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Cooperative Research Centre for Contamination Assessment and Remediation of the Environment
Assessment, management and remediation for PFOS and PFOAPart 4: application of HSLs and ESLs
TEcHnicAL REPORT nO. 38
Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Technical Report series, no. 38 January 2017 Copyright CRC CARE Pty Ltd, 2017 This book is copyright. Except as permitted under the Australian Copyright Act 1968 (Commonwealth) and subsequent amendments, no part of this publication may be reproduced, stored or transmitted in any form or by any means, electronic or otherwise, without the specific written permission of the copyright owner. ISBN: 978-1-921431-56-2
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This report should be cited as: CRC CARE 2017, Assessment, management and remediation guidance for perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) Part 4: application of HSLs and ESLs, CRC CARE Technical Report no. 38, CRC for Contamination Assessment and Remediation of the Environment, Newcastle, Australia.
Disclaimer: This publication is provided for the purpose of disseminating information relating to scientific and technical matters. Participating organisations of CRC CARE do not accept liability for any loss and/or damage, including financial loss, resulting from the reliance upon any information, advice or recommendations contained in this publication. The contents of this publication should not necessarily be taken to represent the views of the participating organisations.
CRC for Contamination Assessment and Remediation of the Environment
Technical Report no. 38d
Assessment, management and remediation guidance
for perfluorooctanesulfonate (PFOS) and
perfluorooctanoic acid (PFOA)
Part 4 application of HSLs and ESLs
CRC CARE Technical Report no. 38d i
Assessment, management and remediation guidance for PFOS and PFOA. Part 4 appliation of HSLs and ESLs
Important note to readers
This guidance is to be regarded as both draft and interim, particularly in relation to
health based screening values.
The following caveats and limitations apply to this guidance:
the health based values in this guidance are based on the interim TDI values
endorsed by enHealth in 2016 for PFOS (+PFHxS) and PFOA, and
should revised TDI values be endorsed by enHealth or another major national
health based agency in Australia, then the health derived values in this guidance
will be updated accordingly, and the guidance re-issued.
It is recognised that there is much on-going research on the impacts of PFOS and
PFOA on human health and the environment, the outcomes of which may improve the
assessment, remediation and management of PFOS and PFOA. These developments
will be monitored and this guidance will be updated, as appropriate.
It is also recognised that PFAS compounds other than PFOS and PFOA may
contribute to the impacts of PFAS on human health and the environment. When further
research results for other PFAS compounds (or classes thereof) of sufficient
robustness to be utilised in the formulation of guidance for those compounds (or
classes thereof) become available, then that information will be used to extend the
scope of this guidance.
This guidance should therefore be regarded as both draft and interim.
CRC CARE Technical Report no. 38d ii
Assessment, management and remediation guidance for PFOS and PFOA. Part 4 appliation of HSLs and ESLs
CRC CARE has milestones in its Agreement with the Commonwealth Government
relating to the development of guidance for contaminants of emerging concern in
collaboration with end users. Priority contaminants were identified for CRC CARE
through regulators and end users who met at a Forum held in February 2012. These
contaminants included perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid
(PFOA), which belong to a large group of compounds called per- and polyfluoroalkyl
substances (PFAS). CRC CARE has undertaken the development of human health
screening levels (HSLs) and ecological screening levels (ESLs) for PFOS and PFOA;
these values provide a collective view of the available science and application of
Australian approaches on the development of human health and ecological based
The derivation of the HSLs and ESLs has followed the methodologies outlined in the
National Environment Protection (Assessment of Site Contamination) Measure 1999
(NEPM), as revised in 2013. HSLs and ESLs are subject to the assumptions,
uncertainties and limitations outlined in the relevant parts of the guidance deviations
from the assumptions used in their derivation may mean that a site specific
assessment would be required. Further, HSLs for some exposures are calculated using
a 100% relative source contribution. If more than one of these sources is relevant, use
of the screening values would underestimate risks, and in this case, cumulative
assessment of all relevant exposures must be made.
The NEPM emphasises the importance of formulating a conceptual site model on
which to base the assessment of soil and groundwater contamination, and guidance
has been provided on the development of a conceptual site model for PFOS
It is intended that the HSLs and ESLs that have been developed for PFOS and PFOA
should be considered similarly to the NEPM HILs/HSLs and EILs/ESLs in forming
generic screening levels which, if exceeded, would indicate that further more detailed
investigation is required. The HSLs and ESLs and the information used in their
derivation can assist in undertaking this more detailed investigation.
