly Gumly Wetland were shifted towards

the north as the original planned locations were not accessible with a drill rig due to soft ground. The area

to the north was selected as it was in flood prone land unlikely to be subject to future development and

therefore enabling use of the monitoring wells in the long term. The location is also inferred to be

hydraulically downgradient of the wetland.

2) There was no surface water present at a few locations where co-located surface water and sediment

samples were planned. Therefore, sediment samples only were collected at these locations.

3) A number of registered wells nominated for sampling were either not accessible or dry. Each well

investigated and the reason a sample could not be collected is presented in Figure 9 in Appendix A and in

the tables provided in Appendix J.

4) Samples of effluent from two locations in the Forest Hill STP were collected to better understand PFAS

inputs to the plant. The results of sampling at the Forest Hill STP are discussed in Section 12.3.3.1.

5) It was not possible to collect all planned aquatic biota (fish) samples at the Murray Cod Hatchery during the

DSI due to the availability of fish. Sampling of biota at the Murray Cod Hatchery will be completed as part

of the Human Health and Ecological Risk Assessment (HHERA) process discussed further in Section 15.

6) Samples of fruit and / or vegetables were not collected from the property adjacent to Murray Cod Hatchery

as no fruit or vegetables were being grown at the time of Jacobs visit. Soil, sediment and surface water

samples were collected from the property and the need for additional biota sampling will be evaluated as

part of the HHERA process.

7) Additional sediment and surface water samples were collected from the property adjacent to Murray Cod

Hatchery as additional ponds were identified as accessible and potentially in use.

8) An additional 20 shallow soil samples were collected at the Equex sports facility where it was identified that

water from Marshalls Creek is used for irrigation.

Variations were discussed with and approved by Defence and the Site Auditor throughout the investigation

process. It is considered that the variations to the SAQP do not impact the data quality as they capture minor

variation to existing environmental conditions or will be undertaken at a later stage of the project.

Additional sampling was conducted in several areas based on the data reviewed during the DSI. These

variations are described in the following sections.

10.6.1 Additional shallow soil sampling near the north west corner of the Base

Field observations and information supplied by community members indicated the potential for surface water

runoff from the north west corner of the Base to enter the Council land between the Base boundary and

Kurrajong Avenue. A total of nine shallow soil samples were collected in the lowest point in the drainage swales

on Base in this area and additional soil sampling in the Council area was carried out to further evaluate the

soils.

A total of five additional shallow soil samples were collected in the Council land. Three shallow soil samples

were located along the low point axis of potential overland flow. The other two shallow soil samples were

collected close to the rear boundary of private properties adjoining the Council land.

The sampling locations are presented on Figure 28 in Appendix A. The results of this sampling are discussed

on Section 12.3.5.1.1.

10.6.2 Additional groundwater investigations in Gumly Gumly and East Wagga

During the course of the DSI, it was determined that additional sampling of regional groundwater in the Gumly

Gumly and East Wagga area would be useful to further characterise the extent of groundwater impacts. Jacobs


IA147400-003-N-RPT-005 71

visited properties with registered groundwater bores in the area during the DSI. A total of 30 registered

groundwater bores were investigated. Of which, 27 bores were either not located (18 bores), not accessible (3

bores) or dry (6 bores). Groundwater samples were collected at three bores (MW225, MW234 and MW235).

Each bore investigated and the reason a sample could not be collected is presented in Appendix J. The bores

are also plotted on Figure 9 in Appendix A.

10.6.3 Additional surface water and sediment sampling in the Murrumbidgee River

Surface water and sediment samples collected from several locations along Marshalls Creek during the initial

stages of the investigation had concentrations of PFAS exceeding the laboratory LOR. Therefore, additional

surface water and sediment samples were collected in the Murrumbidgee River to further characterise the

extent of contamination at the following locations:

Confluence of Marshalls Creek (SW262). Note a sediment sample could not be collected at this location

due to the depth of water and access restrictions.

Northwest of the railway crossing (SW261). Note a sediment sample could not be collected at this location

due to the depth of water and access restrictions.

Wagga Beach (SW260 and SD260)

Wirradjuri Reserve (SW263 and SD263)

The additional sampling locations are presented on Figure 19 in Appendix A. The results of the sampling are

discussed in Section 12.3.5.2.5.

10.6.4 Shallow soil sampling at Equex

During the DSI sampling program, Jacobs identified that water from Marshalls Creek is used for irrigation of

sports grounds (McDonalds Park and Paramore Park) at the Equex facility owned and operated by Council at

the corner of Kooringal Road and Copland Street. As surface water and sediment samples collected from

several locations along Marshalls Creek during the initial stages of the investigation had concentrations of PFAS

exceeding the laboratory LOR, the DSI was expanded to include the collection of twenty shallow soil samples

from areas irrigated with water from Marshalls Creek.

The additional sampling locations are presented on Figure 37 in Appendix A. The results of the sampling are

discussed in Section 12.3.3.2.

10.7 Quality assurance and quality control

A quality assurance and quality control program was implemented during the DSI in accordance with the NEPM

and AS4482.1-2005 (Standards Australia, 2005). Key elements of the program included:

Use of qualified staff for all sampling activities

Use of standardised sampling procedures including prescribed sample storage/transport and equipment

decontamination (where applicable)

Use of NATA accredited laboratories

The collection and analysis of blind field duplicate and split samples, trip blanks and rinsate samples

Laboratory quality control protocols, including analysis of matrix spike/matrix spike duplicates, laboratory

duplicate samples and method (reagent) blanks, where applicable

The data were assessed against a set of data quality indicators and data acceptance criteria in order to assess

whether the data quality objectives outlined in Section 9 were satisfied. These indicators and criteria as well as

the results of the data validation process are presented in Appendix O.


IA147400-003-N-RPT-005 72

The data validation results presented in Appendix O indicate some minor non-conformances with the data

acceptance criteria. However, none of these non-conformances are expected to have a material impact on the

data. The data is therefore considered to satisfy the data quality objectives established for the Project.


IA147400-003-N-RPT-005 73

11. Investigation criteria

The NEPM outlines a tiered approach for the assessment of human health and ecological risks associated with

contaminated sites. Three tiers are defined as:

Tier 1 (or screening level) assessment is the first stage of assessment at the site. It includes a comparison

of known site data with published risk-based guidance levels. The assessment provides an initial screening

of the data to determine whether further assessment is required. Exceedance of Tier 1 criteria is generally

used to define the contaminants that require more detailed assessment at Tier 2.

A Tier 2 assessment is typically required when one or more contaminants are present at the site at levels

that exceed Tier 1 guidance criteria, if there are no appropriate Tier 1 criteria, or if there are unresolved and

significant uncertainties (limiting the reliability of the assessment conducted) identified in the Tier 1

assessment). Exceedance of the Tier 2 criteria trigger a Tier 3 risk assessment.

A Tier 3 assessment may be required where exceedence of Tier 2 site-specific risk-based criteria is judged

to represent a potentially unacceptable risk to human health. The Tier 3 assessment typically focuses on

the risk-driving contaminants in more detail, although studies aimed at reducing the uncertainties inherent

in the modelling of exposure pathways are also common at Tier 3.

As noted in Section 9, sample analysis results will be screened against Tier 1 criteria to provide an initial screen

of risk to human health or ecological receptors. Where results exceed the investigation Tier 1 criteria, further

assessment will be required to determine the potential for unacceptable risks to the relevant receptor (i.e. Tier 2

or 3 assessment).

There are no generic risk screening values for PFAS in the NEPM. However, the PFAS NEMP provides

guideline values to inform site investigations. These guideline values are based on existing nationally-agreed

guidelines or have been derived based on recognised processes. The PFAS NEMP notes that the guideline

values include a degree of conservatism in order to be protective of affected communities where multiple

exposure pathways may be present.

The guideline values cover risks to human health and risks to ecological receptors. The guideline values are

described in further detail in the following sections.

It is noted that the guideline values may not be adequately protective of on-Base workers involved in fire training

activities. This DSI has not assessed risks to these workers as any such assessment would be highly

dependent on the type of AFFF used, the training activities undertaken and existing health and safety controls.

Similarly, the investigation criteria may not be adequately protective of construction or maintenance workers

carrying out works in the sub-surface. Further assessment of potential risks specific to the activities of the

particular workers would be required to reach conclusions on this.

11.1 Investigation criteria for the protection of human health

11.1.1 Soil

The PFAS NEMP provides guideline values for the sum of PFOS and PFHxS and for PFOA in soil to be used

for the assessment of potential human exposure through direct soil contact. The PFAS NEMP further notes that

the guideline values should be used in conjunction with other lines of investigations to account for potential

leaching, off-site transport, bioaccumulation and secondary exposure.

The soil guideline values are based on the exposure assumptions that were used to derive the NEPM Health

Investigation Level (HIL) assumptions for specific land uses. All of the guideline values assume that 20% of the

Food Standard Australia New Zealand (FSANZ) TDI is from the exposure scenario, i.e. up to 80% of exposure

is assumed to come from other pathways. The guideline values and additional assumptions are as follows:

Residential with garden / accessible soil: These values were derived based on standard NEPM

assumptions for HIL—A including the consumption of up to 10 % plant produce grown on-site. These

values are not protective of other food-based exposures such as consumption of eggs or home-

slaughtered livestock.


IA147400-003-N-RPT-005 74

Residential with minimal opportunities for soil access: These values were derived based on standard

NEPM assumptions in HlL-B. It is useful for considering risk to human receptors where consumption of

home grown produce is not a foreseeable activity at that site and minimal opportunities exist for soil

access.

Public open space: These values were derived based on standard NEPM assumptions for HIL-C and apply

for public open space such as parks, playgrounds, playing fields (e.g. ovals), secondary schools and

footpaths. These values do not apply to undeveloped public open space such as urban bushland and

reserves.

Industrial/ commercial: These values were derived based on standard NEPM assumptions for HIL—D. The

values assume 8 hours spent indoors and 1 hour spent outdoors at a site such as a shop, office, factory or

industrial site.

To identify which particular soil guideline values to apply on the Base, the RAAF Base Wagga Zone Plan

(AECOM, 2013) defines various landuse zones. The zones are presented on Figure 2.

The PFAS NEPM guidelines for “residential with minimal opportunities for soil access” are considered

appropriate for screening risks associated with exposure to on-Base personnel in the Domestic Zone. These

values have been selected as conservative screening criteria recognising that some personnel live on Base and

that there is no food grown on the Base. Base management has also confirmed that no children live on the

Base or are present on the Base for extended periods.

For the Base Support Zone and Open Space Zone which include the recreational and open space areas on the

Base, the “public open space” guidelines have been adopted. For the remaining areas on the Base, the

industrial / commercial values will be adopted.

For off-Base locations in the areas zoned R1 General Residential such as the Forest Hill community, the

“residential with garden / accessible soil” guideline values have been adopted. These values have also been

adopted for areas around residential dwellings on properties within the RU1 Primary Production zone. However,

it is noted that these values may not be adequately protective for properties with home grown poultry and eggs.

Two properties were identified to have poultry for home grown eggs within the Study Area during the DSI. The

areas where poultry were located were not within or in close proximity to surface water drainage from the Base

and water for the poultry was from RWCC town water supply. The guideline values for “Public Open Space”

would apply in the Forest Hill recreational playing fields.

The guideline values adopted to screen the results for human health exposure to PFAS in the soils are

summarised in Table 11.1.

Table 11.1 : Adopted guideline values for PFAS in soils for the protection of human health (mg/kg) (PFAS NEMP, HEPA 2018)

Exposure Scenario PFOS+ PFHxS PFOA Comment

Domestic Zone on the Base 2 20

Based on PFAS NEMP guideline values for residential with

minimal opportunities for soil access. It is noted that no

children are present for extended periods on Base and

there is no fruit, vegetables or meat produced on Base.

Base Support Zone and Open

Space Zone on the Base 1 10

Based on PFAS NEMP guideline values for public open

space.

All other zones on the Base 20 50 Based on PFAS NEMP guideline values for commercial /

industrial land use.

Residential areas off-Base 0.009 0.1

Based on PFAS NEMP guideline values for residential

areas with garden / accessible soil. Note: May not be

adequately protective of home grown poultry / eggs.

11.1.2 Groundwater and surface water

The PFAS NEMP includes guideline values for the sum of PFOS and PFHxS and for PFOA in drinking water

and recreational water for the protection of human health. The recreational water use guidelines address


IA147400-003-N-RPT-005 75

potential exposures through whole body contact (primary contact) with water including incidental ingestion of

water and dermal contact while bathing. These are based on the guidance issued by Department of Health

(2017). The guideline values are presented in Table 11.2.

Table 11.2 : Adopted guideline values for groundwater and surface water for the protection of human health (µg/L) (Department

of Health, 2017)

Exposure scenario PFOS + PFHxS PFOA

Drinking water 0.07 0.56

Recreational water 0.7 5.6

Discussions with property owners and information from water use surveys has found that farm dams and

surface water bodies in the areas surrounding the Base are not used for supply of drinking water. Therefore, the

guideline values for recreational water will be used as the Tier 1 risk screening criteria for these surface water

bodies. RWCC extracts surface water from the Murrumbidgee River for drinking water supply and therefore the

guideline values for drinking water will be used to screen surface water data for the Murrumbidgee River.

11.2 Investigation criteria for ecological protection

The PFAS NEMP includes soil and surface water guideline values for ecological protection. Groundwater

guideline values for ecological protection have not been established.

11.2.1 Soil

The PFAS NEMP includes soil guideline values for ecological protection for both direct exposure and indirect

exposure. Direct exposure applies specifically to protection of organisms that live within, or are closely

associated with, the soil while indirect exposure considers effects on organisms associated with

bioaccumulation and / or off-site transport.

There are currently no acceptable published guideline values for direct exposure and therefore the PFAS NEMP

recommends the use of the human health guideline values as an interim measure. For indirect exposure, the

PFAS NEMP recommends the use of the 2017 Canadian Federal Environmental Quality Guidelines as interim

criteria.

The guideline values are presented in Table 11.3 below.

Table 11.3 : Adopted guideline values in soil for ecological protection (mg/kg) (PFAS NEMP, HEPA 2018)

Exposure scenario Land use PFOS PFOA

Interim soil –

ecological direct

exposure

Public open space 1 10

Interim soil

– ecological

indirect exposure

Residential and parkland 0.01 -

Commercial and industrial 0.14 -

Jacobs has assumed that the interim soil – ecological direct exposure guidelines for public open space apply to

all land. In relation to the interim soil – ecological indirect exposure guidelines, the commercial and industrial

guideline value has been adopted for land on Base with the exception of the Base Support Zone and Open

Space Zone which include the recreational and open space areas. For these areas, the residential and parkland

guideline value has been adopted. This value has also been adopted for agricultural land off-Base.


IA147400-003-N-RPT-005 76

11.2.2 Surface water

The PFAS NEMP includes guideline values for PFOS and PFOA in surface water for the protection of aquatic

ecosystems. These are based on the technical draft default guideline values developed by the Australia and

New Zealand Environment Conservation Council (ANZECC).

The PFAS NEMP states that the draft guidelines do not account for effects which result from the

biomagnification of toxicants in air-breathing animals or in animals which prey on aquatic organisms.

It is noted that the PFAS NEMP includes investigation levels for the protection of aquatic ecosystems based on

99% species protection – high conservation value ecosystems, 95% species protection – slightly to moderately

disturbed systems, 90% species protection – highly disturbed systems and 80% species protection - highly

disturbed systems. In NSW the 95% species protection level – slightly to moderately disturbed ecosystems, is

applied except for waterways that mainly flow through relatively undisturbed national parks, world heritage

areas or wetlands of outstanding ecological significance where the 99% species protection values are applied

(DEC, 2006). Therefore, the 95% species protection values have been adopted as the investigation criteria for

surface water ecological protection direct toxicity. These values are presented in Table 11.4.

It is noted that for chemicals with the potential to bioaccumulate (such as PFAS), the ANZECC Guidelines for

Fresh and Marine Water Quality (ANZECC, 2000) recommend the use of a higher level of species protection.

However, the guideline values for PFOS and PFOA for 99% species protection presented in the PFAS NEMP

are ultra-trace levels presenting significant challenges for sampling and analysis. Therefore, biota sampling has

been used for the assessment of bioaccumulation and secondary poisoning risks.

Table 11.4 : Investigation criteria for surface water ecological protection direct toxicity (µg/L) (PFAS NEMP, HEPA 2018)

Exposure Scenario PFOS PFOA

Freshwater direct toxicity, slightly to

moderately disturbed ecosystems (95%

species protection)

0.13 220


IA147400-003-N-RPT-005 77

12. Investigation Results

Maps presenting an overview of sampling locations and results are presented in Figures 10 to 17. More

detailed mapping with sample location identification numbers is presented in Figures 18 to 37.

Laboratory analysis results are summarised in tables provided in Appendix T. The full laboratory reports are

provided in Appendix U.

12.1 Geology and Hydrogeology of the Base and Gumly Gumly Wetland

As part of the investigation, seven paired groundwater monitoring well sites were installed as planned. Each

paired well site comprising one Cowra Formation and one Lachlan Formation well. Where possible the

boundary between the two strata was identified by a change in sediment colouration from red/brown in the

Cowra Formation to grey in the Lachlan Formation. Subsequent slug testing and water level monitoring was

designed to provide further information on the hydraulic properties of the two formations and the potential

connectivity between them.

12.1.1 Geology

The drilling and core recovery showed the Cowra Formation sediments to be high plasticity dense clays with

limited permeable horizons. Some weathering of the upper clay horizon (1 – 1.5 metres) is noted in some

boreholes undertaken, suggesting this is localised and discontinuous. From the borelogs provided in Appendix

H, it can be seen that the Cowra Formation is poorly sorted and typically dominated by dense clay with

occasional zones where coarser grained sediments are bound within the clay. From the observations made

during drilling there were no horizons within the unweathered Cowra Formation that were considered to be

water bearing.

The Lachlan Formation allowed quicker penetration rates during drilling with increased water strikes and core

recovery, which showed an increased presence of sands and gravels. These observations are indicative of

enhanced permeability compared to the Cowra Formation, which is consistent with the preliminary

conceptualisation.