It is emphasised that exceedance of the HSLs and ESLs does not necessarily imply
that the contamination poses an unacceptable risk, and the HSLs and ESLs should not
be used as remediation targets, as this could result in unnecessary remediation.
The following limitations should be noted:
The assessment and management of PFAS contamination in soil and groundwater
is an emerging science in Australia and internationally and significant work
continues to be undertaken. It is recommended that when using this guideline,
more recent information is considered.
Uncertainties and limitations in the guidance values and their application are noted
in the guidance document, and these should be considered when using the values.
Some of the screening levels have assumed the occurrence of bioaccumulation
and biomagnification based on international work - there is uncertainty as to the
levels that will occur in Australian organisms. Where significant exceedances of
HSLs and ESLs occur, consideration should be given to direct monitoring of
CRC CARE Technical Report no. 38d iii
Assessment, management and remediation guidance for PFOS and PFOA. Part 4 appliation of HSLs and ESLs
potentially affected organisms to determine if there are effects that can be
distinguished. Further assessment would be would be required where
bioaccumulation is an issue.
This review has focussed on PFOS and PFOA. PFAS include a large number of
compounds and analytical methods are reporting an increasing number of PFAS
compounds. As this guidance document was being finalised, enHealth (2016) has
advised that perfluorohexane sulfonate (PFHxS) should be considered to be
additive to PFOS, The use of the HSLs and ESLs for PFOS and PFOA should
recognise that other PFAS may contribute to potential effects and where present,
these will need to be evaluated for potential cumulative risks in accordance with
Because of the evolving nature of the science relating to PFAS, these guidelines are
considered to be Interim Guidance, and it is recommended that a review of this
guidance is considered following any change in recommendation by enHealth or
This guidance is intended for a variety of users within the contaminated sites industry,
including site owners, proponents of works, contaminated land professionals, and
regulators. It is assumed that readers are familiar with the NEPM 2013. While the aim
of this guideline is to provide a resource that can be used at PFAS-contaminated sites
across Australia, it does not replace specific laws, regulations and guidance provided
at a local level.
CRC CARE Technical Report no. 38d iv
CSM Conceptual site model
CRC CARE Cooperative Research Centre for Contamination
Assessment and Remediation of the Environment
ESL Ecological screening levels
HSL Health screening levels
NEPM National Environment Protection (Assessment of Site
Contamination) Measure 1999, as revised in 2013
PFAS Per- and polyfluoroalkyl substances
PFHxS perfluorohexane sulfonate
PFOA Perfluorooctanoic acid
PFOS Perfluorooctane sulfonate
CRC CARE Technical Report no. 38d v
Table of contents
Executive summary i
1. Introduction 1
1.1 Framework for assessing contaminated sites 2
1.2 Site investigation 2
1.3 Sampling and analytical methods and considerations 2
1.3.1 Sample collection 2
1.3.2 Laboratory analysis of soil and water samples 3
1.4 Developing the conceptual site model 4
2. Health screening level (HSLs) 8
2.1 Soil HSLs 8
2.2 Groundwater HSLs 9
2.3 Water and sediment (human consumption of seafood) HSLs 11
2.3.1 Multiple pathway exposure and cumulative risk 12
3. Ecological screening levels (ESLs) 13
3.1 Freshwater ecosystem ESLs 13
3.2 Marine ecosystem ESLs 13
3.3 Terrestrial ecosystem ESLs 13
3.4 Considerations in the application of ESLs 14
4. References 16
CRC CARE Technical Report no. 38d vi
Table 1. Summary of soil HSLs for PFOS and PFOA (mg/kg) 8
Table 2. Considerations in the application of soil HSLs 9
Table 3. Summary of groundwater HSLs for PFOS and PFOA 10
Table 4. Considerations in the application of groundwater HSLs for
PFOS and PFOA
Table 5. Summary of derived surface water and sediment HSLs for
PFOS and PFOA
Table 6. Considerations in application of surface water and sediment
consumption of fish HSLs for PFOS and PFOA
Table 7. Default guidelines for PFOS and PFOA 13
Table 8. Marine ESLs for fresh PFOS and PFOA 13
Table 9. ESLs values for fresh PFOS and PFOA in soils 13
Table 10. Considerations in the application of ESLs 14
Figure 1. Inputs to a site specific CSM 6
Figure 2. Example CSM for PFAS-contaminated media 7
CRC CARE Technical Report no. 38d 1
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been
identified as contaminants of emerging concern in Australia. These contaminants
belong to the broad group of chemicals referred to as per- and poly-fluoroalkyl
PFAS are highly persistent and potentially toxic to humans and the environment, and
some are bioaccumulative. PFOS and PFOA are considered to be the most widely
studied of the PFAS due to historical production and in terms of breakdown of
precursor compounds. PFAS have been detected at concentrations of potential
concern at a number of sites, particularly where there has been use of firefighting
foams. Industry and public awareness of the presence of PFOS and PFOA, is growing
rapidly. Reporting of PFOS contamination problems in the media has raised particular
concern regarding the risk that the contamination poses to the health of exposed
persons and the environment.
In general, there is limited information on the occurrence, fate and toxicity of PFAS in
the Australian environment. Australian screening levels for protecting human health
and ecological systems are needed to assess the level of risk that the contamination
The Cooperative Research Centre for Contamination Assessment and Remediation of
the Environment (CRC CARE) has developed human health and ecological screening
levels (HSLs and ESLs) for PFOS and PFOA in soil, marine waters, groundwater and
sediment, following the approach provided in the National Environment Protection
(Assessment of Site Contamination) Measure 1999, as amended in 2013 (NEPM)
(NEPC, 2013) and Australian Drinking Water Guidelines (NHMRC 2011), and provides
information on the application of these screening levels. This guidance provides a
practicable approach to the risk-based assessment, management and remediation of
PFAS contamination. It comprises five stand-alone sections:
Part 1: Background
Part 2: Human health screening levels
Part 3: Ecological screening levels
Part 4: Application of human health and ecological screening levels (this
Part 5: Risk based management and remediation of PFOS and PFOA
This section, part 4, is an application document which provides a summary of the HSLs
and ESLs, and considerations on how to apply them in the assessment of PFOS and
PFOA contaminated soils, sediments and waters. It is strongly recommended that
part 4 is read in conjunction with part 2 and part 3 of the guidance document, as these
sections provide the background information, rationale and derivation of the screening
CRC CARE Technical Report no. 38d 2
1.1 Framework for assessing contaminated sites
The process for the assessment of PFAS-contaminated sites should follow that
outlined in the NEPM, which is recognised as the primary national guidance document
for the assessment of site contamination in Australia.
The NEPM includes two schedules:
Schedule A provides a general process for assessment of site contamination, and
Schedule B of the NEPM comprises 10 technical guidelines about site
assessment, screening levels, site investigations, laboratory analyses, human
health and ecological risk assessment, groundwater assessment, community
consultation, consultants and auditors, and health and safety.
Schedule A is of particular importance when making decisions as to the appropriate
investigation and management of PFAS-contaminated sites. It is important this work is
conducted by persons with a thorough understanding of contaminated site assessment
and management, particularly with respect to PFAS.
1.2 Site investigation
The first step towards developing a management strategy for a PFAS-contaminated
site is in understanding the extent and magnitude of contamination, and is a key step in
Soil, sediment, surface water or groundwater sampling (as appropriate) and laboratory
analysis is essential in delineating the extent and magnitude of the problem, and hence
associated risks. As far as is practicable, sampling should be representative of the
system being investigated. Sampling is likely to be an iterative process, commencing
with a high level, preliminary sampling program and becoming more specific as the
extent and magnitude of contamination is better understood.
Schedule B2 of the NEPM provides detailed information on the design and
implementation of a sampling and analysis plan.
1.3 Sampling and analytical methods and considerations
1.3.1 Sample collection
Because of the unique chemical properties of PFOS and PFOA, consideration must be
given to the low flow groundwater sampling setups which has been shown to leach
long chain PFAS can adsorb to the surfaces of sample equipment (CONCAWE 2016).
Additionally, it is recommended that Teflon-containing materials are avoided as a
precautionary measure (ALS 2013, CONCAWE 2016). The implications of using
Teflon-containing materials during sampling warrants further investigation, as it is
currently unclear the extent to which, if any, cross contamination may occur. The effect
of leaching from sampling materials or sample storage vessels on sample
concentrations can become particularly important when working at the very low
concentrations indicated by the fresh water ESLs and HSLs.
CRC CARE Technical Report no. 38d 3
With respect to groundwater samples, if these are not filtered (investigation wells tend
to draw in more sediments than wells constructed for other uses), consideration should
be given to the sediment load in the sample and the possible effect on the measured
PFOS and PFOA concentrations, as significant PFOS and PFOA may have adsorbed
to the sediment material. It is important to take into consideration the quality of the
water to which the receptor would actually be exposed.