The nature of the geology encountered did show variation between the drilling sites as expected, as the original

environment in which this geology formed was dynamic and would not lend itself to uniformity. From the seven

sites investigated the following observations have been made:

All boreholes showed a surficial clay layer which thinned to the north west

Observations during drilling were consistent with the presence of poorly sorted colluvial sediments within

the formation underlying the Base

Boreholes on elevated portions of the Base towards the east and south showed greater clay content

particularly in the upper horizons of the boreholes

Boreholes situated further towards the northern and western parts of the Base showed greater sand

content in the upper portion of the borehole

Boreholes MW300 and MW312 situated in the north west corner of the Base and Gumly Gumly Wetland

respectively were the only boreholes to encounter gravel horizons with considerably more gravel

encountered in MW312

Borehole MW312 was dominated by sands and gravels with minimal clay horizons. The surficial clay layer

was thinnest at MW312.

Two cross sections have been plotted through the Base and surrounding areas based on lithology observed in

the boreholes installed by Jacobs as well as selected public borelogs (BoM, 2017a). The sections lines are

presented on Figure 38 and the two geological sections are presented in Figure 39 and Figure 40.


IA147400-003-N-RPT-005 78

From the data collected during the drilling program and the selected public borelogs it can be seen that the

thinning of the surficial clay layer and the increased presence of sand and gravel continues to the north west.

12.1.2 Perched groundwater

As discussed in Appendix F, monitoring wells were installed where perched groundwater was encountered

during the drilling at identified potential PFAS source areas on Base. Significant moisture content in the soil was

encountered at 20 locations and wells were installed at each of these locations. However, sufficient

groundwater for sampling was only recovered from 13 wells. The locations where groundwater wells targeting

perched groundwater were installed but could not be sampled are shown on Figure 9 in Appendix A.

Observations during drilling indicated that the presence of perched groundwater was typically associated with

the interface of the fill material and Cowra Formation clays, particularly where localised weathering had

occurred. Deeper fill material was found in areas close to buildings and is assumed to have been laid down to

facilitate construction. The fill material and weathering of the upper Cowra Formation clays is discontinuous and

does not represent regional hydrogeological conditions. The presence of perched groundwater is considered to

be a result of the low permeability of the underlying alluvium and colluvium not permitting recharge to the Cowra

Formation. If the isolated areas of fill material and/or weathered upper Cowra Formation clay become saturated,

additional rainfall would drain overland.

The isolated and discontinuous nature of the perched groundwater identified in the DSI is consistent with

findings from previous investigations at the Base described in Section 6.

12.1.3 Hydrogeological Testing

Hydrogeological testing was conducted on the new deep monitoring wells and one of the perched groundwater

wells (MW101) installed by Jacobs as part of the investigation program, a bore at the Murray Cod Hatchery and

the RAAF Bore 5 observation well (MW214). All but one of the Cowra Formation monitoring wells installed by

Jacobs were dry or had a water level that was too low to conduct a test.

Hydrogeological testing comprised airlift recovery and slug testing. The results were analysed using the

Hvorslev (1951), Bouwer and Rice (1976) and Van der Kamp (1976) methods depending on the nature of the

water level response. Details of the analysis for each well are presented in Appendix N.

The Van der Kamp analysis requires an assumed storage coefficient as input data. From review of the Mid-

Murrumbidgee groundwater modelling report (O’Neil, 2007) and the Mid-Murrumbidgee groundwater model

calibration report (CSIRO, 2008), the median Lachlan Formation storage coefficient used in these models was

1 x 10-4. On this basis, a conservative value of 1 x 10-5 was used in the Van der Kamp analysis as a lower

storage coefficient leads to a higher conductivity estimate. Subsequent sensitivity analysis showed that an order

of magnitude change from 1 x 10-5 to 1 x 10-4 was not sufficient to affect the conductivity estimates shown in

Table 12.1.

Some of the testing data analysed using the Hvorslev and Bouwer Rice analyses show two or three phases in

the response, known as the double straight line effect (Bouwer, 1998). This is most pronounced for bores

MW101 and MW311 (Appendix N). The initial steep part of the response is considered to be due to water

movement within the highly permeable gravel pack surrounding the casing. Analysis of this portion will typically

overstate the conductivity estimate. The second part of the response is considered to best represent the aquifer

response and is the portion that was analysed. The final part is described as the tailing effect and analysis of

this portion will typically understate the conductivity estimate (Bouwer, 1998; Weight, 2008).

The results are presented in Table 12.1.


IA147400-003-N-RPT-005 79

Table 12.1 : Hydraulic testing results summary

Well ID Formation Method Conductivity (m/day)

Rising Head Falling Head

MW101 (BH210) Perched Bouwer Rice 0.02 0.11

MW203 (Hatchery bore) Lachlan Hvorslev 1.76 1.49

MW300 Lachlan Van Der Kamp 40

MW302 Lachlan Hvorslev 3.43

MW304 Lachlan Bouwer Rice 8.25x10-04

MW306 Lachlan Hvorslev 0.02 0.02

MW308 Lachlan Hvorslev 0.98

MW310 Lachlan Hvorslev 0.02 0.02

MW311 Cowra Hvorslev 1.2x10-04

MW312 Lachlan Van Der Kamp 5

MW214 (Observation

well for RAAF Bore 5)

Lachlan Van Der Kamp 8

The results presented in Table 12.1 are predominantly from Lachlan Formation monitoring bores. The

conductivity estimates range across several orders of magnitude in the region of the Base and the immediate

surrounds, which highlights the heterogeneity of the Lachlan Formation, as discussed in Sections 5.5 and 13.

There is a general increase in conductivity from south east to north west with the lower values in the southern

and eastern portions of the Base and the higher values in the northern and western portions. Bores MW302,

MW312 and MW214 show an increase of up to four orders of magnitude in the conductivity of the area of the

Gumly Gumly Wetland compared to the Base. The analysis for MW300 has yielded a high result relative to the

other analyses and may not be reliable.

12.1.4 Water level monitoring

12.1.4.1 Regional groundwater

Groundwater levels were measured at all locations where groundwater samples were collected as part of the

DSI. The elevation of each bore or well (top of casing) was obtained from LIDAR data provided by Council with

the exception of the wells installed by Jacobs which were surveyed by a registered surveyor.

Groundwater contours for the Cowra and Lachlan Formations have been plotted based on the measured water

levels during January 2018 and inferred elevations where bores have not been surveyed. These contours are

presented on Figures 41 and 42. The contours reflect the extent of the available data and consequently do not

cover the entire Study Area.

The Cowra Formation contours show a general head gradient to the north west, which is consistent with the

hydrogeological conceptualisation. In the vicinity of the Murray Cod Hatchery there is evidence of drawdown in

the Cowra Formation due to groundwater abstraction at this property. The abstraction occurs from the Lachlan

Formation, however from the hydrograph shown in Figure 12.3, it can be seen that drawdown in the Cowra

Formation is induced. This has the effect of locally distorting the groundwater flow paths to draw water towards

the point of abstraction.

There is also distortion in the Cowra Formation contours in the region of the former Forest Hill landfill situated to

the north of the Base. This is likely due in part to the granite outcrop situated immediately north west of the

landfill site preventing north westerly groundwater movement in the Cowra Formation causing groundwater to

move through the topographical low point immediately to the south of the landfill. Groundwater movement along


IA147400-003-N-RPT-005 80

this pathway may also be influenced by the Base irrigation bore, which abstracts from the Lachlan Formation,

however may induce drawdown in the Cowra Formation.

The water levels shown in Cowra bore MW311 (Figure 12.1) have been omitted from the contour plot as the

hydrograph shows that this water level has steadily dropped since monitoring began to reach the level of the

sump. It is therefore concluded that the water in this bore was water that could not be removed during bore

development. The latest monitoring data shows that this bore is dry, which would be consistent with the other

Cowra Formation monitoring bores installed on the Base and Gumly Gumly Wetland.

The Lachlan Formation contours show lower groundwater levels compared to the Cowra Formation and

therefore suggest the vertical hydraulic gradient is downwards between the two formations. The lateral hydraulic

gradient is also to the north west in the Lachlan Formation. Distortion is evident in the region of the Base

irrigation bore and the Murray Cod Hatchery abstraction bore, however, the Murray Cod Hatchery abstraction

does not show as drawdown in the Lachlan Formation, which may be due to the relatively low abstraction rates

at the Murray Cod Hatchery.

12.1.4.2 Water level monitoring in new wells

Following drilling and well development, water level loggers were installed in all Lachlan Formation wells and

one Cowra Formation well installed by Jacobs. The remaining Cowra Formation wells were dry or had

insufficient water for monitoring. Water level loggers were also installed in four perched groundwater wells on

Base. As discussed above, the latest monitoring data shows that Cowra bore MW311 is dry as the water level

steadily dropped to the level of the sump indicating that the water in the bore was water that could not be

removed during bore development.

The purpose of the water level logging was to assist in assessing variability in groundwater levels on seasonal

timescales and in response to rainfall events. The logging can also assist in assessing potential connectivity

between formations and the ground surface.

Figure 12.1 shows the data collected from the regional monitoring wells. The data collected from the on Base

perched wells are presented in Figure 12.2. Rainfall data from the BoM Wagga Wagga AMO station is also

presented on the hydrographs.


IA147400-003-N-RPT-005 81

Figure 12.1 : Regional groundwater hydrographs

Figure 12.2 : On- Base perched groundwater hydrographs

The data collected so far indicates little or no response in groundwater levels from the rain events and very little

change in levels overall. The Lachlan Formation bores show variations of the order 0.1m, which do not coincide

with rainfall events and are not considered to be rainfall responses.

It is however noted that the data duration shown may not be sufficient to determine a relationship between

rainfall and groundwater levels. As more data becomes available seasonal fluctuations in groundwater levels

0

5

10

15

20

25

30

35

40

45

50

165

170

175

180

185

190

195

06-Jan-18 05-Feb-18 07-Mar-18 06-Apr-18

Rai

nfa

ll (m

m)

mA

HD

Rainfall mm MW300 MW302 MW306 MW310 MW311 (Cowra) MW312

0

5

10

15

20

25

30

35

40

45

50

205

206

207

208

209

210

211

212

213

214

06-Jan-18 05-Feb-18 07-Mar-18 06-Apr-18

Rai

nfa

ll (m

m)

mA

HD

Rainfall mm MW101 MW109 MW113 MW117


IA147400-003-N-RPT-005 82

will be assessed and are expected to be most pronounced at sites where the vertical connectivity is greatest,

which would allow more rapid rainfall recharge to groundwater.

It would be expected that areas where perched water has collected would show the most rapid response to

individual rainfall events. MW101 shows minor variations with two periods of water level increase, which

coincide with the period of rainfall at the end of January and the rainfall event on 22 February. MW109 shows a

slow water level recovery since installation over a period of about one month, which suggests low hydraulic

conductivity of the screened formation.

The lack of groundwater in the Cowra Formation indicates that there would not be a vertical pathway through

this formation in the region of the base. It is therefore expected that the discharge mechanism for the areas

where perched groundwater occurs is via overland drainage once these zones become saturated.

12.1.4.3 Water level monitoring in the Murray Cod Hatchery Bores

Water level loggers were installed in the three accessible bores at the Murray Cod Hatchery:

MW203 (GW401188): Lachlan Formation monitoring well approximately 1 to 2m away from Lachlan

Formation pumping bore

MW201 (GW402595): Cowra monitoring well adjacent to pumping well

MW204 (GW401651): Lachlan monitoring well approximately 550 m south west of the pumping well

Approximately four months of data was available at the time of preparing this report. The locations of the above

wells are shown on Figure 23 and the hydrographs are shown on Figure 12.3, plotted with rainfall.

Figure 12.3 : Murray Cod Hatchery groundwater well hydrographs

0

5

10

15

20

25

30

35

40

45

50

169.5

170

170.5

Au

g-2

017

Sep

-20

17

Oct

-20

17

No

v-2

017

De

c-20

17

Jan

-20

18

Rai

nfa

ll (m

m)

Wat

er L

evel

(m

AH

D)

Rainfall (mm) GW201 (Cowra) GW203 (Lachlan Adj. pumped bore) GW204 (Lachlan south side)


IA147400-003-N-RPT-005 83

The hydrographs show an immediate response in both monitoring wells (GW203 and GW204) due to pumping

of water from the Lachlan Formation pumping bore. This response is shown as the regular periods of

groundwater drawdown, which occurs when pumping commences followed by water level recovery when

pumping ceases.

Any response to rainfall at these sites has been masked by the response to pumping, which would be a more

dominant influence on groundwater levels at the Murray Cod Hatchery. The heavy rainfall on 2 and 3 December

2017 did produce an observable response at GW204 (MW204), installed in the Lachlan formation. There is no

clear response to this event in bores GW201 (MW201) or GW203 (MW203), which may be due to their closer

proximity to the pumping bore, making the influence of pumping more dominant compared to GW204. It is also

possible that there is enhanced vertical connectivity at GW204 leading to a greater response to rainfall.

12.2 Groundwater quality – major ion analysis

Groundwater samples for laboratory analysis were collected from the groundwater wells and surface water sites

during January 2018. A major ion analysis has been conducted to categorise the water type of the different

groundwater bearing formations and the surface waters and to indicate regions where mixing may be occurring.

The results of the major ion analysis are summarised in Table 9 in Appendix T. For the purpose of the major

ion analysis the samples have been divided into the following categories:

Surface water (22 locations)

Perched groundwater (15 locations)

Cowra Formation (6 locations)

Lachlan Formation (20 locations)

Groundwater fed ponds at the Murray Cod Hatchery (9 locations)

Granite Groundwater (1 location)

It should be noted that water quality data can show considerable variability and the discussion presented in the

following section considers overarching patterns observed in the data and does not attempt to explain all

outlying data unless outliers are considered of relevance. Furthermore, the use and construction of bores not

installed during the DSI cannot be verified, which can increase the likelihood of anomalous data.

12.2.1 Cation chloride ratio

The ratio of major cations relative to chloride can be useful in illustrating differences and similarities in the major

ion chemistry across the different sampling locations. As chloride (Cl) tends to act conservatively in that it

doesn’t interact with the minerals present within the aquifers, assessing changes in the concentration of cations

relative to chloride can be useful in assessing the major processes controlling groundwater chemistry.

Figure 12.4 shows the ratio of magnesium (Mg) relative to Cl in surface and groundwater. Mg has been

selected to represent all cations as the ratio of Mg to Cl is similar to the other cation Cl trends observed.

Therefore, Mg is used as a proxy for all cations in the subsequent discussion.


IA147400-003-N-RPT-005 84

Figure 12.4 : Molar ratio of Mg to Cl against Cl concentrations

Figure 12.4 shows that the highest concentrations of Cl occur in the perched system, and that in this system,

cations do not increase relative to Cl. This indicates that Cl increases are not related to the dissolution of

minerals (which could increase the cation:Cl ratio), and are more likely to be related to evaporation of water.

Further, chloride tends to behave conservatively at higher concentrations while other ions interact with each

other and the formation material, resulting in lower cation:chloride ratios at higher salinities. This is consistent

with the presence of clays within the perched system and the underlying Cowra Formation, as clays will slow

groundwater infiltration rates, keeping it near the surface and facilitate evaporation.

Conversely, surface water contains the lowest concentration of Cl and the highest cation:Cl ratios of all water

types. Regular freshening by rainfall of surface waters will keep the Cl concentration low and cation

concentrations of surface waters can show more variability compared to groundwater due to surface run-off. It is

noted that some Lachlan Formation samples plot very similar to surface water. This similarity may be due to

localised areas of enhanced vertical connectivity and the overall enhanced hydraulic conductivity of the Lachlan

Formation permitting localised rapid recharge.

12.2.2 Piper analysis

The piper diagram in Figure 12.5 illustrates the trends in major ion chemistry for both surface water and each of

the groundwater units.


IA147400-003-N-RPT-005 85

Figure 12.5 : Piper diagram of surface and groundwater sampled at RAAF Base Wagga

The piper diagram shows two distinct populations of water types.

This first population includes water dominated by Cl and Na, and generally encompasses groundwater in the

perched system, groundwater in the underlying Cowra Formation, and surface water in the Murray Cod

Hatchery ponds that are sourced from groundwater. The similarity between the pond water the perched water

and Cowra groundwater may be due to processes happening within the ponds as the ponds are lined with clays

from the upper Cowra Formation. It may also be the case that the Lachlan Formation groundwater used to fill

the ponds are very similar to Cowra Formation groundwater in the region of the hatchery as vertical leakage

from the Cowra to the Lachlan Formation would be occurring around the Murray Cod Hatchery as shown in

Figure 12.3.

A Cowra Formation sample (MW224) plots in the lower portion of the Piper diagram, close to the Granite

sample (MW223). Whilst these bores are situated close to each other (1.4km separation in the region between

the Base and Kyeamba Creek) it is not clear why the MW224 would plot distant from most of the Cowra

Formation samples and as such is considered an outlier. It is noted that another Cowra sample (MW234) plots

just outside of the highlighted cluster containing four Cowra samples. It is not clear why this sample plots

separate to the cluster, however, given the variability observed in the other formations it is considered that

MW234 is an outlier and may be indicative of Cowra Formation variability.

From Figure 12.5, the Lachlan Formation samples that show the closest similarity to Cowra Formation water

are from wells MW300, MW312 and MW228. MW300 and MW312 are in the north west corner of the base and

the northern margin of the Gumly Gumly Wetland respectively. MW228 is the deepest well of three at a multi-

piezometer site east of Kyeamba Creek.


IA147400-003-N-RPT-005 86

There is a group of surface water samples that also appear to be Na and Cl dominated and plot closely to the

Perched/Cowra group in Figure 12.5. These include, SW230, SW231, SW232 and SW240, which were

collected from reaches of both Kyeamba Creek and Marshalls Creek, and may suggest groundwater and

surface water interaction with the perched/Cowra systems in those areas.