It may be useful to also include any supplementary information that could assist in
understanding transformation rates of precursors to PFOS and PFOA, if possible (e.g.
anaerobic/aerobic conditions may be a factor however the extent to which they affect
transformation in real conditions is less understood at this time (Houtz et al. 2013).
International studies have found some success with passive sampling of PFAS in water
using a modified polar organic chemical integrative sampler (POCIS), although uptake
and hence the reported concentration can be affected by water flow rate
(Karsenzon et al. 2013). Passive sampling has not yet been widely implemented in
1.3.2 Laboratory analysis of soil and water samples
Internationally there are a range of standard methods utilised for the analysis of PFAS,
mostly based on liquid chromatography with a tandem MS/MS detector
The National Measurement Institute (NMI) conducted a pilot proficiency study in 2015
to compare the performances of 11 laboratories, evaluate their test methods, and
assess their accuracy in measuring total and linear PFOS and PFOA in soil and water
matrices. Nine of the laboratories used a detection method of LC-MS/MS, but a variety
of extraction methods were adopted. There was no correlation found between results
and method. Results varied between individual samples, and between laboratories. A
spiked water sample with a PFOS concentration of 3.2 g/L resulted in a maximum
concentration detected of 5.7 g/L and a minimum concentration of 2.3 g/L. The
results of a water sample spiked with 3.7 g/L of PFOA resulted in a maximum
concentration detected of 8.7 g/L and a minimum concentration of 3.4 g/L. Water
was sampled from a contaminated site and the results for the PFOS concentration
were reported ranging from 0.001 to 0.0031 g/L and PFOA from 0.0036 to 0.0040
g/L with some laboratories reporting non detected with a detection limit of 1 g/L.
Spiked soil concentrations also showed variability, with soil spiked with 8.6 g/kg PFOS
showing a range of 5 to 18 g/kg and soil spiked with 251 g/kg PFOS showing a
range of 163 to 352 g/kg. Soil spiked with PFOA also showed a similar range of
detections with a spike of 8.9 g/kg recorded from 5.4 to 20 g/kg (NMI 2015).
Laboratories were requested to report a measure of uncertainty for results, which
ranged between 0.9% and 100% of the reported value (NMI 2015).
From this it is evident there is variability in the analytical results reported for PFOS and
PFOA within, and between laboratories in Australia. NMI noted, however, that the
performance of laboratories was similar to that observed in other NMI pilot trials for
organic pollutants1. It has been hypothesised that the variability observed in PFOS
results may in part be due to some laboratories using linear standards, and others
using mixed standards (i.e. linear and branched) for PFOS (ALS 2015). This is being
1 End user discussion, held by NMI across Australia on 14 August 2015
CRC CARE Technical Report no. 38d 4
further investigated, and NMI has recommended further studies. The variability could
also in part be due to the low levels being analysed.
A second proficiency testing study on the analysis of PFOS and PFOA in soil, water
and fish was conducted in June 2016 with 26 laboratories (NMI 2016). The data from
both proficiency testing studies show a wide variety of results for the same sample,
therefore it is important to understand what is being reported. The 2016 participants
reported up to 72% of the reported value. A variety of methods for extraction were
used, with no correlation between results and method the analytical detection method
used was LCMS/MS.
The results reported by different laboratories also showed a variety of detection limits,
particularly with the water samples. In many cases the detection limits were above
drinking water/groundwater guidelines commonly used at the time of testing. When
detection limits exceed screening levels it is necessary to err on the side of caution and
assume the screening level is exceeded, thus resulting in the requirement of
management actions when they may not be necessary. For example, the typical
detection limit for PFOS in water can be 100 ng/L, which is greater than the
concentration of interest when evaluating fish uptake and suitability for human
consumption. In such a situation requesting a trace method of analysis may be able to
reduce the detection limit to less than 1 ng/L (perhaps to 0.2 ng/L). Therefore, when
requesting analysis of PFOS and PFOA in soil and water the following should be
included on the chain of custody form:
Request for the uncertainty estimate (if this is not requested the laboratory is not
required to provide it)
Request that the method of analysis is reported for ease of comparison of results,
Request an appropriate detection limit that will allow the sample to be compared to
With respect to interpreting laboratory analytical results for PFOS and PFOA-
contaminated soil, sediment and water samples, it is important to be aware of the
possible uncertainty range in results reported, particularly when concentrations are
reported of similar magnitude to the HSLs or ESLs. Undertaking sufficient quality
assurance/quality control sampling, such as collection of samples for interlaboratory
analysis is important in evaluating the accuracy of analytical results.