The second population identified in Figure 12.5 exhibits a high proportion of HCO3 relative to Cl and SO4, and

an intermediate proportion of Na + K relative to Ca + Mg. The population contains the majority of surface water

samples collected. Four groundwater samples from the Lachlan Formation exhibit similar major ion ratios to this

population. Two of these (MW210 and MW227) are located near the edge of the Murrumbidgee River,

suggesting recharge to the Lachlan Formation from the River at this location. The remaining two (MW302 and

MW308) are located in the centre of the Base and it is not clear why these sites would show similar chemistry to

surface water given that the geology indicates limited vertical connectivity between the ground surface and the

Lachlan Formation in this area. However, water quality and water level data collection is ongoing and will be

used to assess potential vertical connectivity. It is also possible that the water used during drilling is affecting

the water quality data as water consumption during drilling was greater than expected due to the high plasticity

clays encountered.

The remaining samples from the Lachlan Formation generally exhibit major ion ratios that lie somewhere

between that of the Cowra/perched system and that of surface water. This may be the result of mixing between

the respective sources within the Lachlan Formation. For example, groundwater from MW212 exhibits major ion

ratios that fall between the two identified populations. This lies along the Murrumbidgee River near Marshalls

Creek. In this area, it may be that groundwater in the Lachlan Formation is a mixture between groundwater that

has recharged vertically through the Cowra Formation and surface water that that has seeped into the Lachlan

Formation from the Murrumbidgee River.

At the Murray Cod Hatchery bores MW200, MW202 and MW203 are all situated adjacent to the pumping bore

and plot together on the Piper diagram indicating similar water types as would be expected. MW204 is situated

on the southern boundary of the Murray Cod Hatchery and plots slightly differently despite also being installed

in the Lachlan Formation and in reasonably close proximity to the other three bores. Furthermore, the PFAS

data from these bores shows that MW200, MW202 and MW203 have concentrations in the range 1 to 5 µg/L,

whilst MW204 showed concentrations in the range 0.01 to 0.07 µg/L. The differing groundwater chemistry at

these sites could be explained by the groundwater abstraction at the Hatchery leading to the differing water

quality at bores MW200, MW202 and MW203 and creating a preferential pathway for contaminant migration.

There are a number of surface water samples that also plot between the two established populations including

SW104, SW213, SW218 and SW225. Both SW104 and SW218 are located on the storm drain that discharges

onto the Gumly Gumly Wetland north west from the Base. SW225 is located along Gregadoo Creek and SW213

is located on the Murrumbidgee River close to the Gumly Gumly Private Irrigation District bore and is the only

sample from the Murrumbidgee River that exhibits a major ion signature that plots between the surface water

population and that of the perched/Cowra Formation. This could suggest groundwater discharge to the

Murrumbidgee River at this location via baseflow or may be related to the discharge of irrigation water to the

Murrumbidgee River.

12.3 PFAS sampling and analysis results

The sampling locations and results of the PFAS analysis of samples are presented on Figures 10 to 37. It is

noted that at soil sampling locations where samples were collected at multiple depths below ground level, the

maximum reported concentration has been used to present the sample result. Similarly, at surface water or

groundwater sampling locations where sampling has been conducted more than once, the maximum reported

concentration has been used.

The sample analysis results are summarised in the tables provided in Appendix T. Laboratory analysis reports

are provided in Appendix U. The summary tables and the analysis reports include the data collected from the

preliminary sampling program and the DSI.


IA147400-003-N-RPT-005 87

A discussion of the results is presented in the following sections. It is noted that unless otherwise stated in the

following sections, the concentration of PFOA in samples obtained during this investigation were below the

adopted guideline values outlined in Section 11.

12.3.1 On-Base primary source characterisation

A geoprobe drill rig was used to conduct soil sampling at locations within each identified potential PFAS source

area on Base. Soil samples were generally collected at surface, 0.5 mBGL and 3 mBGL at each location.

Shallow soil samples were also collected with a hand auger at some locations. Groundwater wells targeting

perched water were installed in several of the boreholes. The locations are presented in Figures 28 to 36.

It is noted that groundwater wells targeting regional groundwater (Cowra and Lachlan Formations) were also

installed on Base. These are discussed in Section 12.3.6.

12.3.1.1 Comparison of soil analysis results to adopted guideline values

A summary of the sampling results for PFOS, PFOS + PFHxS and PFOA in soil is presented in Table 12.2.

Table 12.2 : Summary of potential source area soil sampling results for PFOS, PFOS + PFHxS and PFOA (mg/kg)

Source Area Total

number

of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS +

PFHxS

Maximum

concentratio

n PFOA

Samples

exceeding

human

health

guideline1

Samples exceeding

ecological guideline

Direct3 Indirect4

RMV0093 - Fire Training

Area

21 20.3 21.7 0.0927 1 4 16

RMV0097 - Fire Station 19 5.5 5.58 0.0255 0 6 16

Fire Extinguisher Concrete

Pad (RMV0098) and Former

Fire Station

29 7.71 8.24 0.0599 0 8 29

RMV0179 - Abandoned

Sewage Services

9 0.0064 0.0064 <0.0002 0 0 0

Building 83 - Vehicle

Maintenance

21 0.0131 0.0159 0.0006 0 0 0


Filling Area 1

24 0.0172 0.0218 <0.0002 0 0 0


Filling Area 2

12 0.404 0.407 0.0019 0 0 2

NSW1105 - Former Bitumen

Plant and Neptune Plane

Fire Training Area.

33 0.0613 0.0626 0.0019 0 0 0

RMV0123 - Former toxic

Chemical Store

15 0.0766 0.0776 <0.0002 0 0 0

Aircraft parking area South

of Building 88

26 0.0276 0.0526 0.0024 0 0 0

Taxiway A - Fire

Extinguisher training

6 0.0051 0.0101 0.0003 0 0 0

Former Apprentices Club 12 0.0162 0.0162 0.0012 02 0 15

Historical residential building

fire

8 0.0042 0.0042 <0.0002 02 0 05


IA147400-003-N-RPT-005 88

1 PFAS NEMP human health guideline value for Industrial / Commercial land use (PFOS + PFHxS 20 mg/kg and PFOA 50 mg/kg) except

where noted

2 PFAS NEMP human health guideline value for public open space (PFOS + PFHxS 1 mg/kg and PFOA 10 mg/kg)

3 PFAS NEMP interim ecological guideline value – direct exposure (PFOS 1 mg/kg and PFOA 10 mg/kg)

4 PFAS NEMP interim ecological guideline value - indirect exposure industrial / commercial (PFOS 0.14 mg/kg) except where noted

5 PFAS NEMP interim ecological guideline value - indirect exposure residential and parkland (PFOS 0.01 mg/kg)

The most significant concentrations of PFAS in soil were reported for RMV0093 - Fire Training Area, RMV0097

- Fire Station, Fire Extinguisher Concrete Pad (RMV0098) and Former Fire Station. Only one soil sample

exceeded the adopted guideline value for human health. Sample 0906_BH248_0.5_171026 from RMV0093 -

Fire Training Area had a reported PFOS + PFHxS concentration of 21.7 mg/kg. While this exceeds the adopted

guideline value of 20 mg/kg, the sample was collected from 0.5 mBGL. A sample collected from the ground

surface in the same borehole had a reported PFOS + PFHxS concentration of 1.99 mg/kg and a sample

collected from 3 mBGL in the same borehole had a reported PFOS + PFHxS concentration of 1.83 mg/kg.

Furthermore, the following points are noted in relation to PFOS + PFHxS results for soil samples collected from

the RMV0093 - Fire Training Area:

The arithmetic mean of the results was 2.3 mg/kg (below the adopted human health guideline value)

The standard deviation of the results is 5.5 (less than 50% of the adopted human health guideline value)

The maximum value is less than 250% of the adopted human health guideline value

The 95% Upper Confidence Level (UCL) of the arithmetic mean was determined using the US EPA

ProUCL calculator (US EPA, 2015). This calculator recommended the use of 99% Chebyshev (Mean, Sd)

UCL as the best estimate of the 95% UCL. This value was determined to be 14.3 mg/kg (less than the

adopted human health guideline value) (refer to Appendix R for calculations)

Therefore, based on the depth of the sample with the PFOS + PFHxS concentration exceeding the adopted

human health guideline value and the discussion above, no unacceptable risk to human health is considered to

be present. It is noted that the guideline values do not consider risks to workers involved in sub-surface works.

Potential risks to these workers would depend upon the nature of the specific work and existing exposure

controls (e.g. Routine Personal Protective Equipment). An assessment of risks to these workers is outside the

scope of this investigation.

Reported concentrations of PFOS exceeded the PFAS NEMP interim soil – ecological direct exposure guideline

value in soil samples from three source areas and exceeded the PFAS NEMP interim soil - indirect exposure

guideline in soil samples from five source areas. Further assessment of this data will be undertaken as part of

the HHERA.


IA147400-003-N-RPT-005 89

12.3.1.2 Comparison of perched groundwater results to human health guideline values

A summary of the sampling results for PFOS + PFHxS in perched groundwater is presented in Table 12.3.

Table 12.3 : Summary of potential source area perched groundwater sampling results for PFOS + PFHxS (µg/L)

Area Number of samples Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Samples exceeding

human health

guideline1

RMV0093 - Fire Training Area 2 889 54.4 2

RMV0097 - Fire Station 2 2,660 77.4 2

Fire Extinguisher Concrete Pad

(RMV0098) and Former Fire Station

2 14,300 150 2

RMV0179 - Abandoned Sewage Services One groundwater well installed. Insufficient water for sample.

Building 83 - Vehicle Maintenance 2 17.9 0.58 2

RMV0092 - Former Land Filling Area 1 One groundwater well installed. Insufficient water for sample.

RMV0094 - Former Land Filling Area 2 One groundwater well installed. Insufficient water for sample.

NSW1105 - Former Bitumen Plant and

Neptune Plane Fire Training Area.

2 5.83 0.21 2

RMV0123 - Former toxic Chemical Store One groundwater well installed. Insufficient water for sample.

Aircraft parking area South of Building 88 4 15.9 0.45 4

Taxiway A - Fire Extinguisher training No groundwater encountered. No well installed.

Former Apprentices Club One groundwater well installed. Insufficient water for sample.

Historical residential building fire No groundwater encountered. No well installed.

1 PFAS NEMP guideline value for human health – drinking water (PFOS + PFHxS 0.07µg/L and PFOA 0.56 µg/L)

Concentrations of PFOS + PFHxS exceeded the adopted guideline value for drinking water (0.07 µg/L) in all

perched groundwater samples with the highest concentrations reported for RMV0093 - Fire Training Area,

RMV0097 - Fire Station, Fire Extinguisher Concrete Pad (RMV0098) and Former Fire Station. These were the

same source areas that had the highest reported soil concentrations. The reported concentrations of PFOA in

perched groundwater were also highest in these areas. The maximum reported concentration of PFOA was 150

µg/L. This was for a perched groundwater sample collected at the Fire Extinguisher Concrete Pad (RMV0098)

(sample ID 0906_MW101_P_171214).

Perched groundwater at the Base is discontinuous and wells yielded very little water. There is currently no

beneficial use of this groundwater unit on Base and beneficial uses in the future are considered highly unlikely.

Therefore, while the reported concentrations significantly exceed the drinking water guideline value, no

unacceptable risk to human health is present.

12.3.2 On-Base irrigation areas

As noted in Section 2.3.1.2, water from an off-Base groundwater bore operated by the Base (RAAF Bore 5) is

pumped to a water storage tower on Base and then used for irrigation of landscaped areas across the Base.

While testing of water from the bore and from the storage tower did not identify PFAS concentrations above the

laboratory LOR (see Section 7.3), sampling of shallow soil in the irrigated areas was proposed in order to

assess whether the areas may have been impacted through the use of impacted water historically.

Jacobs collected shallow soil samples from five locations within the former golf course area and four shallow soil

samples from landscaped irrigated areas along Newton Road. The results of the sampling are summarised in

Table 12.4. The sampling locations are presented on Figures 29 and 31.


IA147400-003-N-RPT-005 90

Table 12.4 : Summary of shallow soil sampling results for on-Base irrigation areas for PFOS + PFHxS (mg/kg)

Irrigation Area Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS +

PFHxS

Maximum

concentration

PFOA

Samples

exceeding

human

health

guideline1

Samples exceeding


Direct2 Indirect3

Former golf course 4 0.0003 0.0003 <0.0002 0 0 0

Landscaped areas along

Newtown Road

4 0.0031 0.0038 <0.0002 0 0 0

1 PFAS NEMP human health guideline value for public open space (PFOS + PFHxS 1 mg/kg and PFOA 10 mg/kg)


3 PFAS NEMP interim ecological guideline value - indirect exposure residential / parkland (PFOS 0.01 mg/kg)

The shallow soil sampling locations are in areas within the Base Support Zone and therefore the public open

space guidelines for human health from the PFAS NEMP have been adopted. The reported PFOS + PFHxS

concentrations are below these guideline values. It is noted that there are irrigated landscaped areas within the

Residential Zone on Base and the PFAS NEMP guideline values for residential with minimal opportunities for

soil access are higher than the guideline values for public open space.

Therefore, the reported shallow soil concentrations do not indicate an unacceptable human health risk to

personnel on Base. Furthermore, given the low permeability nature and thickness of the Cowra Formation on

Base, the irrigation areas are considered unlikely to represent a significant source of groundwater

contamination.

The reported PFOS concentrations are below the PFAS NEMP guideline values for ecological direct exposure

(1 mg/kg) and ecological indirect exposure (0.01 mg/kg). Therefore, the reported concentrations do not indicate

any unacceptable ecological risks.

12.3.3 Off-Base source characterisation

12.3.3.1 Investigation of Forest Hill STP, effluent irrigation and biosolids application areas

As noted in Section 2.4.6, the Forest Hill STP receives two sewage flows. One flow contains sewage from the

Base and approximately 20 properties in Forest Hill and Ladysmith. The other flow is from the remaining

properties in Forest Hill and Ladysmith (municipal flow). The Base sewage flow is treated in aeration ponds

while the other sewage flow is treated through a Pasveer process. The two flows currently come together within

the aeration ponds where Base sewage inflows. Historically (more than three years ago) the two flows came

together in a storage pond after treatment.

Jacobs collected samples of the wastewater immediately before the first aeration pond of sewage from the Base

(referred to as the RAAF aeration pond) as well as a sample of water from the storage pond that receives

treated effluent from the RAAF aeration ponds and from the treated municipal flow. The sampling point is

referred to as the EPA sampling point as it is one of the locations used for sampling under the STP’s

Environment Protection License.

Jacobs also collected samples of shallow soil in areas around the STP where Council staff had advised that

sludge from the treatment ponds had been applied to land.

Treated wastewater from the STP has historically been mixed with surface water from Kyeamba Creek and

irrigated to land at the former CSIRO Flushing Meadows research area to the west of the STP and also via a

360 degree pivot irrigator to the north of the STP and a 180 degree pivot irrigator to the south east of the STP.

The Flushing Meadows research area is no longer in use and the pivot irrigators are not currently using treated

effluent. Jacobs collected three shallow soil samples from the Flushing Meadows area, four co-located shallow


IA147400-003-N-RPT-005 91

soil and vegetation samples from the 360 degree pivot area and three co-located shallow soil and vegetation

samples from the 180 degree pivot area.

The sampling locations at the STP and Flushing Meadows area are presented in Figure 24. The locations at

the 360 degree pivot irrigator and 180 degree pivot irrigator are presented in Figures 20 and 25 respectively.

The results of the analysis of the wastewater are presented in Table 12.5. Analysis results for the shallow soil

are presented in Table 12.6.

Table 12.5 : Summary of analysis results for wastewater at the Forest Hill STP (µg/L)

Sample location Sample ID PFOS PFOS + PFHxS PFOA

SW229 (RAAF influent) 0906_SW229_171207 0.43 0.66 0.06

SW228 (EPA Sampling Point) 0906_SW228_171207 2.90 4.33 0.17

The reported PFOS + PFHxS concentrations at location SW228 are significantly higher than the reported

concentration in the sample collected from the same location by the NSW EPA in August, 2017 (see Table 7.2).

The reported PFOS + PFHxS concentration in the NSW EPA sample was 0.48 µg/L. The inflow sampled at

SW229 represents only the Base wastewater through inflow pipes currently. The pond at SW228 represents

treated wastewater from both the Base wastewater flow and the municipal flow. The sample from SW228 may

represent some historic accumulation from RAAF wastewater stream or from the municipal wastewater stream

for the past three years, as sediment has not historically been cleaned from these ponds and water can remain

in the pond for a number of years, depending on discharge and evaporation rates. As the sample from SW228

had a significantly higher concentration than the sample at SW229, it is possible also that PFAS contributions

from the municipal flow may be occurring. It is also possible that the treatment processes within the STP are

causing transformation of PFAS precursors.

There are no Tier 1 screening criteria for wastewater and therefore potential risks to personnel at the STP

associated with the reported concentrations will need to be further assessed as part of the HHERA. Additional

sampling is also recommended in order to better understand the variability and provide additional data for the

risk assessment.

Table 12.6 : Summary of shallow soil sampling results for the Forest Hill STP and effluent irrigation areas (mg/kg)

Area Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS +

PFHxS

Maximum

concentration

PFOA

Samples

exceeding

human

health

guideline

Samples exceeding


Direct3 Indirect

Biosolids application areas

within STP

5 0.0197 0.0202 0.0104 01 0 04

Flushing Meadows effluent

irrigation area

3 0.0061 0.0061 0.0002 02 0 05

180 degree pivot effluent

irrigation area

3 0.0056 0.0061 0.0009 02 0 05

360 degree pivot effluent

irrigation area

4 0.0061 0.0064 <0.0002 02 0 05

1 PFAS NEMP human health guideline value for industrial / commercial (PFOS + PFHxS 20 mg/kg and PFOA 50 mg/kg)

2 PFAS NEMP human health guideline value for residential with garden / accessible soil (PFOS + PFHxS 0.009 mg/kg and PFOA 0.1

mg/kg)


4 PFAS NEMP interim ecological guideline value - indirect exposure industrial / commercial (PFOS 0.14 mg/kg)

5 PFAS NEMP interim ecological guideline value - indirect exposure residential and parkland (PFOS 0.01 mg/kg)


IA147400-003-N-RPT-005 92

Reported concentrations of PFOS + PFHxS and PFOA were below the adopted guideline values and therefore

the reported concentrations are unlikely to present an unacceptable risk to health of personnel at the STP or

effluent irrigation areas. Leachability testing of soil samples collected from these areas was not undertaken.