1.4 Developing the conceptual site model
Schedule B2 of the NEPM provides information on the development of a conceptual
site model (CSM). Development of a site-specific CSM is an iterative process, with the
complexity of the CSM corresponding to the scale and complexity of the known or
potential impacts. As more information is gathered about a site and the contamination,
the CSM can be further refined to allow remediation and management actions to be
defined that are commensurate with the scale of the problem and are most cost
The essential elements of a CSM are outlined in section 4.3 of Schedule B2 of the
NEPM. Briefly these include:
CRC CARE Technical Report no. 38d 5
Known and potential sources of contamination and contaminants of concern and
precursors, including the mechanism of contamination (e.g. surface spill top down
which is most commonly the case for PFAS-contaminated sites, or a subsurface
release such as from a corroded pipe).
The media contaminated (e.g. soil, groundwater, surface water, sediments, and
Potential human and ecological receptors, such as site works or the general public,
users of groundwater at or removed from the site, and terrestrial and surface water
Potential exposure pathways, how humans or ecological receptors may become
exposed to PFAS (e.g. direct contact through handling contaminated soil, ingestion
of contaminated soil/dust, surface water runoff or contaminated groundwater
discharge to surface water bodies). Once current and potential future exposure
pathways have been identified it needs to be determined whether the pathways
are complete (refer to NEPM schedule B6). If a pathway is incomplete the risk to
receptors may be low despite the presence of contamination.
In developing and refining the CSM it is important to ensure that the available data are
representative (i.e. provides an accurate picture of the contamination, without biasing
high or low), and to understand where variability and uncertainty may lie (is the extent
and magnitude of contamination sufficiently well defined), and the significance of data
Further detail regarding aspects to be considered when developing a site-specific CSM
for PFOS- and PFOA- contaminated sites is provided in part 1 and part 5 of this
guidance document. A brief summary of aspects to consider is provided in figure 1, and
an example CSM is provided in figure 2.
Because of the persistence and bioaccumulative properties of PFOS and PFOA, the
CSM will need to consider scenarios and pathways that may not be normally
considered for other contaminants. Example pathways that may need to be examined
Leaching from soil to groundwater
Groundwater discharge into surface water bodies
Adsorption onto and leaching from sediments
Bioaccumulation/biomagnification through the food chain, particularly in seafood
Discharge to the sewerage system, with potential for accumulation in biosolids and
discharge in the treated effluent
Irrigation with uptake by plants, and possible accumulation in soil
Ingestion of contaminated plant material and soil by livestock during grazing
Uptake by garden produce and ingestion by persons or animals
Consumption by persons of meat and animal products (e.g. milk and eggs), and
Consumption of breast milk by infants.
This list is by no means exhaustive, and each site will need to be evaluated on a case
by case basis. A discussion on how these aspects should be considered in the
application of the HSLs and ESLs is provided in section 2 and section 3 respectively.
Further detail is provided in part 2 and part 3 of the guidance.
CRC CARE Technical Report no. 38d 6
Figure 1 Inputs to a site specific CSM
CRC CARE Technical Report no. 38d 7
Figure 2 Example CSM for PFAS-contaminated media
CRC CARE Technical Report no. 38d 8
2. Health screening level (HSLs)
The background information and derivation of HSLs is provided in part 2 of this
guidance document. This section provides a brief summary of the land and
groundwater use scenarios, potential receptors, and the HSLs. The limitations of the
HSLs and receptor populations for which HSLs have not been developed but that
require consideration are also discussed. For a discussion about the derivation and
limitations of these screening levels, refer to part 2.
2.1 Soil HSLs
Consistent with the NEPM, HSLs have been developed for four land use scenarios,
summarised in table 1.
Table 1 Summary of soil HSLs for PFOS and PFOA (mg/kg)
Land use PFOS
Low density residential (HSL-A) Residential scenario with garden/accessible soil (home-grown produce
CRC CARE Technical Report no. 38d 9
Table 2 Considerations in the application of soil HSLs
Consumption of home grown garden produce
Although the uptake of PFOS and PFOA by garden produce may occur, and be significant, it is difficult to derive a generalised screening criterion. The likelihood of this exposure pathway should be reviewed on a site-specific basis, and direct sampling of plants may be required.