However, leachability testing of samples collected from across the Base indicates a strong positive linear

correlation between total and leachable PFOS + PFHxS concentrations (see Section 12.3.7). Therefore, the

identified PFAS in soil is considered unlikely to be a significant source of surface water or groundwater

contamination.

Reported concentrations of PFOS in shallow soil samples from the biosolids application area and effluent

irrigation areas were below both the PFAS NEMP interim soil – ecological direct exposure guideline values and

the PFAS NEMP interim soil – ecological indirect exposure guideline values.

Of the seven vegetation samples collected from the treated effluent irrigation areas, one sample (BIO022) had a

PFAS concentrations above the laboratory LOR. The concentrations of PFOS in this sample 0.00044 mg/kg. It

is noted that treated effluent is not currently used for irrigation of these areas. However, PFAS was detected in

shallow soil and therefore the vegetation results may indicate that vegetation uptake via the root system may

not be significant.

12.3.3.2 Investigation of irrigation areas at Equex facility

Twenty shallow soil samples were collected from immediately below the grass root zone at the Equex facility,

five around McDonalds Park (locations SS255 – SS269) and fifteen at Paramore Park (locations SS250 –

SS254). It is understood based on information provided by Council that these grounds are irrigated with water

from Marshalls Creek using an in- ground sprinkler system, with drainage infiltrating through an underground

drainage system and returning to the creek. The volume and frequency of irrigation is seasonal and dependent

on maintenance activities being undertaken. Council staff advised that during peak irrigation periods (including

April 2018 when the soil sampling was undertaken), approximately 750,000 L of water is applied during the

night time period three times per week.

PFAS analysis results for the soil samples collected at the Equex facility are summarised in Table 12.7.

Table 12.7 : Summary of shallow soil sampling results at the Equex facility (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1

Number of samples exceeding

ecological guidelines

Direct2 Indirect3

20 0.0136 0.00362 0.0005 0 0 0

1 PFAS NEMP guideline value for human health – public open space (PFOS + PFHxS 1 mg/kg and PFOA 10 mg/kg)

2 PFAS NEMP guideline value for ecological - direct exposure (PFOS 1 mg/kg and PFOA 10 mg/kg)

3 PFAS NEMP guideline value for ecological - indirect exposure industrial / commercial (PFOS 0.14 mg/kg)

Reported concentrations of PFOS + PFHxS and PFOA were below the relevant guideline values for both human

health and ecological protection.

An assessment of the potential for concentrations of PFOS + PFHxS and PFOA to accumulate in shallow soil

over time through continued use of Marshalls Creek for irrigation water has been undertaken by Jacobs. Based

on a series of conservative assumptions, the assessment has identified that concentrations would not

accumulate to a point exceeding the public open space guideline value for more than 100 years. Full details of

the assessment are provided in Appendix S.

12.3.4 Sampling of groundwater at the former Council landfill at Forest Hill

The former Council landfill at Forest Hill was identified as a potential off-Base source of PFAS. Jacobs collected

groundwater samples from six groundwater wells at the landfill. The results of the sampling are presented in


IA147400-003-N-RPT-005 93

Table 12.8.The locations of the wells are presented on Figure 24. The wells are installed to depths of

approximately 10 to 20 mBGL with screened sections in the bottom 3 metres of the wells. Therefore, the wells

are considered to be screened in the Cowra Formation.

Table 12.8 : Summary of the results for groundwater sampling at the former Forest Hill landfill (µg/L)

Location Sample ID PFOS PFOS + PFHxS PFOA

MW217 0906_MW217_S_171206 <0.01 <0.01 <0.01

MW218 0906_MW218_S_171206 0.03 0.06 0.04

MW219 0906_MW219_S_171213 0.03 0.03 <0.01

MW220 0906_MW220_S_171213 0.27 0.60 0.02

MW221 0906_MW221_S_171214 0.07 0.11 0.15

MW222 0906_MW222_S_171214 0.04 0.10 0.04

Reported concentrations of PFOS + PFHxS in samples from MW220, MW221 and MW222 exceed the PFAS

NEMP guideline value for drinking water (0.07 µg/L).

Based on LIDAR data for the area and the measured groundwater levels in each well, the groundwater gradient

appears to be towards the south west. Environmental & Earth Sciences (1996) also noted that the groundwater

gradient is towards the south west and that this was probably as a result of pumping from the RAAF bores. The

natural gradient was noted to likely towards the north east.

There are no surface water drainage pathways from the Base to the former landfill. The geology of the Cowra

Formation at the Base indicates minimal potential for contaminant migration within this formation. Therefore,

based on these factors and the direction of groundwater gradient at the landfill, the PFAS concentrations at the

landfill wells are considered more likely to be due to leachate from the landfill rather than as a result of PFAS

sources on the Base.

12.3.5 Investigation of overland drainage pathways

The investigation of overland drainage pathways included sampling of soil, sediment and surface water in on-

Base drainage swales, in the discharge to Gumly Gumly Wetland, along overland flow paths to Kyeamba Creek

and Marshalls Creek and within these creeks as well as in the Murrumbidgee River.

12.3.5.1 On-Base drainage

Soil or sediment samples were collected from on-Base grass drainage swales in several areas. These swales

were dry during sampling and so no surface water samples were collected with the exception of one surface

water sample (SW105) collected from a swale in the south western portion of the Airport. The samples collected

and the results for each area are discussed below.

12.3.5.1.1 North west corner of Base

A total of five shallow soil samples were collected from the low point along a drainage swale in the north west

corner of the Base (locations SS107, SS108, SS109, SS111 and SS112). One shallow soil sample (SS110)

was collected in a low point within another apparent overland flow area nearby. The pit and pipe stormwater

network on the Base drains via underground pipes to the Council stormwater network in this area. There is an

inspection point where a sample of surface water from the invert of the on-Base stormwater pipe was collected

(location SW104). The sampling locations are presented on Figure 28. A summary of the shallow soil sampling

results is presented in Table 12.9.


IA147400-003-N-RPT-005 94

Table 12.9 : Summary of shallow soil sampling results in north west corner of the Base (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

6 0.0136 0.0141 0.0005 0 0 0

1 PFAS NEMP guideline value for human health - industrial / commercial (PFOS + PFHxS 20 mg/kg and PFOA 50 mg/kg)



While reported PFOS + PFHxS concentrations were below the applicable PFAS NEMP guideline value for the

on-Base area, community members have previously advised Defence and Jacobs that overland flow can occur

to the open space area owned by Council adjacent to the north west corner of the Base during high rainfall

events and there had been occasional inundation of stormwater to the rear of the properties adjacent to the

Council land.

One of the soil sample results on-Base exceeded the PFAS NEMP soil guideline value for human health -

residential with garden / accessible soil (0.009 mg/kg). Therefore, additional shallow soil sampling was

conducted in the Council land adjacent to the Base. Three shallow soil samples were collected along the low

point of the overland flow path (locations SS207, SS208 and SS209). Two shallow soil samples were collected

near the boundary of residential properties adjacent to the Council land (locations SS210 and SS211).

The reported concentrations of PFOS + PFHxS in one of the soil samples along the low point of the overland

flow path (location SS207 - reported concentration of 0.0103 mg/kg) slightly exceeded the PFAS NEMP

guideline value for samples human health - residential with garden / accessible soil (0.009 mg/kg). However, the

reported concentrations for the soil samples near the residential property boundaries were both well below the

guideline value.

Therefore, no unacceptable risks to human health and ecology have been identified from the soil sampling

conducted in the north west corner of the Base and adjacent Council land.

The reported concentration of PFOS + PFHxS in the surface water sample collected from the stormwater

drainage pipe on-Base (location SW104) was 0.34 µg/L, indicating PFAS emissions from the Base are

discharging to the Council stormwater network. No sediment was observed in the stormwater pipe. A significant

rainfall event had occurred in the 72 hours prior to collection of the sample (see Appendix K) and water was

observed to be flowing in the pipe at the time of sampling.

The Council stormwater network in this area drains to the Gumly Gumly Wetland and this is further discussed in

Section 12.3.5.2.

12.3.5.1.2 Drainage swale near the Fire Extinguisher Concrete Pad

Four shallow soil samples were collected in the drainage swale which runs along the rail corridor just north of

the Fire Extinguisher Concrete Pad (locations SS124 to SS127 on Figure 31). A summary of the shallow soil

sampling results is presented in Table 12.10.

Table 12.10 : Summary of shallow soil sampling results in drainage swale near fire extinguisher pad (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

4 0.375 0.383 0.003 0 0 4

1 PFAS NEMP guideline value for human health - residential with minimal access to soil (PFOS + PFHxS 2 mg/kg and PFOA 50 mg/kg)


IA147400-003-N-RPT-005 95


3 PFAS NEMP guideline value for ecological - indirect exposure residential and parkland (PFOS 0.01 mg/kg)

The area where the soil samples were collected is within the Domestic Zone and therefore the human health

guideline value for residential with minimal access to soil has been adopted. The reported concentrations are all

well below this guideline value.

Similarly, the residential and parkland value has been adopted for the assessment of indirect ecological risks.

All four samples exceed this guideline value.

This area drains to the pit and pipe network on Base that drains to the Council stormwater network in the north

west corner of the Base.

12.3.5.1.3 North western end of Runway 12/30

A total of seven shallow soil samples were collected from drainage swales around the north western end of

Runway 12/30 within the Airport (sampling locations SS138 to SS144, see Figure 30). A summary of the

shallow soil sampling results is presented in Table 12.11.

Table 12.11 : Summary of shallow soil sampling results from drainage swales in the north western end of Runway 12/30

(mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

7 0.0007 0.0007 <0.0002 0 0 0




This area drains to a farm dam on the opposite side of Elizabeth Avenue. This off-Base area is discussed

further in Section 12.3.5.2.2.

12.3.5.1.4 Drainage swales near Taxiway C

Four shallow soil samples were collected from the drainage swales on each side of Taxiway C at the Airport

(total of eight samples, locations SS153 to SS160 on Figure 32). A summary of the shallow soil sampling

results is presented in Table 12.12.

Table 12.12 : Summary of shallow soil sampling results from drainage swales near Taxiway C (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

8 0.0234 0.0242 <0.0002 0 0 0




This area drains to the pit and pipe network on Base which drains to the Council stormwater network in the

north west corner of the Base.


IA147400-003-N-RPT-005 96

12.3.5.1.5 Drainage swales near Taxiways A and D

Six shallow soil samples were collected from drainage swales near Taxiways A and D (locations SS122, SS123,

SS145, SS146, SS147 and SS148 on Figure 33). A summary of the shallow soil sampling results is presented

in Table 12.13.

Table 12.13 : Summary of shallow soil sampling results from drainage swales near Taxiways A and D (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

6 0.0596 0.065 0.0012 0 0 0




This area drains to the pit and pipe network on Base which drains to the Council stormwater network in the

north west corner of the Base.

12.3.5.1.6 Drainage channel in the eastern part of the Airport

Three sediment samples were collected from the drainage channel in the eastern area of the Airport (locations

SD101 to SD103 on Figure 33). Surface water was not present in the channel during the sampling event. A

summary of the shallow soil sampling results is presented in Table 12.14.

Table 12.14 : Summary of sediment sampling results from drainage channel in eastern part of Airport (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

3 0.0122 0.0127 0.0003 0 0 0




This drainage channel overflows on to a farm dam on the adjoining property (former dairy farm). Sampling

results for this area are discussed in Section 12.3.5.2.4.

12.3.5.1.7 Drainage in the south western corner of the Airport

Four shallow soil samples and one surface water sample were collected from drainage swales around the

Former Bitumen Plant and Neptune Plane Fire Training Area (SS131 to SS134 and SW105 on Figure 34). A

summary of the shallow soil sampling results is presented in Table 12.15.

Table 12.15 : Summary of shallow soil sampling results from drainage channel in eastern part of Airport (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

4 0.0059 0.0059 <0.0002 0 0 0


IA147400-003-N-RPT-005 97




The reported concentration of PFOS + PFHxS in the surface water sample (SW105) was 0.81 µg/L. This

exceeds the PFAS NEMP human health guideline value for recreational water (0.7 µg/L) and the PFAS NEMP

guideline value for surface water – freshwater aquatic ecology 95% species protection (0.13 µg/L).

Drainage swales in this area, including where SW105 was collected, drain runoff after rain events to a dam in

the south west corner of the Airport. Co-located surface water and sediment samples were collected from the

dam (SW/SD 100). The PFOS + PFHxS concentration in the surface water and sediment samples were 0.12 µg/L and 0.0091 mg/kg respectively. The surface water concentrations are below the PFAS NEMP guideline

values for human health – recreational use and ecological protection – freshwater 95% species protection.

12.3.5.2 Off-Base drainage

12.3.5.2.1 Drainage to Gumly Gumly Wetland

Drainage from the pit and pipe network on the Base drains to the Council stormwater network with the

connection point located in the north western corner of the Base. The Council stormwater network consists of

underground pipes that discharge to a surface water drainage channel near Elizabeth Avenue. Water in the

channel drains to the Gumly Gumly Wetland.

Jacobs collected surface water, sediment and soil samples from the Council stormwater discharge point near

Elizabeth Avenue, along the drainage channel to the Gumly Gumly Wetland and throughout the wetland. The

sampling locations are presented on Figure 22. It is noted that groundwater wells targeting the Cowra and

Lachlan Formations were also installed in the wetland. Results from these wells are discussed in Section

12.3.6.

12.3.5.2.1.1 Stormwater discharge to drainage channel near Elizabeth Avenue

There are two stormwater pipes that discharge to the drainage channel near Elizabeth Avenue. One stormwater

pipe drains stormwater from the area east of Elizabeth Avenue including the Base. This discharge has been

defined as location SW206. The second stormwater pipe drains water from the south including the area around

the NSW RFS station on Elizabeth Avenue. This discharge has been defined as location SW218. Water from

both discharges combines in a concrete pit which then overflows in to the unlined drainage channel.

Surface water from location SW206 has been sampled on three occasions while surface water from SW218 has

been sampled once. The results of this sampling are summarised in Table 12.16.

Table 12.16 : Summary of surface water sampling results at the Elizabeth Avenue stormwater discharge

Locatio

n

Sample ID Sample date Rainfall in

previous 72

hours (mm)

PFOS (µg/L) PFOS +

PFHxS (µg/L)

PFOA (µg/L)

SW206 0906_SW001_170620 20 Jun 20171 0 0.23 0.34 <0.01

SW206 0906_SW001_07072017 7 Jul 20171 21.2 0.27 0.36 0.01

SW206 0906_SW206_171213 13 Dec 2017 0 0.57 1.09 0.02

SW218 0906_SW218_180117 17 Jan 2018 0.2 <0.01 <0.01 <0.01

1 Samples collected during preliminary sampling program

Flow was observed from the stormwater pipes during each sampling event. The flow was significantly higher

during the sampling on 7 July 2017 due to the recent rainfall. Flow conditions observed during the other


IA147400-003-N-RPT-005 98

sampling events were lower. However, the flow observed at times when rainfall had not occurred for several

days may indicate infiltration to the network from irrigation runoff, wastewater or other sources.

The reported concentrations of PFOS in the samples from location SW206 exceed the PFAS NEMP guideline

value for surface water – freshwater aquatic ecology 95% species protection (0.13 µg/L). The reported

concentrations of PFOS + PFHxS in the sample collected on 13 December 2016 exceed the PFAS NEMP

guideline value for human health - recreational water.

12.3.5.2.1.2 Gumly Gumly Wetland

Co-located surface water and sediment samples were collected at three locations along the drainage channel

leading to the Gumly Gumly Wetland, from seven farm dams around the southern part of the wetland and from

one location within the drainage ditch that leads to Marshalls Creek. Summaries of the surface water and

sediment sampling results are presented in Table 12.17 and Table 12.18 respectively. Vegetation samples

were also collected from five locations within the Gumly Gumly Wetland.

Table 12.17 : Summary of surface water sampling results from the Gumly Gumly Wetland (µg/L)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration PFOS

+ PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1

Number of samples

exceeding ecological

based guidelines2

11 3.38 4.62 0.09 6 9

1 PFAS NEMP guideline value for human health – recreational water use (PFOS + PFHxS 0.7 µg/L and PFOA 5.6 µg/L)

2 PFAS NEMP guideline value for surface water – freshwater aquatic ecology 95% species protection (PFOS 0.13 µg/L)

Table 12.18 : Summary of sediment sampling results from the Gumly Gumly Wetland (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

9 0.0782 0.0795 <0.0002 0 0 4



3 PFAS NEMP guideline value for ecological - indirect exposure residential (PFOS 0.01 mg/kg)

Water was noted to be stagnant at the surface water sampling locations during sampling.

In addition to the surface water and sediment samples, soil samples were collected from 15 locations within the

wetland. Surface samples only were collected at seven of the locations while a hand auger was used at the

remaining eight locations to collect a surface soil sample and a soil sample at depths ranging from 0.3 mBGL to

1 mBGL.

Soil samples collected from deeper locations had reported PFOS + PFHxS concentrations well below the

samples collected at the surface at five of the seven borehole locations (see Figure 12.6). The deeper samples

at the remaining two locations (BH405 and BH406) had concentrations below the surface sample but the

difference was less significant.


IA147400-003-N-RPT-005 99

Figure 12.6 : PFOS + PFHxS concentrations from samples collected at surface and at depth in the Gumly Gumly Wetland

Reported PFOS + PFHxS concentrations in the surface soil samples were all below the PFAS NEMP human

health guideline value for public open space (1 mg/kg) and the PFAS NEMP ecological guideline value for direct

exposure (1 mg/kg). All of the surface soil samples had reported PFOS concentrations exceeding the PFAS

NEMP ecological guideline value for indirect exposure – residential land (0.01 mg/kg).

All of the five vegetation samples had reported PFAS concentrations above the laboratory LOR. These samples

were noted as native weeds and dried shrubs and were collected from areas where livestock was observed to

be grazing.

12.3.5.2.2 Drainage to Gregadoo Creek

There are two drainage pathways from the Base which lead to Gregadoo Creek. Surface water from the

western side of the Airport drains to a farm dam on the western side of Elizabeth Avenue (see locations SW/SD

221 on Figure 30). Water from the dam in the south western corner of the Airport can also overflow to farm

dams located on the adjacent property to the south (locations SW/SD 250 and SW/SD 251 on Figure 34) and to

another farm dam located on the western side of Elizabeth Avenue (SW/SD 222 on Figure 34).

Surface water from this area drains to Gregadoo Creek and then into Marshalls Creek. This is an ephemeral

drainage pathway consisting of farm dams with water flowing to Gregadoo Creek during extended periods of

high rainfall only.

Co-located sediment and surface water samples were collected at the four farm dams described above as well

as from eight farm dams along the Gregadoo Creek drainage pathway (see Figures 21 and 26). Co-located

shallow soil and vegetation samples were collected along each of the potential overland flow paths (locations

SS206 and SS205). Two additional vegetation samples were also collected on these paths.

A summary of the surface water results are presented in Table 12.19. A summary of the sediment and soil

sampling results are presented in Table 12.20.


IA147400-003-N-RPT-005 100

Table 12.19 : Summary of surface water sampling results from the drainage pathway to Gregadoo Creek (µg/L)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration PFOS

+ PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1

Number of samples


based guidelines2

12 0.04 0.06 <0.01 0 0



Table 12.20 : Summary of sediment and soil sampling results from the drainage pathway to Gregadoo Creek (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

14 0.0032 0.0032 <0.0002 0 0 0




All four vegetation samples had PFAS concentrations below the laboratory LOR with the exception of two of the

samples which had perfluorobutane sulfonic acid (PFBS) concentrations above the LOR. The samples were

noted to be dry felled wheat and cattle were observed to be present at two of the locations.

12.3.5.2.3 Drainage via Marshalls Creek

The area that drains via Marshalls Creek to the Murrumbidgee River is presented on Figures 19 and 21.

Surface water from the Gumly Gumly Wetland drains via an unlined ditch to Marshalls Creek. No surface water

was present in the ditch at the time of Jacobs sampling and therefore shallow soil samples were collected from

the invert of the ditch at two locations (SS233 and SS234). Another surface water ditch drains from a point

further north on Bakers Lane to the ditch that drains to Marshalls Creek. A shallow soil sample was also

collected from this ditch (SS232). Vegetation samples were collected from each of the shallow soil sampling

locations.

There is a surface water channel that flows from near Lake Albert to Marshalls Creek. Co-located surface water

and sediment samples were collected at four locations along this channel (SW/SD233, SW/SD214, SW/SD232,

SW/SD215).

Co-located surface water and sediment samples were also collected at three locations along Marshalls Creek

from adjacent to the Wagga Wagga Equex Exhibition Centre to the Murrumbidgee River (SW/SD234,

SW/SD230 and SW/SD231).

A summary of the surface water results are presented in Table 12.21. A summary of the sediment and soil

sampling results are presented in Table 12.22.

Table 12.21 : Summary of surface water sampling results for drainage via Marshalls Creek (µg/L)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration PFOS

+ PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1

Number of samples


based guidelines2

7 0.67 0.84 <0.01 1 3



IA147400-003-N-RPT-005 101


Table 12.22 : Summary of sediment and soil sampling results for drainage via Marshalls Creek (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

10 0.0337 0.0410 <0.0002 0 0 1




The surface water and sediment samples collected at locations SW/SD233, SW/SD214 and SW/SD232 indicate

no significant PFAS impacts from the Kooringal STP discharge. It is not known whether effluent is continuously

discharged from this plant or if discharge was occurring during or prior to the sampling. A previous sample

collected from the effluent discharge point by the NSW EPA (see Section 7.2) has a reported PFOS + PFHxS

concentration of <0.02 µg/L. However, several other PFAS compounds had reported concentrations above the

laboratory LOR – PFOA (0.03 µg/L), 6:2 FTS (0.21 µg/L), PFHpA (0.02 µg/L) and PFHxA (0.03 µg/L).

PFOA was also reported at concentrations above the laboratory LOR in surface water samples from locations

SW214, SW233, SW232 both upstream and downstream of the STP discharge point. PFOS and several other

PFAS compounds were detected above the laboratory LOR in the sediment sample from location SD214.

These detections occur upstream of identified pathways between source areas on Base and Marshalls Creek.

These data could indicate a potential source of PFAS upstream of the Kooringal STP discharge point to the

stormwater channel that leads to Marshalls Creek.

In relation to the reported concentrations of PFOS and PFOS + PFHxS in surface water and sediment samples

in Marshalls Creek between the Equex Centre and the Murrumbidgee River, it is noted that the cross sectional

area of the creek appears to vary along this section and this result in varying flow velocities. Some samples

were collected at points where water was clearly flowing in Marshalls Creek (SW234 and SW230) while other

samples were collected under stagnant conditions (SW231). This could explain some of the variability in the

results. It is also noted that stormwater from the surrounding East Wagga area also discharges to Marshalls

Creek in this area and there may be other PFAS sources contributing to concentrations in the creek.

During the DSI program, Jacobs was advised that water from Marshalls Creek is abstracted for use in irrigating

the playing fields at the Equex Centre (MacDonalds Park and Parramore Rugby League) during the summer

months. The water abstraction point is about 200 metres downstream of location SW234. Risks associated with

this use of water from Marshalls Creek will be assessed as part of the HHERA.

Two of the three vegetation samples had PFAS concentrations above the laboratory LOR. The sample with

PFAS concentrations below the laboratory LOR was collected next to location SS232. This location is in a ditch

that drains to Marshalls Creek and does not appear to receive runoff from the Base. The reported concentration

of PFOS + PFHxS in soil at this location was 0.0007 mg/kg, two orders of magnitude lower than the soil

concentrations reported for SS233 and SS234 which are on the drainage pathway from the Base.

12.3.5.2.4 Drainage via Kyeamba Creek

Overland flow from the eastern portion of the Airport drains to a farm dam located on the former dairy farm

adjacent to the Base. There are several farm dams located along a pathway to Kyeamba Creek. During

extended periods of high rainfall, water could drain from the farm dams to the creek.

Co-located surface water and sediment samples were collected from six farm dams between the Base boundary

and Kyeamba Creek and at five locations along Kyeamba Creek. One of the farm dams did not have water and

so a sediment sample was collected only (location SD247). Shallow soil samples were also collected at four


IA147400-003-N-RPT-005 102

locations along the overland flow pathway to Kyeamba Creek. One additional shallow soil sample (location

SS221) targeted sediment that had been recently removed by the farm dam closest to the Base and spread on

land in the area where the sample was collected. Vegetation samples (pasture material) were collected at three

of the soil sampling locations.

The sampling locations are presented on Figures 21, 23, 25 and 31. A summary of the surface water results is

presented in Table 12.23. A summary of the sediment and soil sampling results is presented in Table 12.24.

Table 12.23 : Summary of surface water sampling results for drainage via Kyeamba Creek (µg/L)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration PFOS

+ PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1

Number of samples


based guidelines2

10 0.07 0.13 <0.01 0 0



Table 12.24 : Summary of sediment and soil sampling results for drainage via Kyeamba Creek (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

16 0.0119 0.0126 <0.0002 0 0 1




Reported concentrations of PFOS + PFHxS and PFOA were below the laboratory LOR in all surface water and

sediment samples collected from Kyeamba Creek. No rainfall had occurred in the 72 hours prior to sampling at

these locations and flow in Kyeamba Creek was observed to be low or very low.

Reported concentrations of PFOS + PFHxS were above the laboratory LOR but below the Tier 1 risk screening

guidelines in the samples collected between the Base and Kyeamba Creek. The highest concentration in

surface water was 0.13 µg/L, reported for location SW249, collected in the farm dam closest to the Base. The

highest concentration in soil or sediment was 0.0126 mg/kg, collected in the overland flow path from the Base to

the nearest farm dam.

Two of the three vegetation samples had PFAS concentrations above the laboratory LOR confirming PFAS

uptake in pasture material.

12.3.5.2.5 Murrumbidgee River

The Murrumbidgee River flows from east to west. Co-located surface water and sediment samples were

collected at three locations on the Murrumbidgee River between Kyeamba Creek and Marshalls Creek.

Samples were also collected at a location upstream of Kyeamba Creek. Following a review of surface water and

sediment data for Marshalls Creek, additional samples were collected in the Murrumbidgee River at the

confluence of Marshalls Creek and downstream of the confluence.

A surface water sample from the RWCC Murrumbidgee River abstraction point was collected during the

preliminary sampling program (location SW205). Sampling at this location was also conducted during the DSI.

Sediment sampling was not possible at location SW205 or at the locations at the confluence of Marshalls Creek

(SW262) and immediately downstream (SW261) due to the depth of water and access restrictions.


IA147400-003-N-RPT-005 103

The sampling locations are presented on Figures 19 and 20. A summary of the surface water results is

presented in Table 12.25. A summary of the sediment sampling results is presented in Table 12.26.

Table 12.25 : Summary of surface water sampling results for the Murrumbidgee River (µg/L)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration PFOS

+ PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1

Number of samples


based guidelines2

9 <0.01 <0.01 <0.01 0 0



Table 12.26 : Summary of sediment sampling results for the Murrumbidgee River (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

6 0.0008 0.0008 <0.0002 0 0 0




Reported concentrations of PFOS + PFHxS and PFOA were below the laboratory LOR in all surface water

samples. The result for location SW205 (<LOR) was consistent with the sample collected from this location

during the preliminary sampling program in June 2017.

12.3.6 Investigation of regional groundwater

An overview of regional groundwater PFAS sampling results is provided in Figures 16 and 17.

12.3.6.1 Installed wells

Paired groundwater wells sets were installed at six locations on Base and one location in the Gumly Gumly

Wetland. Each set consisted of a well with screened sections targeting the Cowra Formation and a well with

screened sections targeting the Lachlan Formation. Samples were collected from all of the Lachlan Formation

wells. Groundwater wells were sampled twice in January 2018 and April 2018. Only one Cowra Formation well

(location MW311) yielded sufficient water for sampling during January 2018.

The maximum concentrations reported from the sampling are presented in Table 12.27. These were reported in

January 2018. Results from sampling in April 2018 for PFOS, PFOS + PFHxS and PFOA were below the

laboratory limit of reporting for all wells on Base (<0.01 µg/L).

Table 12.27 : Summary of PFAS sampling results for the newly installed wells (µg/L)

Location Description Target Formation PFOS PFOS + PFHxS PFOA

MW300 North west corner of Base Lachlan <0.01 0.03 <0.01

MW301 Cowra Insufficient water

MW302 Near Hannah Street on

Base

Lachlan 0.01 0.01 <0.01


MW304 Lachlan 0.01 0.01 <0.01


IA147400-003-N-RPT-005 104

Location Description Target Formation PFOS PFOS + PFHxS PFOA

MW305 Western part of Airport on

Base

Cowra Insufficient water

MW306 Southern part of Base Lachlan <0.01 <0.01 <0.01


MW308 Near athletics track on

Base

Lachlan <0.01 <0.01 <0.01


MW310 Eastern part of Airport on

Base

Lachlan <0.01 <0.01 <0.01

MW311 Eastern part of Airport on

Base

Cowra 0.01 0.04 <0.01

MW312 Gumly Gumly Wetland Lachlan 0.02 0.10 <0.01


Reported concentrations of PFOS + PFHxS were below the PFAS NEMP guideline value for human health -

drinking water (0.07 µg/L) in all samples except the sample from location MW312 which reported concentrations

between 0.08 µg/L (April 2018) to 0.1 µg/L (January 2018). The reported concentration in this sample was

above the PFAS NEMP guideline value for human health - drinking water but below the PFAS NEMP guideline

value for human health - recreational water use (0.7 µg/L).

12.3.6.2 Point of use sampling

Groundwater samples were collected from 28 existing groundwater bores in the area around the Base. This

excludes the groundwater sampling at the former Forest Hill landfill discussed in Section 12.3.4. Surface water,

sediment and soil samples were also collected at the Murray Cod Hatchery and the property adjacent to the

hatchery. These results are discussed in the following sections.

12.3.6.2.1 Drinking water supply bores

There are five groundwater bores that were identified as drinking water supply bores. Results for these bores

are presented in Table 12.28.


IA147400-003-N-RPT-005 105

Table 12.28 : Summary of groundwater sampling results for drinking water supply bores (µg/L)

Location Location ID Sample date PFOS + PFHxS PFOA

RWCC East Wagga

Borefield

MW211 20/6/2017 <0.01 <0.01

MW211 4/12/2017 <0.01 <0.01

MW212 20/6/2017 <0.01 <0.01

MW212 4/12/2017 <0.01 <0.01

MW213 20/6/2017 <0.01 <0.01

MW213 4/12/2017 <0.01 <0.01

Gumly Gumly Private

Irrigation District

MW210 20/6/2017 <0.01 <0.01

MW210 12/1/2018 0.03 <0.01

MW210 21/2/2018 <0.01 <0.01

Property north of Base MW209 7/9/2017 <0.01 <0.01

MW209 12/1/2018 <0.01 <0.01

All of the reported concentrations of PFOS + PFHxS and PFOA were below the laboratory LOR with the

exception of the sample from the Gumly Gumly Private Irrigation District bore (MW210) collected on 12 January

2018. It is noted that two additional quality control samples were collected from the bore during the 20 June

2017 sampling event (blind replicate and split samples). Both quality control samples had reported PFOS +

PFHxS and PFOA concentrations below the laboratory LOR. Jacobs requested that the lab re-analyse the

sample collected on 12 January 2018. The re-analysis was performed twice and concentrations of PFOS +

PFHxS for both re-analysis was 0.05 µg/L. The initially reported concentration of 0.03 µg/L and results of the

reanalysis are within the margin of error reported by the laboratory, and both concentrations are below the

investigation criteria for drinking water. The primary analysis result of 0.03 µg/L therefore has been adopted.

The reported concentration of PFOS + PFHxS in the sample collected from the Gumly Gumly Private Irrigation

District bore on 12 January 2018 was below the PFAS NEMP guideline value for human health - drinking water.

Furthermore, a groundwater sample collected from well MW231 located approximately 1km south west

(upgradient) from the GGPID bore had PFAS concentrations below the laboratory LOR. This well is also

screened in the Lachlan Formation. Further assessment of the potential for variability at the GGPID bore will be

undertaken as part of the HHERA.

12.3.6.2.2 Murray Cod Hatchery

12.3.6.2.2.1 Soil and sediment

Shallow soil samples were collected from 10 locations across the hatchery. Sediment samples were collected

from aquaculture ponds or discharge areas at nine locations. There was no surface water present at eight of

these locations and so the sediment was exposed to air. At seven of the sediment sampling locations, samples

were collected at surface and at a depth ranging from 0.3 to 1 mBGL. The results of the soil and sediment

sampling are summarised in Table 12.29.


IA147400-003-N-RPT-005 106

Table 12.29 : Summary of soil and sediment sampling results for the Murray Cod Hatchery (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

9 0.021 0.0224 <0.0002 7 0 6

1 PFAS NEMP guideline value for human health – residential with garden / accessible soil (PFOS + PFHxS 0.009 mg/kg and PFOA 0.1

mg/kg)



The PFAS NEMP guideline for human health – residential with garden / accessible soil has been selected for

risk screening as the hatchery operator resides at the hatchery.

The sediment sampling results are presented in Figure 12.7. Results for samples at depth are consistently

lower than the surficial samples with the exception of location SD281. Gravel was encountered at this location.

The sediment type at SD275 was sand and the difference in the shallow and deeper sample concentrations was

less than for the remaining locations where clay was encountered.

Figure 12.7 : Sediment sampling results at the Murray Cod Hatchery

12.3.6.2.2.2 Surface water

Surface water samples were collected at five locations in the hatchery during the DSI sampling program. Two

additional surface water sampling locations were established during the preliminary sampling program. A

summary of the results from both the preliminary sampling and the DSI is presented in Table 12.34.


IA147400-003-N-RPT-005 107

Table 12.30 : Summary of surface water sampling results at the Murray Cod Hatchery (µg/L)

Location Sample date PFOS PFOS + PFHxS PFOA Above screening

values for human

health and

ecological

protection

SW200 (south west

corner of hatchery) 7/07/2017 5.4 7.04 <0.01

Yes

SW201 (Pond near

MW204) 7/07/2017 5.66 6.82 0.11

Yes

SW202 (Pond A4) 7/07/2017 1.05 3.17 0.1 Yes

19/02/2018 2.38 2.55 0.07 Yes

SW203 (Pond A1) 7/07/2017 0.93 2.8 0.05 Yes

SW208 (Pond A2) 6/11/2017 0.64 1.58 0.06 Yes

10/01/2018 0.74 2.47 0.05 Yes

SW209 (Pond A2) 6/11/2017 0.62 1.48 0.06 Yes

10/01/2018 0.49 2.07 0.05 Yes

SW210 (Pond A3) 6/11/2017 0.7 1.51 0.04 Yes

10/01/2018 0.56 2.53 0.06 Yes

SW211 (Pond A3) 6/11/2017 0.67 1.56 0.05 Yes

10/01/2018 0.95 2.8 0.06 Yes

The reported concentrations of PFOS + PFHxS in all surface water samples exceeded the PFAS NEMP

guideline values for human health (drinking water and recreational water use) and ecological protection (surface

water – freshwater aquatic ecology 95% species protection).

Where multiple samples were collected at the same location, the results were generally consistent except for

SW202 where the PFOS + PFHxS concentration in February 2018 was more than double the concentration in

the sample collected in July 2017. As noted in Section 12.3.6.2.2.3, PFAS concentrations in the groundwater

supply well at the hatchery were significantly lower in January 2018 than in July 2017 and therefore the higher

result the SW202 February 2018 sample may be due to evaporation effects on the pond.