Protection of groundwater/surface water quality
Leaching of PFOS and PFOA from contaminated soils to groundwater systems frequently occurs. The soil HSLs do not account for the leaching potential of PFOS and PFOA, as attempting to predict the groundwater concentrations that will arise from soil contamination is highly complex and site specific. Where groundwater contamination has occurred, direct measure of groundwater concentrations should be undertaken, and compared against the relevant groundwater HSLs. Additionally, leaching potential of PFAS from soil samples may be tested using the Australian Standard Leaching Procedure (ASLP) test (Australian Standard 4439). This test measures how much of a chemical can move from soil into water using conditions similar to rain events. Other types of leaching tests are available which are designed to be used to evaluate leaching in landfills under more extreme conditions and are less relevant for the initial screening of these sites. The trigger points in leachate as measured in an ASLP test should consider the dilution that will occur as the leachate moves from the soil into the underlying groundwater; this will depend on the relative rates of rainfall and groundwater movement, absorption in the soil, local concentration in groundwater, and the depth of groundwater into which the leachate mixes. Note US EPA recommend a default factor of 20. (Reference should be made to the relevant jurisdiction which may have specific requirements for the protection of groundwater/surface water quality)
Sensitive receptors in commercial properties
For commercial properties an adult worker has been identified as the primary receptor. It is assumed that the public, including children would visit commercial properties for short periods only, and hence the risk to the public would be less than for workers present at the site on a full-time basis. The commercial/industrial HSLs may not adequately protective of more sensitive land uses that may be permissible under commercial/industrial zoning in some jurisdictions (e.g. schools, childcare centres, health care facilities, nursing homes, hospitals). If such developments are present or proposed, consideration should be given to more conservative screening levels (i.e. HSL-A) or a site-specific risk assessment. Occupational exposures may be best addressed separately.
Open grounds Given that PFAS chemicals are non-volatile, exposure is limited to direct contact with soil contamination. Vapour intrusion is not a significant factor in exposure and therefore the presence of buildings is not a limitation in the use of industrial/commercial HSLs. Industrial properties such as fire training grounds should still be based on commercial/industrial screening levels (HSL-D) provided access by the general public is prohibited.
Agriculture and grazing
A site specific assessment may be required which could include sampling of crops and biota.
2.2 Groundwater HSLs
Potential beneficial uses of groundwater and HSLs (where derived) are provided in
table 3, and considerations for their application are detailed in table 4. Note the
relevant beneficial uses of groundwater that require consideration differs between
jurisdictions and local regulations and guidelines should be consulted.
CRC CARE Technical Report no. 38d 10
In its June 2016 statement, enHealth recommended drinking water guidelines of
0.5 g/L and 5 g/L for PFOS (+PFHxS) and PFOA respectively, based on 10% of the
EFSA (2008) tolerable daily intake allocated to drinking water.
Table 3 Summary of groundwater HSLs for PFOS and PFOA
Groundwater beneficial use PFOS (+PFHxS) PFOA
Drinking water 0.5 g/L* 5 g/L *
Primary contact recreation 5 g/L* 50 g/L *
Stock water Not derived Not derived
Irrigation/agriculture Not derived Not derived
Maintenance of ecosystems (marine)
Refer ESLs Refer ESLs
Aquaculture (fresh water) 21 ng/L (refer to section 2.3) 210 ng/L (refer to section 2.3) * Based on enHealth (2016) interim drinking water quality guideline
Table 4 Considerations in the application of groundwater HSLs for PFOS and PFOA
Groundwater beneficial use
Commentary and considerations
Drinking water Drinking water quality guidelines presented by enHealth (2016) apply to all sources of drinking water, including extracted groundwater.
Primary contact recreation
NHMRC 2008 specifies that it may be appropriate to apply a factor for 10 to drinking water standards to account for limited ingestion of recreational waters during swimming activities. Recreational water quality guideline presented by enHealth (2016) has adopted this approach.
Stock water for protection of animal products (milk, meat, eggs)
PFOS and PFOA can biomagnify in the food chain to varying extents. Limited data and information on this issue makes the derivation of a screening level that will avoid contamination of food products difficult. Drinking water HSLs do not apply (an important consideration is that water ingestion rates differ for animals).
Assessment on a site-specific basis may include direct sampling of PFOS and PFOA in animal products where animals have been exposed through drinking contaminated water.