12.3.6.2.2.3 Groundwater

Groundwater samples were collected from five bores at the Murray Cod Hatchery on two occasions. The results

are summarised in Table 12.31. The summary includes results from the preliminary sampling program and the

DSI.

Table 12.31 : Summary of groundwater sampling results for the Murray Cod Hatchery (µg/L)

Location ID In use? Target

formation

Sample date PFOS + PFHxS PFOA Above

screening

value?

DW1

Rec2

MW200 Yes Lachlan 7/07/2017 3.36 0.08 Y Y

17/01/2018 1.25 0.03 Y Y

MW201 No Cowra 7/07/2017 2.60 0.06 Y Y

20/2/2018 1.04 0.02 Y Y


IA147400-003-N-RPT-005 108

Location ID In use? Target

formation

Sample date PFOS + PFHxS PFOA Above

screening

value?

DW1

Rec2

MW202 No Lachlan 7/07/2017 2.86 0.07 Y Y

17/01/2018 1.29 0.04 Y Y

MW203 No Lachlan 7/07/2017 4.48 0.08 Y Y

20/2/2018 1.4 0.04 Y N

MW204 No Lachlan 7/07/2017 0.07 <0.01 N N

1PFAS NEMP guideline value for human health – drinking water (PFOS + PFHxS 0.07 µg/L and PFOA 0.56 µg/L)

2PFAS NEMP guideline value for human health – recreational water use (PFOS + PFHxS 0.7 µg/L and PFOA 5.6 µg/L)

MW200 is the only bore currently in-use at the hatchery. This bore supplies water to the aquaculture ponds and

fish holding tanks within the hatchery building.

It is noted that water samples were collected from the end of the pipe used to fill pond A2 (location ID OTH200)

at the hatchery during the preliminary sampling program in June and July, 2017 (see Section 7.3). Water at this

point is supplied from the bore identified as MW200. The concentrations of PFOS + PFHxS in these samples ranged from 3.08 to 3.25 µg/L, consistent with the concentration in the sample from MW200 on 7 July 2017.

The reported concentrations of PFOS + PFHxS in the hatchery groundwater bore samples were significantly

lower during the January and February 2018 sampling than in the July 2017 sampling. This may be due to

increased groundwater pumping during the summer period.

Reported concentrations of PFOS + PFHxS were significantly lower in samples from well MW204, located on

the southern side of the hatchery, than the other bores at the hatchery. As noted in Section 12.1.4.3, water

level monitoring indicates a strong influence from pumping in well MW200 on groundwater levels at MW204.

Therefore, there is good connectivity between groundwater in the Lachlan Formation in these wells. However,

water chemistry information suggests that the groundwater at MW200 and nearby bores is of a different quality

than groundwater at MW204 (see Section 12.2). Therefore, the pumping at MW200 may be drawing

contaminants away from MW204.

12.3.6.2.3 Property adjacent to Murray Cod Hatchery

The property adjacent to the Murray Cod Hatchery was once part of the hatchery and there are several former

aquaculture ponds on the property. During the preparation of the preliminary conceptual site model, Jacobs was

advised that the former ponds were occasionally used for storage of surface water and that this surface water

was occasionally used to irrigate gardens on the property including gardens used for growing fruit or

vegetables.

Six co-located surface water and sediment samples were collected from former aquaculture ponds or dams on

the property. A further five sediment samples were collected from former ponds or dams where no surface water

was present. Two soil samples were collected from the vegetable gardens on the property. No fruit or

vegetables were being grown in the garden during the sampling period.

The results of the surface water sampling are summarised in Table 12.32. The results of the soil and sediment

sampling are summarised in Table 12.33.


IA147400-003-N-RPT-005 109

Table 12.32 : Summary of surface water sampling results for the property adjacent to the Murray Cod Hatchery (µg/L)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration PFOS

+ PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1

Number of samples


based guidelines2

6 1.43 1.81 0.03 3 5



Table 12.33 : Summary of soil and sediment sampling results for the property adjacent to the Murray Cod Hatchery (mg/kg)

Number of

samples

Maximum

concentration

PFOS

Maximum

concentration

PFOS + PFHxS

Maximum

concentration

PFOA

Number of samples

exceeding health

based guidelines1



Direct2 Indirect3

13 0.0183 0.019 <0.0002 4 0 3

1 PFAS NEMP guideline value for human health – residential with garden / accessible soil (PFOS + PFHxS 0.009 mg/kg and PFOA 0.1

mg/kg)



The soil samples collected from the vegetable garden (SS238 and SS239) had reported PFOS + PFHxS

concentrations well below the PFAS NEMP guideline value for human health – residential with garden /

accessible soil.

Further assessment of the surface water and sediment concentrations exceeding the Tier 1 screening

guidelines will be undertaken as part of the HHERA.

12.3.6.2.4 Other groundwater bores

Of the remaining 18 existing groundwater bores sampled, PFOS + PFHxS or PFOA concentrations above the

laboratory LOR were reported for samples from 5 bores. These results are summarised in Table 12.34.

Table 12.34 : Summary of off-Base groundwater bores not used for drinking water supply with PFAS concentrations above

LOR (µg/L)

Location

ID

Purpose In use? Target

formation

Sample date PFOS +

PFHxS

(µg/L)

PFOA

(µg/L)

Above

screening

value?

DW1

Rec2

MW215 RAAF observation well

for Bore 5

Yes Lachlan 20/06/2017 0.06 <0.01 N N

16/01/2018 <0.01 <0.01 N N

MW223 Irrigation No Granite 9/01/2018 0.30 <0.01 Y N

MW233 Irrigation of lawns and

garden (no food

production)

Yes Cowra 20/02/2018 0.18 <0.01 Y N

OTH206 Irrigation Yes Lachlan 7/09/2017 <0.01 <0.01 N N

12/01/2018 0.02 <0.01 N N


IA147400-003-N-RPT-005 110

Location

ID

Purpose In use? Target

formation

Sample date PFOS +

PFHxS

(µg/L)

PFOA

(µg/L)

Above

screening

value?

DW1

Rec2

OTH207 Stock (trough) Yes Cowra 7/09/2017 0.18 <0.01 Y N

12/01/2018 0.26 <0.01 Y N

1 PFAS NEMP guideline value for human health – drinking water (PFOS + PFHxS 0.07 µg/L and PFOA 0.56 µg/L)


There was a large variation in PFOS + PFHxS concentrations between the two samples collected from MW215.

This well was also sampled in June 2016 (GHD, 2016) and the reported concentration of PFOS + PFHxS in the

sample was 0.04 µg/L. It is understood that the RAAF irrigation bore does not operate during the winter period

and therefore the variability in the results for MW215 may be as a result of the RAAF Irrigation bore pumping.

MW223 is situated to the north east of the Base and is installed in the granite formation, which underlies the

alluvium. The publicly available drilling log for this bore indicates it was installed in 1956 and the geology

consists of clay from surface to 36 mBGL followed by weathered granite to 44 mBGL and granite to 49 mBGL.

The screened section of the bore is from 45 to 48 mBGL. Given the hydraulic properties of the clay in this area

and the depth of the screened section, a pathway for migration of PFAS from the Base via groundwater is

difficult to conceptualise. Minor concentrations of PFAS were identified in surface water and sediment or soil

samples collected along the adjacent overland drainage pathway from the Base to Kyeamba Creek. Given the

age of the bore, it is possible that PFAS migration down the bore construction may have occurred historically

during overland flow events.

There are no other known groundwater users in the area surrounding well MW223. Further assessment of

potential groundwater migration in the direction of this bore and resampling of the bore has been recommended

as part of the HHERA.

The sample at MW233 was collected from a tap connected to an existing registered bore located approximately

800 meters north of the Gumly Gumly Wetland. The registered bore details indicate the bore is 15.5 meters

deep and was installed in 1987. Water from the bore is used for irrigating the lawns at the hotel on the property

where the bore is located.

The water sample collected at OTH206 was from a tap connected to a groundwater bore. The sampling location

is shown on Figure 22 in Appendix A. The groundwater bore that supplies this tap is located approximately 100

meters north of the sampling location. The registered bore details indicate the bore is 73 meters deep with

screened sections at 60 – 63m and 69 – 72 meters below ground surface. The bore was installed in 2009. Water

from the bore is used for irrigation of lawns and fruit trees. Both samples collected from this tap during the DSI

had reported PFAS concentrations below the PFAS NEMP guideline value for human health - drinking water.

The water samples at location OTH207 were collected from a stock trough in close proximity to bore MW206. The

property owner stated that the water for the trough was sourced from a bore that is 25 meters deep and therefore

the sample has bene noted as from the Cowra Formation in Table 12.34. However, the property owner was not

able to identify the location of the bore. Both water samples collected during the DSI has PFOS + PFHxS

concentrations above the PFAS NEMP guideline value for human health - drinking water. The trough is for

watering of beef livestock.

Reported PFOS + PFHxS concentrations exceed the PFAS NEMP guideline value for human health - drinking

water in samples from several bores. Therefore, further assessment of potential risks will be undertaken as part

of the HHERA.


IA147400-003-N-RPT-005 111

12.3.7 PFAS leachability

The potential for PFAS to leach from soil was assessed through preparation and analysis of leachate from 67

soil samples using deionised water was used for the leaching fluid.

Figure 12.8 presents the relationship between total PFOS + PFHxS concentrations and leachable PFOS +

PFHxS concentrations. One sample was removed from the data set plotted in Figure 12.8. Sample ID

0906_BH248_0.5_171026 had a PFOS + PFHxS concentration of 21.7 mg/kg (highest concentration detected in soil during the DSI) and a leachable PFOS + PFHxS concentration of 14.3 µg/L. This leachable concentration

is significantly lower than expected and is considered an outlier. With the removal of this data point, the

coefficient of correlation is 0.9, indicating a strong positive linear correlation between total and leachable PFOS

+ PFHxS concentrations.

No strong correlations were observed between leachable PFOS + PFHxS and other soil parameters such as

%clay, cation exchange capacity and total organic content.

The leachable analysis confirms that there is a potential for leaching of PFAS from soil at the Base.

Figure 12.8 : Scatter plot of total and leachable PFOS + PFHxS concentrations in soil


IA147400-003-N-RPT-005 112

13. Refined Conceptual Site Model

This section presents a refined conceptual site model based on the information and data obtained during the

DSI.

13.1 Sources of PFAS contamination

Potential sources of PFAS contamination were identified in the Preliminary CSM (see Section 8.2). These

sources have now been reviewed based on the DSI findings and those confirmed (those with concentrations

above adopted investigation criteria) are presented in Table 13.1.

Table 13.1 : Identified PFAS sources

Potential source identified in

Preliminary CSM

Confirmed

source?

Comments

On-Base primary sources

RMV0093 - Fire Training Area Yes Maximum concentrations of PFOS + PFHxS in soil samples from these

areas ranged between 6 to 23 mg/kg. RMV0097 - Fire Station Yes

Fire Extinguisher Concrete Pad

(RMV0098) and Former Fire Station

Yes

RMV0179 - Abandoned Sewage Services No Maximum concentrations of PFOS + PFHxS in soil samples from these

areas were less than 0.5 mg/kg. Building 83 - Vehicle Maintenance No

RMV0092 - Former Land Filling Area 1 No

RMV0094 - Former Land Filling Area 2 No

NSW1105 - Former Bitumen Plant and

Neptune Plane Fire Training Area.

No

RMV0123 - Former toxic Chemical Store No

Aircraft parking area South of Building 88 No

Taxiway A - Fire Extinguisher training No

Former Apprentices Club No

Historical residential building fire No

On-Base secondary sources

Irrigation areas No The irrigation areas on Base were noted in the Preliminary CSM as

potential secondary PFAS sources. Sampling of the irrigation water supply

bore (RAAF Bore 5) on three occasions has not identified PFAS

concentrations about the laboratory LOR. PFAS concentrations in shallow

soil within the irrigation areas are below the relevant PFAS NEMP human

health guideline values and considered unlikely to be a significant source of

contaminants leaching to groundwater. The positive correlation between

total and leachable PFOS + PFHxS concentrations provides a further line

of evidence to suggest this is not a source i.e. low concentrations are less

leachable.

Stormwater and sewer infrastructure Yes Elevated concentrations of PFAS were detected in the stormwater

discharged to the Council stormwater network and also in the Forest Hill

STP. Therefore, there is the potential that PFAS in this infrastructure is

leaching and contributing to PFAS discharges.

Off-Base primary sources

Forest Hill RFS No No soil or groundwater investigations targeting this potential source were

undertaken. However, a surface water sample was collected from the


IA147400-003-N-RPT-005 113

Potential source identified in

Preliminary CSM

Confirmed

source?

Comments

Council stormwater pipe that drains the area where the RFS station is

located (SW218) and reported PFAS concentrations in this sample were

below the laboratory LOR. Sampling of surface water at this point during

higher flow conditions is recommended to assist in confirming if there is

PFAS at this source contributing to discharges to the wetland.

Forest Hill STP Yes Sampling of treated effluent at the Forest Hill STP identified significant

concentrations of PFAS. Further assessment of potential risks to workers

at the STP and the use of treated effluent in the future will be undertaken

as part of the HHERA.

Kooringal STP No Sampling of surface water and sediment upstream and downstream of the

Kooringal STP did not identify significant PFAS impacts from this source.

Former Council landfill at Forest Hill Yes Sampling of groundwater wells in the landfill area identified PFAS

concentrations above the PFAS NEMP guideline value for human health -

drinking water in one well. The PFAS concentrations are considered to

have been caused by leachate from the landfill.

Off-Base secondary sources

Treated effluent application areas around

the Forest Hill STP

No Reported concentrations of PFAS in shallow soil in these areas were below

the relevant PFAS NEMP guideline values for human health. However

further assessment of the potential for leaching of PFAS to surface water

and groundwater from these areas is recommended as part of the HHERA.

Gumly Gumly Wetland Yes The DSI has found that PFAS is transported in surface water from the Base

to the wetland and soil, surface water and sediment within the wetland is

impacted. The Cowra Formation is less thick in the wetland area than on

Base and water level monitoring at the Murray Cod Hatchery indicates

connectivity between the Cowra and Lachlan Formations and therefore the

potential for vertical migration of contaminants in the area. Therefore, the

wetland is still considered to be a secondary source of PFAS

contamination.

13.2 Transport pathways

13.2.1 Surface water drainage

Concentrations of PFAS in sediment and surface water samples collected along the Gregadoo Creek pathway

and within Kyeamba Creek indicate that the transport of PFAS from the Base along these pathways is not

significant. PFOS + PFHxS concentrations above the PFAS NEMP guideline value for human health – drinking

water are limited to farm dams close to the Base.

Significant concentrations of PFAS were detected in the stormwater discharge from the Base to the Council

stormwater network, in the surface water discharge to Gumly Gumly wetland and in the surface water and

sediment samples along the Marshalls Creek pathway to the Murrumbidgee River.

Reported PFAS concentrations in surface water and sediment samples in the Murrumbidgee River were below

the laboratory LOR except for two sediment samples (SD239 and SD244) which had PFOS + PFHxS

concentrations marginally above the laboratory LOR. Further investigation of the Murrumbidgee River has been

recommended in Section 15 in order to better understand the extent of PFAS impacts.

13.2.2 Geology and Hydrogeology of the Base and Gumly Gumly Wetland

As discussed in Section 12, localised occurrences of perched groundwater were found associated with fill

material on the Base. The fill material is typically less than one metre thick, discontinuous and underlain by the

surficial clay layer of the upper alluvium/colluvium. As such, perched groundwater is not considered to represent


IA147400-003-N-RPT-005 114

a lateral or vertical transport mechanism, with perched water being present in localised pockets of fill material or

disconnected weathered zones at the interface of the fill material and the upper Cowra Formation clay horizons.

Water discharge from the perched systems would occur as overland drainage when the weathered clay and fill

material becomes saturated.

The Cowra Formation at the Base was found to be dominated by dense high plasticity clays. Any horizons of

more permeable material were limited to sandy clays or minor sand lenses that typically did not produce any

water. Following the removal of drilling fluids, all Cowra Formation wells with the exception of MW311 were

found to be dry. On this basis it is difficult to conceptualise a vertical migration pathway from the surface to the

Lachlan Formation on the Base, based on the selected drilling locations, which are considered to provide a

reasonable coverage of the area.

The preliminary conceptualisation presented in Section 5.5, based on a desktop assessment of publicly

available drilling logs and other investigations provide by Defence, notes the reduced permeability of the Cowra

Formation relative to the Lachlan Formation and that any permeable horizons are considered to be discrete and

laterally impersistent. Based on observations during the DSI this conceptualisation can now be refined.

In the area of the Base, the nature of the core recovered and the dry Cowra Formation wells indicate that the

Cowra Formation acts more like an impermeable confining layer over the Lachlan Formation and cannot be

considered a water bearing formation or even a pathway for vertical PFAS migration.

At the Murray Cod Hatchery however, the relationship between the Lachlan and Cowra Formation hydrographs

(refer to Section 12, Figure 12.3) show a good degree of hydraulic connectivity. It should also be noted that the

Lachlan Formation water levels measured on the Base (refer to Section 12, Figure 12.1) are below the inferred

boundary between the Lachlan Formation and the Cowra Formation indicating an unconfined aquifer, whereas

the water level in MW312, installed adjacent to the Gumly Gumly Wetland shows a water level above the

inferred boundary.

The surface water drainage in this area, such as the Gregadoo Creek and the tributaries to the Kyeamba Creek

typically comprise ephemeral watercourses formed of disconnected farm dams. Given the low permeability of

the Cowra Formation it is inferred that these water courses do not provide recharge to groundwater and given

that the Cowra Formation wells close to the Base were found to be dry, it is inferred that the groundwater does

not provide base flow to the water courses. Due to the groundwater levels and the nature of the geology closer

to the Murrumbidgee River there is likely to be more groundwater / surface water interaction in this region during

times of higher groundwater levels or under flood conditions. South of the river towards the Base the

topographic elevation increases, groundwater levels are deeper below ground and the geology is less

permeable. As such it is considered that the surface water courses are pathways for surface drainage and do

not interact with the groundwater.