Uptake of PFOS and PFOA by plants is possible, however this is highly variable and a screening level for irrigation and protection of agricultural products has not been derived. Drinking water HSLs do not apply.
Assessment required on a site-specific basis, and may include direct sampling of PFOS and PFOA in flora and biota.
Consumption of seafood
Assessment of groundwater impact on surface water bodies with regard to bioaccumulation and biomagnification in seafood should be undertaken on a site-specific basis.
If HSLs for surface water (human consumption of fish) are applied to groundwater, considerations may be made for issues such as complexities of groundwater-surface water interactions, benthic-biota bioaccumulation factors, the mass flux of the groundwater discharge to the surface water, and the flowthrough rate of surface water body. Where possible, direct sampling of PFOS and PFOA in fish can be considered.
Refer to section 2.3 for surface water and sediment HSLs.
CRC CARE Technical Report no. 38d 11
2.3 Water and sediment (human consumption of seafood) HSLs
HSLs have been derived for surface waters (fresh and marine waters) and sediment for
the protection of human consumption of seafood. The HSLs are summarised in table
5Table 5, and considerations for their application are provided in table 6.
Table 5 Summary of derived surface water and sediment HSLs for PFOS and PFOA
Media PFOS (+PFHxS) PFOA
MPCfish 270 g/kg 2,700 g/kg
HSLfresh water, fish consumption 21 ng/L 210 ng/L
HSLmarine water, fish consumption 616 ng/L 6,100 ng/L
HSLsediments 22 g/kg 220 g/kg
MPC maximum permissible concentration
Table 6 Considerations in application of surface water and sediment consumption of fish HSLs for
PFOS and PFOA
Nature of surface water body
HSLs for consumption of edible fish and crustaceans are only applicable to water bodies where fishing or harvesting of edible crustaceans occurs (associated habitats/niches of such species, including locations of their nurseries, may also be of interest in risk assessments). The HSLs do not typically apply to water bodies such as small drains, ponds and creeks where these activities do not occur, unless they are connected to other water bodies (in which instance the HSLs would apply in the receiving water).
HSLs for consumption of fish and crustaceans should not be applied directly to groundwater. The exception is where aquaculture is considered as a relevant beneficial use by the local jurisdiction.
The HSLs may be applied to the connected surface water body to reflect the exposure that will be relevant to the edible fish and crustaceans. The sediment HSLs are applied to the sediments where fish, crustaceans and benthic organisms of interest are in contact with the sediments. (Refer to part 3, section 3.4. regarding considerations for pore water)
Direct measurement applies to edible portions, typically muscle flesh although there exceptions such as roe and small fish such as sardines where the whole fish is eaten.
Groundwatersedimentsurface water interactions
If the fish are pelagic (living in the middle depths and surface water), then the concentration of the contaminant in the water body and food ingestion likely to be relevant, rather than the concentration in the sediment or at the point of discharge (see below regarding benthic-biota interactions). Estimates of the mass flux discharge to the receiving water that will occur may provide a useful indicator of the receiving water concentration.
Because of the potential for magnification along the food web, accumulation within organisms that are in contact with the sediments and are then consumed by fish may be of interest (note that PFOA biomagnification in marine food chains has not usually been found to be a significant issue). Where there is uncertainty as to the situation that applies, sampling and direct measurement of contamination in the fish or crustaceans of interest may provide a more direct measure of the situation. PFOS and PFOA concentrations measured in fish should be compared to the MPCfish values presented in table 5. Direct measurement applies to edible portions, typically muscle flesh although there exceptions such as roe and small fish such as sardines where the whole fish is eaten.
CRC CARE Technical Report no. 38d 12
2.3.1 Multiple pathway exposure and cumulative risk
Schedule B(4) of the NEPM (2013) specifies that when assessing the risk of combined
exposure, all relevant exposure routes must be included. This is important in the
context of PFAS investigations as exposure to PFAS contamination can occur through
soil, groundwater and the food chain, through more than one mechanism due to its
persistence, mobility and bioaccumulation properties.