The relationship between the Gumly Gumly Wetland and groundwater is not well understood at this stage. The

paired groundwater monitoring site installed on the northern fringe encountered groundwater at approximately

14 mBGL and the Cowra Formation monitoring well installed at the Murray Cod Hatchery shows a groundwater

level of approximately 13 mBGL (refer to Section 12, Figure 12.3), suggesting that the wetland is not

groundwater fed. The wetland is in a low lying area and has its own catchment plus the runoff captured in the

stormwater drainage from the Base. It is possible that this surface run off is sufficient to support the wetland and

the discharge into Marshalls Creek, which runs along the southern boundary of the Murray Cod Hatchery.

13.2.3 Geology and Hydrogeology in the Northern Part of the Study Area

Publicly available borelogs for wells installed closer to the Murrumbidgee River show the upper reaches of the

alluvium to contain more coarse grained sediments and in some cases indicate vertical hydraulic connectivity

throughout the alluvium.

Discussions with RWCC indicate that their water supply bores have a high resilience to drought and appear to

show a good degree of connectivity with the Murrumbidgee River. The publicly available logs from those bores

show a high content of gravels and sands overlain by approximately 10 m of clay. The Environmental

Assessment Report for the Wagga Wagga Sand and Gravel Quarry Extension (Hanson, 2010) states that seven


IA147400-003-N-RPT-005 115

bores were drilled for that project, all of which monitor the Cowra Formation, which hosts the quarried sand

deposit. Hydraulic testing in the form of slug tests were carried out on these bores yielding hydraulic

conductivity values ranging from 3.4 to 10.4 m/day, which is four to five orders of magnitude greater than the

result yielded from the Cowra Formation well slug test during the DSI. The groundwater monitoring data

discussed in Hanson (2010) indicates that the baseline water table in the Cowra is at approximately 167 mAHD,

whilst the reported Murrumbidgee River gauge height is 168mAHD. This suggests groundwater surface water

interaction at that location, however pit dewatering by the quarry will shift the regime towards that of a losing

river since the base of the existing pit is at approximately 160 mAHD.

In the northern part of the Study Area it is considered that the degree of vertical connectivity within the alluvium

and surface water ground water interaction are considerably enhanced compared to the area around the Base

and Gumly Gumly Wetland. The major ion chemistry analysis presented in Section 12.2 also indicates some

groundwater surface interaction in the vicinity of the Murrumbidgee River.

13.2.4 Potential PFAS migration in groundwater

As described in Section 13.2.2 it is difficult to conceptualise a direct connection between the source zones and

the Lachlan Formation on the base due to the nature of the Cowra Formation. It is known that surface water

from the Base drains into the Gumly Gumly Wetland and PFAS has been detected in the stormwater drain. The

Murray Cod Hatchery bores show connectivity between the Lachlan and Cowra formations so on this basis one

possible pathway is an area of the wetland where vertical migration of surface water to the Lachlan formation is

permitted by the Cowra Formation. The groundwater abstraction from the Lachlan Formation at the hatchery

would enhance any downward leakage from the Cowra Formation and the hydrographs shown in Section

12.1.3 show that this abstraction has an influence on Lachlan Formation water levels at least 550 m away,

which would increase the downward pressure gradient from the Cowra Formation. The major ion chemistry

analysis presented in Section 12.2 shows that bores MW300 and MW312 exhibit water types that are closely

related to typical Cowra Formation water, which is consistent with enhanced vertical connectivity in the vicinity

of the Gumly Gumly Wetland.

This mechanism does not however explain the detections of PFAS in the Lachlan formation under the Base, in

particular the detection of 6:2FtS in MW306, which was designed as a control site located up gradient of the

source zones. Resampling of the Cowra and Lachlan Formation wells installed during the DSI found that PFAS

concentrations in all of the Base Lachlan Formation wells were below the laboratory LOR. Therefore, the initial

sampling results may have been associated with effects of the well installation activities. Further assessment of

potential PFAS migration pathways and the need for additional sampling will be carried out as part of the

HHERA.

13.3 Potential receptors and risk screening results

The potential receptors identified in the Preliminary CSM have been refined based on information obtained

during the DSI. The refined receptors and results of the Tier 1 risk screening process are presented in Table

13.2.

Table 13.2 : Summary of potential receptors, exposure mechanisms and risk screening results

Receptor Exposure mechanism Potential

unacceptable

risk?

Comments

On-Base receptors


IA147400-003-N-RPT-005 116


unacceptable

risk?

Comments

Construction and

maintenance workers

involved in sub-surface

works

Dermal contact with soil,

surface water or perched

groundwater.

Inhalation of dust particles.

Incidental ingestion of soil.

Yes PFAS was detected in soil, surface water and

perched groundwater. The PFAS NEMP guideline

values for human health do not consider potential

risks to these receptors. Further assessment would

be required for specific construction and

maintenance activities within the identified

significant source areas. This level of assessment is

outside the scope of the project.

Adults living or working on

Base

Dermal contact with soil or

surface water.



No No exceedance of the relevant PFAS NEMP

guideline values for human health in soil or surface

water.

Recreational adult users of

Base open space and

sporting facilities


surface water.


Incidental ingestion of soil


guideline values for human health in soil or surface

water.

Terrestrial ecology Direct exposure to soil

contamination

Yes Concentrations of PFOS in soil samples from PFAS

source areas exceeded the PFAS NEMP guideline

value for ecology – direct exposure.

Bioaccumulation and secondary

poisoning

Yes Concentrations of PFOS in soil exceeded the PFAS

NEMP guideline value for ecology – indirect

exposure.

Aquatic ecology Direct exposure to surface water

contamination

No PFAS concentrations in the surface water sample

from the dam in the south western corner of the

Base were below the PFS NEMP guideline value

for human health – recreational water use and the

PFAS NEMP guideline value for surface water –

freshwater aquatic ecology 95% species protection.


poisoning

Yes PFAS concentrations above the laboratory LOR

were identified in the surface water sample from the

dam in the south western corner of the Base.

Off-Base receptors

Construction and

maintenance workers

involved in sub-surface

works

Dermal contact with soil,

surface water or perched

groundwater.



Yes PFAS was detected in soil, surface water and

perched groundwater in off-Base locations. The

PFAS NEMP guideline values for human health do

not consider potential risks to these receptors.

Further assessment would be required for specific

construction and maintenance activities within the

impacted areas. This level of assessment is outside

the scope of the project.

Workers at Forest Hill STP Dermal contact with effluent

or treated effluent

Yes Sampling of treated effluent identified PFAS

concentrations exceeding the PFAS NEMP

guideline value for human health – recreational

water use.

General human receptors Dermal contact with soil.




guideline values for human health in soil.


IA147400-003-N-RPT-005 117


unacceptable

risk?

Comments

Dermal contact with surface

water

Incidental ingestion of

surface water

Yes PFAS concentrations in surface water samples from

the Gumly Gumly wetland and Marshalls Creek

drainage pathway exceed the PFAS NEMP

guideline values for human health – recreational

water use.

Consumption of

groundwater and surface

water abstracted for drinking

water

No Known groundwater bores used to supply drinking

water and the RWCC abstraction of surface water

from the Murrumbidgee River have all been tested

and found to have PFAS concentrations below the

laboratory LOR and the PFAS NEMP guideline

values for human health – drinking water.

Recreational use of

Murrumbidgee River

No PFAS concentrations in surface water samples in

the Murrumbidgee River were below the laboratory

LOR.

Consumption of fish and

shellfish from Murray Cod

Hatchery

Yes Elevated PFAS concentrations have been detected

in the surface water in the aquaculture ponds.

There is the potential for uptake of PFAS in the fish

and shellfish.

Consumption of fish and

shellfish from Murrumbidgee

River

Yes Elevated PFAS concentrations were identified in

surface water samples from Marshalls Creek

indicating potential discharge of PFAS to the

Murrumbidgee River. PFAS concentrations in

surface water samples from the Murrumbidgee

River were below the laboratory LOR. However,

there is the potential for PFAS uptake in fish and

shellfish at concentrations in surface water below

the LOR.

Consumption of shellfish

from farm dams

Yes Elevated PFAS concentrations were identified in

surface water samples from several farm dams

around the Base. PFAS uptake in shellfish may also

occur at concentrations in surface water below the

LOR.

Consumption of home

grown meat, eggs, fruit and

vegetables

No No current consumption of home grown produce in

PFAS impacted areas has been identified.

Concentrations of PFAS in soil from the vegetable

garden in the property adjacent to the Murray Cod

Hatchery were at or below the adopted screening

guideline values for residential with garden /

accessible soil.

Staff and recreational users

of Equex facility


surface water.


Incidental ingestion of soil

No Surface water samples in Marshalls Creek identified

a PFOS + PFHxS concentration above the PFAS

NEMP guideline value for human health –

recreational use. Water from Marshalls Creek is

used for irrigating playing fields at the centre. PFOS

+ PFHxS concentrations in soil samples collected at

the Equex facility were reported below the guideline

values for human health and ecological exposure

for public open space and parkland.

Livestock Consumption of pasture

material or vegetation and water

Yes PFAS was identified in several pasture or

vegetation samples accessible to livestock. Surface


IA147400-003-N-RPT-005 118


unacceptable

risk?

Comments

from farm dams or surface

water drainage

water sampling in a number of farm dams and

surface water bodies accessed by livestock

identified PFOS + PFHxS concentrations above the

PFAS NEMP guideline value for human health –

recreational use in the Gumly Gumly Wetland,

Marshalls Creek drainage pathway and in farm

dams close to the Base.

Terrestrial ecology Direct exposure to soil

contamination

No Concentrations of PFOS in soil samples from off-

Base areas were below the PFAS NEMP guideline

value for ecology – direct exposure.


poisoning

Yes Concentrations of PFOS in soil exceeded the PFAS

NEMP guideline value for ecology – indirect

exposure.

Aquatic ecology Direct exposure to surface water

contamination

Yes Concentrations of PFOS in surface water samples

in farm dams and the Marshalls Creek drainage

pathway exceeded the PFAS NEMP guideline value

for surface water – freshwater aquatic ecology 95%

species protection.


poisoning

Yes Concentrations of PFOS in Marshalls Creek

indicate a risk for bioaccumulation of PFAS in

aquatic biota. This bioaccumulation can also occur

at PFOS concentrations below the laboratory LOR.

Therefore, there is a risk for bioaccumulation in

aquatic biota in Kyeamba Creek and the

Murrumbidgee River.

The refined conceptual site model is presented graphically in Figure 43 and as an illustration in Figure 44.


IA147400-003-N-RPT-005 119

14. Data gaps and variability

14.1 Additional data required for the Human Health and Ecological Risk Assessment

The DSI has identified exceedances of adopted Tier 1 investigation criteria and the potential for several complete source, pathway, receptor relationships exists. Therefore, a site-specific HHERA to refine the likely degree of possible risk will be required. The following additional data will be required to support the risk assessment:

a) Sampling aquatic biota at the Murray Cod Hatchery in order to assess potential human health risks due to

consumption of the hatchery products as well as to assess potential ecological risks (bioaccumulation and

secondary poisoning)

b) Sampling of aquatic biota in the Murrumbidgee River to assess potential risks to human health through

consumption of fish or shellfish and to assess potential ecological risks (bioaccumulation and secondary

poisoning)

c) Sampling aquatic biota in Marshalls Creek and Kyeamba Creek to assess potential ecological risks

(bioaccumulation and secondary poisoning)

d) Sampling of yabbies’ in the farm dams surrounding the Base in order to assess potential human health

risks associated with consumption of the yabbies

e) Additional sampling of effluent at the Forest Hill STP to better understand PFAS contamination at the STP

and potential risks to workers as well as risks associated with the use of treated effluent

14.2 Potential variability

14.2.1 Surface water

Co-located surface water and sediment samples were collected in farm dams, in drainage channels and in

Gregadoo, Marshalls and Kyeamba Creeks. No rainfall had occurred in the 72 hours prior to sampling at many

of the locations. Water levels in several dams appeared to be below capacity and surrounding soil in the dam

indicated evaporation had occurred. Flow conditions in the drainage channels and creeks were generally

observed to be stagnant or low. These conditions are considered to represent typical surface water conditions

for the Study Area as significant rainfall events are infrequent. Elevated concentrations of PFAS are expected to

occur during these conditions as the process of evaporation is likely to concentrate PFAS in the remaining water

due to their low vapour pressure. Higher flow conditions in the drainage channels and creeks following rainfall

would likely result in dilution of PFAS concentrations.

As noted in Section 13.2.1, the Gregadoo Creek and Kyeamba Creek pathways do not appear to significant in

relation to the transport of PFAS from the Base. The reported PFAS concentrations are considered to represent

typical conditions. Results obtained from samples obtained during or post high rainfall would be highly diluted

and not representative, therefore, no further sampling is considered necessary. However, the Marshalls Creek

drainage pathway appears to be more significant and the collection of data on PFAS concentrations during

periods of higher flow may provide a more comprehensive assessment of potential PFAS impacts in this area.

One surface water sample (location SW218) was collected from the pipe that collects stormwater from the

southern portion of Forest Hill and discharges to the drainage channel that leads to Gumly Gumly wetland. This

includes drainage from the area around the NSW RFS station at Forest Hill. The sample was collected during a

dry period with low flow observed from the discharge point. While the reported concentrations of PFAS in the

sample were below the laboratory LOR, an additional sample during or shortly after a rainfall event is

recommended in order to further assess whether there is a source of PFAS at the RFS station contributing to

PFAS discharges to the wetland.

Water levels in the Murrumbidgee River are regulated through controlled discharges from Blowering Dam and

Burrinjuck Dam. As noted in Section 5.1, water levels are higher during the summer period in order to provide

sufficient water for downstream irrigators. Surface water and sediment samples collected from the

Murrumbidgee River during the DSI were collected during the summer (high flow) period and it is possible that


IA147400-003-N-RPT-005 120

PFAS concentrations may be more significant during lower flow conditions. Therefore, additional sampling in the

river during lower flow periods is recommended.

14.2.2 Groundwater

There are no environmental values associated with or beneficial uses of perched groundwater on Base and

sampling of this unit was primarily undertaken to assist in identifying and characterising sources of PFAS

contamination. While some variability of PFAS concentrations in perched groundwater may occur due to rainfall

infiltration, it is unlikely that this variability will influence risks or decision making.

Water level data from bores monitored by the Office of Water show that the typical annual variation in Lachlan

Formation groundwater levels within the previous three years is up to around three to five metres. These bores

are typically situated close to the Murrumbidgee River where a greater water level variation would be expected

compared to the area closer to the Base due to greater overall permeability of the alluvium and hence increased

rainfall recharge rates. As more water level data is collected during ongoing monitoring at bores installed as part

of the DSI at the Base and Gumly Gumly Wetland, longer term groundwater level variability will be identified and

discussed with respect to how groundwater level trends would affect groundwater movement and migration

pathways. Recommendations for further monitoring will be determined with consideration of these mechanisms.

The most significant driver in water level variability within the region is expected to be rainfall variation, both

seasonal and longer term cycles. However, groundwater levels will also be influenced by groundwater

abstraction and the Murrumbidgee River stage height where there is connectivity with the groundwater system.

PFAS concentrations above the laboratory LOR were detected in several of the new Cowra and Lachlan

Formation monitoring wells installed during the DSI. Collection of a second round of samples from these wells

was undertaken to assess potential variability introduced from bore installation and development (such as the

volume of water introduced during drilling), with results in all on Base wells reported as below the laboratory

LOR.

Sampling of the groundwater bores at the Murray Cod Hatchery and the RAAF Bore 5 monitoring well identified

significantly lower concentrations in the DSI sampling period (January and February 2018) than in the

preliminary sampling program (July 2017). This may be due to increased groundwater pumping during the

summer period.

The development of a groundwater model has been recommended as part of the HHERA. This will assist in

further refining the extent of PFAS impacts in groundwater and potential future risks. An assessment of potential

variability, data gaps and the need for any additional sampling or long term monitoring will be undertaken as

part of the HHERA and subsequent PFAS Management Area Plan.


IA147400-003-N-RPT-005 121

15. Conclusions and Recommendations

The DSI has identified three key PFAS source areas on the Base – the former Fire Training Area in the east of

the Airport, the current Fire Station and the Fire Extinguisher Concrete Pad and Former Fire Station area. The

concentrations of PFOS + PFHxS and PFOA in accessible soil in these areas were below the adopted

investigation criteria and, therefore, are not considered to present a risk to Base personnel. The leachable

concentrations indicate the potential for significant contribution of PFAS to surface water and groundwater from

these areas. A potential risk to terrestrial ecology on Base has also been identified.

The Cowra Formation on the Base was found to be dominated by dense high plasticity clays. Wells screened in

this formation only yielded groundwater at one location to the eastern side of this area. This geology is likely to

attenuate downwards PFAS migration to the lower Lachlan Formation which provides the main groundwater

source for the region. PFAS was detected in Lachlan Formation groundwater wells installed at the Base at

levels below adopted investigation criteria for drinking water during January 2018, however concentrations were

below the laboratory LOR when wells were resampled in April 2018. Additional sampling of these wells is

recommended to confirm the results and assess variability inherent in laboratory methods or variability that may

have been introduced by the well installation, development and sampling processes.

Stormwater from the majority of the Base (including the identified PFAS source areas) discharges to the Gumly

Gumly wetland and this was confirmed to be a significant pathway for PFAS transport. The Cowra Formation is

thinner in the wetland area and data collected from the Murray Cod Hatchery indicates there is vertical hydraulic

connectivity between the Cowra and Lachlan Formations in this area. Concentrations of PFOS + PFHxS in

groundwater at the Murray Cod Hatchery and in other properties adjacent to the Gumly Gumly wetland exceed

the adopted investigation criteria for drinking water.

Groundwater bores located further outside the wetland area had PFAS concentrations below the laboratory

LOR. Repeated sampling of the RWCC East Wagga Borefield and the Gumly Gumly Private Irrigation District

bore, have found that PFOS + PFHxS and PFOA concentrations are below the laboratory LOR. The exception

to this is that the Gumly Gumly Private Irrigation District bore was sampled on three occasions and on one occasion, the reported PFOS + PFHxS concentration was 0.03 µg/L, above the laboratory LOR but below the

adopted investigation criteria for drinking water of 0.07 µg/L.

While PFAS concentrations above the drinking water guideline value were also identified in a well located

approximately 400 meters east of the Base, this well is installed in the granite formation and it is difficult to

conceptualise a groundwater migration pathway from the Base to this well. The well has not been used for

many years and there are no other known users of groundwater in this area.

Therefore, based on the data collected to date and the refined conceptual site model, the extent of PFAS

contamination in groundwater exceeding the drinking water investigation criteria appears to be limited to the

Gumly Gumly wetland area and surrounding properties.

Further refinement of the current extent of groundwater contamination and potential future risks to downgradient

bores is recommended to be undertaken as part of the HHERA. A groundwater model is being established to

assist with this refinement.

Sampling of the Marshalls Creek drainage pathway indicates that this is a significant transport pathway for

PFAS contamination from the Gumly Gumly wetland. The concentration of PFOS in one surface water sample

from Marshalls Creek exceeded the investigation criteria ecological protection - freshwater aquatic ecology 95%

species protection. This indicates a risk to aquatic ecology in Marshalls Creek. Potential discharges of PFAS

from Marshalls Creek to the Murrumbidgee River may also present a risk to aquatic ecology in the river. The

Murrumbidgee River is used for recreational fishing and therefore the potential risk for bioaccumulation in fish

and shellfish and subsequent risk to human health will need to be assessed as part of the HHERA.

While PFAS was identified in surface water and sediment in farm dams immediately surrounding the Base, the

investigations indicate that the Gregadoo Creek and Kyeamba Creek drainage pathways do not appear to be

significant pathways for PFAS transport. It is understood that yabbies’ are collected for human consumption


IA147400-003-N-RPT-005 122

from some farm dams in the area and therefore an assessment of risks to human health will be undertaken as

part of the HHERA.

PFAS was identified in the effluent at the Forest Hill STP. Further sampling to better understand the source and

distribution of PFAS at the STP and an assessment of risks to STP workers as well as risks associated with the

use of treated effluent for irrigation will be undertaken as part of the HHERA.

The DSI has been completed in accordance with the NEPM and PFAS NEMP. Potential sources of PFAS

associated with use of AFFF at the Base were identified, investigated and characterised. PFAS transport

pathways are understood. The use of surface water and groundwater in the Study Area has been documented

and potential human health and ecological exposures have been identified. Therefore, the current extent of

PFAS contamination in terms of sources, pathways and receptors has been defined, satisfying the objectives of

the DSI. The data obtained from the DSI will now be used to inform the next stages of the broader investigation

program that will further refine understanding of risk and the management actions available to control

unacceptable risks.

The recommendations for the next stages of the project can be summarised as follows:

a) A Human Health and Ecological Risk Assessment (HHERA) will be undertaken to further assess risks

identified in this DSI. Targeted sampling will be required to obtain data to support the HHERA.

b) The HHERA will consider potential future risks to groundwater users downgradient of the Base. A

groundwater model is being developed to support this assessment. Survey of the Murray Cod Hatchery

bores and the RAAF Bore 5 monitoring well is recommended in order to better understand groundwater

elevations in these areas.

c) In addition to the sampling required to support the HHERA, the following sampling is recommended to

address potential variability identified in the DSI:

i. Sampling of the stormwater discharge from the area that includes the RFS station at Forest Hill during

or shortly after a rain event.

ii. Sampling of surface water in Marshalls Creek during or shortly following a rain event.

iii. Sampling of surface water and sediment in the Murrumbidgee River during the winter low flow period.

iv. Sampling of the well screened in the granite to the east of the Base (MW223).

d) A PFAS Management Area Plan will be developed as part of this Project and this will outline actions to

manage risks confirmed in the HHERA. This will include an Ongoing Monitoring Plan to monitor migration

of PFAS in the future. As noted above, the groundwater model will assist in identifying optimal locations for

the monitoring program and determining initial sampling frequencies based on potential variability.

e) Risks to workers involved in sub-surface construction or maintenance works will be highly dependent upon

the specific nature of the work and are outside the scope of this Project. However, the PFAS Management

Area Plan should include a requirement that a specific assessment of risks to these workers should be

undertaken prior to commencement of work in the identified PFAS source areas. This assessment should

also consider measures to ensure appropriate storage, handling and disposal of any PFAS impacted

materials.


IA147400-003-N-RPT-005 123

16. References

AECOM, 2013. RAAF Base Wagga Zone Plan, prepared for Department of Defence by AECOM dated 10 April,

2013.

ANZECC, 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, published by the

Australian and New Zealand Environment and Conservation Council and the Agriculture and Resource

Management Council of Australia and New Zealand dated October, 2000.

AS 4439.1–1999. Wastes, Sediments and Contaminated Soils – Preparation of Leachates, Preliminary

Assessment, published by Standards Australia dated 1999.

AS 4439.3–1997. Wastes, Sediments and Contaminated Soils – Preparation of Leachates, Bottle Leaching

Procedure, published by Standards Australia dated 1997.

AS4482.1 – 2005. Guide to the investigation and sampling of sites with potentially contaminated soil, Part 1:

Non-volatile and semi-volatile compounds, published by Standards Australia dated November, 2005.

AS/NZS 5667.11:1998. Water quality - Sampling - Guidance on sampling of groundwaters, published by

Standards Australia dated 1998.

Aurecon, 2009. Environmental Review of Fire Fighting Training and Facilities, Department of Defence, RAAF

Base Wagga - Site Report (Aurecon, 2009);

BoM, 2017a. Australian Groundwater Explorer. Produced by the Australian Government Bureau of Meteorology.

http://www.bom.gov.au/water/groundwater/explorer/map.shtml

BoM, 2017b. Australian Groundwater Dependent Ecosystem Atlas. Produced by the Australian Government

Bureau of Meteorology. http://www.bom.gov.au/water/groundwater/gde/map.shtml

Bouwer, H. and R.C. Rice, 1976. A slug test method for determining hydraulic conductivity of unconfined

aquifers with completely or partially penetrating bores, Water Resources Research, vol. 12, no. 3, pp. 423-428

Cardno, 2016a. Base Engineering Assessment Program, Part 4 Water Supply, Site: RAAF Base Wagga,

prepared for Defence by Cardno and KBR dated August 2016.

Cardno, 2016b. Base Engineering Assessment Program, Part 5 Wastewater, Site: RAAF Base Wagga,

prepared for Defence by Cardno and KBR dated July 2016.

Cardno, 2016c. Base Engineering Assessment Program, Part 6 Stormwater, Site: RAAF Base Wagga, prepared

for Defence by Cardno and KBR dated August 2016.

CERAR, 2004. Phase 1 and Phase 2 Proposal - Site Assessment of RAAF Base Wagga Wagga prepared by

CERAR, University of South Australia dated March 2004.

City of Wagga Wagga Council, n.d (a). Threatened species, populations and ecological communities found in

the Wagga Wagga Local Government Area, available on the City of Wagga Wagga Council website

http://www.wagga.nsw.gov.au/city-of-wagga-wagga/environment/biodiversity2

City of Wagga Wagga Council, n.d (b). Sewage Treatment information available on the City of Wagga Wagga

Council website http://www.wagga.nsw.gov.au/city-of-wagga-wagga/engineering-services/sewer/sewage-

treatment

Connell Wagner, 2008. RAAF Base Wagga Redevelopment Project - Requirements Analysis prepared for the

Department of Defence by Connell Wagner Pty Ltd dated 11 November 2008.

http://www.bom.gov.au/water/groundwater/explorer/map.shtml

http://www.bom.gov.au/water/groundwater/gde/map.shtml

http://www.wagga.nsw.gov.au/city-of-wagga-wagga/engineering-services/sewer/sewage-treatment

http://www.wagga.nsw.gov.au/city-of-wagga-wagga/engineering-services/sewer/sewage-treatment


IA147400-003-N-RPT-005 124

DEC, 2006. Guidelines for the NSW Site Auditor Scheme (2nd edition), published by the Department of

Environment and Conservation NSW dated April, 2006

Defence, 2012. Defence Contamination Directive (DCD) #7 Naming Convention – Surface Water, Groundwater

Well, Soil and Sediment Sampling Identification, Department of Defence, Defence Support Group, July 2012.

Defence, 2017a. Defence Contamination Directive (DCD) #8 (Amendment 2) Screening Guidelines, Department

of Defence Estate and Infrastructure Group, May 2017.

Defence, 2017b. Guidance Document F, Development of Investigation Areas for PFAS Detailed Site

Investigation, published by Department of Defence, correct as at 2 June 2017.

Defence, 2107c. Guidance Document E, published by Department of Defence, correct as at 10 July, 2017.

Defence, 2017d. PFAS Investigation and Management Detailed Site Investigation Guidance Document D – Non

PFAS Analysis of Other Chemicals of Potential Concern, published by Department of Defence dated June,

2017.

Defence, n.d. File titled “RAAF Wagga - site drawing - trg areas where AFFF was deployed and trg pad

seperator pits”, site plan for RAAF Base Wagga with mark-up of areas of “foam usage in the past”, not dated.

Department of Environment and Energy, 2016. Commonwealth Environmental Management Guidance on

Perfluorooctane Sulfonic Acid (PFOS) and Pefluorooctonoic Acid (PFOA), published by the Department of

Environment and Energy (Commonwealth) draft dated October, 2016.

Department of Health, 2017. Final Health Based Guidance Values for PFAS For Use in Site Investigations In

Australia, issued by Department of Health (Commonwealth), 2017.

DLWC, 1996. Bore Construction Details for Bore GW39573, prepared by DLWC dated 14 August, 1996.

enHealth, 2016. enHealth Guidance Statements on per- and poly-fluoroalkyl substances, Environmental Health

Standing Committee (enHealth) of the Australian Health Protection Principal Committee, June, 2016.

EarthTech, 2005. Stage 1 Contamination Investigation of RAAF Base Wagga Wagga prepared by EarthTech

Engineering, 2005.

Environmental & Earth Sciences, 1996. Assessment and Audit of Forest Hill Waste Disposal Facilities, prepared

by Environmental & Earth Sciences Pty Ltd for Wagga Wagga City Council dated 14 May 1996

Environmental & Earth Sciences, 1997. Annual Review – Groundwater Monitoring at the Former Forest Hill

Waste Disposal Facility, Wagga Wagga, NSW, prepared by Environmental & Earth Sciences Pty Ltd for the

Council of the City of Wagga Wagga dated 24 September, 1997.

Environmental & Earth Sciences, 2004. Groundwater monitoring at the former Forest Hill Waste Disposal

Facility, Wagga Wagga, New South Wales, prepared by Environmental & Earth Sciences NSW for the Council

of the City of Wagga Wagga dated December, 2004.

EPA, 2015. EPA South Australia Environmental Information. Date accessed 16 June

2017.http://www.epa.sa.gov.au/environmental_info/water_quality/threats/salinity

FSANZ, 2017. Perfluorinated Chemicals in Food, published by the Food Standards Authority of Australia and

New Zealand, 2017.

GHD, 2004. Forest Hill Civilian and RAAF Airport Complex, Emergency Stormwater Management Plan,

prepared by GHD Pty Ltd for City of Wagga Wagga Council dated 2004. Note: Appendix A not available.


IA147400-003-N-RPT-005 125

GHD, 2016. Defence per- and poly-fluoroalkyl Substances (PFAS), Environmental Management Preliminary

Sampling Program, RAAF Base Wagga, Final Report, prepared for Jones Lang LaSalle by GHD dated

September, 2016.

Golder Associates, 2012a. RAAF Base Wagga Stage 1 Environmental Investigation. Report Number

117623117-R-006-Rev0 dated May 2012.

Golder Associates, 2012b. RAAF Base Wagga Stage 2 Environmental Investigation. Report Number

117623117-017-RBW dated 5 October 2012.

Hanson, 2010. Environmental Assessment Report Sand and Gravel Quarry Extension Wagga Wagga NSW

Volume 1. Dated April 2010

HEPA, 2018. PFAS National Environmental Management Plan, published by the Heads of EPAs Australia and

New Zealand dated January 2018.

HLA, 2002. Water Balance Study, Riverina Murray Valley. Final Report. Produced by HLA Envirosciences Pty

Limited. Document ref: D0244. Dated 16 October 2002.

HLA, 2003. Heritage Assessment, RAAF Base Wagga Wagga prepared for Department of Defence by HLA

Envirosciences dated 4 April 2003.

Hvorslev, M.J., 1951. Time Lag and Soil Permeability in Ground-Water Observations, Bull. No. 36, Waterways

Exper. Sta. Corps of Engrs, U.S. Army, Vicksburg, Mississippi, pp. 1-50

Jacobs, 2017a. Comprehensive PFAS Investigations at RAAF Base Wagga, Preliminary Conceptual Site

Model, prepared by Jacobs Group (Australia) Pty Ltd for the Department of Defence dated November, 2017.

Jacobs, 2017b. Comprehensive PFAS Investigations at RAAF Base Wagga, Preliminary Sampling Report,

prepared by Jacobs Group (Australia) Pty Ltd for the Department of Defence dated July, 2017.

Jacobs, 2017c. Comprehensive PFAS Investigations at RAAF Base Wagga, Investigation Derived Wastewater

Management Strategy, prepared by Jacobs Group (Australia) Pty Ltd for the Department of Defence dated

November, 2017.

Jacobs, 2017d. Comprehensive PFAS Investigations at RAAF Base Wagga, Sampling, Analysis and Quality

Plan, prepared for the Department of Defence by Jacobs Group (Australia) Pty Ltd dated 24 November 2017.

Maunsell Australia Pty Ltd / CH2M Hill Australia Pty Ltd / AECOM. July 2006. RAAF Base Wagga Wagga

Stage 2 Environmental Investigation Final Report. (Maunsell, 2006)

Mitchell, M., 2009, Mid Murrumbidgee Alluvium. Groundwater Management Area 013: Gundagai to Narrandera.

Groundwater Resources Status Report – 2007, NSW Department of Water and Energy, Sydney

OEH, 2011. Guidelines for Consultants Reporting on Contaminated Sites published by the NSW Office of

Environment and Heritage, 2011

OEH Science, 2017. PFAS Screening Criteria (May 2017) (Draft), prepared for the NSW EPA by the Office of

Environment and Heritage Science dated May, 2017.

Office of Water, 2018. Stream height data for the Murrumbidgee River at Wagga and Kyeamba Creek at

Ladysmith Obtained from the following website by Jacobs on 29 May 2018 -

http://realtimedata.water.nsw.gov.au/water.stm

O’Neil, 2007. Mid Murrumbidgee Zone 2 Groundwater Flow Model. Model Development and Calibration Final

Draft. Produced for the water Management Division, NSW Department of Water and Energy. Dated October

2007.


IA147400-003-N-RPT-005 126

National Uniform Drillers Licensing Committee 2013. Minimum construction requirements for water bores in

Australia.

NEPC, 2013. National Environment Protection (Assessment of Site Contamination) Measure 1999 as amended

2013 published by the National Environment Protection Council dated 11 April, 2013.

NSW DEC, 2007. Contaminated sites: Guidelines for the assessment and management of groundwater

contamination. Sydney, N.S.W.: NSW Department of Environment and Conservation.

NSW EPA, 2011. Contaminated sites: Guidelines for consultants reporting on contaminated sites. Chatswood,

N.S.W.: NSW Environment Protection Authority.

NSW EPA, 2014. Waste Classification Guidelines Part 1: Classifying waste, published by the NSW Environment

Protection Authority dated November, 2014.

NSW EPA, 2015. Guidelines on the duty to Report Contamination under the Contaminated Land Management

Act 1997. Sydney, N.S.W.: Environment Protection Authority.

NSW EPA, October 2016. Addendum to the Waste Classification Guidelines (2014) – Part 1: classifying waste,

published by the NSW Environment Protection Authority dated October, 2016.

NSW EPA, November, 2016. Designing Sampling Programs for Sites Potentially Contaminated by PFAS,

Guidance Document, published by the NSW Environment Protection Authority dated November, 2016.

NSW EPA, 2017. Contaminated Land Management: Guidelines for the NSW Site Auditor Scheme (3nd ed.).

Sydney, N.S.W.: NSW Environment Protection Authority.

Raymond, O.L, 1993. Geology of Wagga Wagga and the Kyeamba Valley. Scale 1:100,000. Published by the

Australian Geological Survey Organisation, Department of Primary Industries and Energy.

US DoD/DoE, 2017. Consolidated Quality Systems Manual (QSM) for Environmental Laboratories Version 5.1,

published by the United States Department of Defence and the United States Department of Energy dated

2017.

US EPA, 2015. ProUCL Version 5.1 User Guide, published by the United States Environmental Protection

Agency dated October 2015.

US EPA 537. Determination of Selected Perfluorinated Alkyl Acids in Drinking Water by Solid Phase Extraction

and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS), published by the United States

Environmental Protection Agency dated September, 2009.

US EPA 821-R-11-007. Draft Procedure for Analysis of Perfluorinated Carboxylic Acids and Sulfonic Acids in

Sewage Sludge and Biosolids by HPLC/MS/MS, published by the United States Environmental Protection

Agency dated December, 2011.

Van der Kamp, Garth, 1976, Determining aquifer transmissivity by means of bore response tests: the

underdamped case: Water Resources Research, v. 12(1), 71–77 p.

Vantage, 2009. Identification of Priority Pollutants, Site No. 0906, RAAF Base Wagga prepared by Vantage

Environmental Management, 2009.

WA DER, 2017. Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl

Substances (PFAS), Contaminated Sites Guidelines, published by the Western Australia Department of

Environmental Regulation dated January, 2017.

Weight, W., 2008. Hydrogeology Field Manual. 2nd ed. New York: McGraw Hill

comprehensive investigation of per- and poly- fluoroalkyl … · 2020. 12. 9. · detailed site...

Documents