In addition, the recent toxicological information suggests an additive effect between
PFAS and their derivatives, and therefore assessment should be made for cumulative
risks of the chemicals. A specific example of this is enHealths 2016 statement that the
EFSA (2008) tolerable daily intake for PFOS should apply to PFOS and PFHxS, and
the derived drinking water quality guideline should apply to the sum of PFOS and
The HSLs presented in preceding sections were derived independent of other
exposure routes. For example, the estimate of exposure occurring through soil
ingestion (direct contact with soil) does not consider whether there might also be
exposure through groundwater used for domestic (including potable) use or to water
HSLs for some exposures are calculated using a 100% relative source contribution. If
more than one of these sources is relevant, use of the screening values would
underestimate risks, and in this case, cumulative assessment of all relevant exposures
must be made. To evaluate the overall risk the cumulative fraction should be
calculated as follows:
That is, the PFAS concentration in soil, groundwater and surface water, is divided by
the relevant HSL for the relevant media and use. A fraction above 1 of any one of the
media indicates an exceedance of the HSL. The sum of these fractions is the
cumulative fraction and a result above 1 indicates an exceedance when all routes are
considered. This calculation can also help with the investigation and management of
risk as the pathways which pose the more significant risk can be identified.
CRC CARE Technical Report no. 38d 13
3. Ecological screening levels (ESLs)
The background information and derivation of ESLs is provided in part 3 of this
guidance document. This section provides a brief summary of the ESLs for terrestrial
and aquatic ecosystems, and considerations in the application of the ESLs. For a
discussion about the derivation and limitations of these screening levels, refer to part 3.
3.1 Freshwater ecosystem ESLs
Screening levels for PFOS and PFOA are currently being derived by the
Commonwealth Department of Agriculture and Water Resources for inclusion in the
revision of the ANZECC/ARMCANZ (2000) water quality guidelines. At the time of
preparation of this report, these guidelines were currently under review and were in
draft form. Table 7 shows the draft PFOS default guideline for each percent species
protection value. The 95% confidence limits were not provided in the draft documents.2
Table 7 Default guidelines for PFOS and PFOA
% Species protection PFOS g/L PFOA g/L
99 0.00023 19
95 0.13 220
90 2.0 632
80 31 1,824
3.2 Marine ecosystem ESLs
A summary of ESLs derived for PFOS and PFOA in marine environments is provided in
Table 8 Marine ESLs for fresh PFOS and PFOA
% Species protection PFOS g/L PFOA mg/L
99 0.29 3
95 7.8 8.5
90 32 14
80 130 22
3.3 Terrestrial ecosystem ESLs
The ESLs derived for protection of terrestrial ecosystems are summarised in table 9.
Table 9 ESLs values for fresh PFOS and PFOA in soils
Land use % Species protection
% Species protection
Commercial and industrial 65 60 60 48
Urban residential and public open space
85 32 80 17
National parks/areas with high ecological values
99 6.6 99 0.65
2 Perfluorooctanoic Acid (PFOA) Fresh. Default Guideline Values for Toxicants. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. November 2015. Final Draft Perfluorooctane Sulphonate (PFOS) Fresh. Default Guideline Values for Toxicants. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. August 2015. Final Draft
CRC CARE Technical Report no. 38d 14
3.4 Considerations in the application of ESLs
Aspects that should be considered in the application of ESLs are summarised in
Table 10 Considerations in the application of ESLs
Contaminant aging and soil properties
At present there is insufficient information to predict the influence of contaminant aging or soil properties on PFOS and PFOA bioavailability. The terrestrial ESLs assume 100% bioavailability, and are appropriate for non-aged PFOS and PFOA contamination. Studies suggest that the toxicity of PFOS and PFOA reduces with time (although there is insufficient information to quantify this), and a line of evidence approach could be adopted whereby consideration may be given to soil properties (e.g. TOC, pH, CEC, particle size, clay content, meso-pore fractions, organic carbon to total nitrogen ratio). Soil results are then compared with the ESLs following the NEPM ecological risk assessment procedure. This can be expected to provide a conservative assessment of the bioavailable fraction of PFOS and PFOA for use in an ecological risk assessment, and avoids the need to determine either an aging factor or a factor based on soil property effects.
Sample extraction methods for evaluating impact on terrestrial and aquatic organisms
The concentrations of PFOS and PFOA determined in sediment samples can vary depending on the type of desorbant used, with methanol extraction resulting in significantly higher concentrations than water extraction for PFOS, but similar concentrations for PFOA (Victor et al. 2015). It is possible that the use of a methanol desorbant may overestimate the amount of PFOS that is bioavailable to aquatic organisms. Similar considerations apply when determining the bioavailability of PFOS in soil.
Location and extent of potentially affected area
The ESLs apply to soil where the soil interacts with ecological systems, or may interact in the future. If soil is permanently contained under a structure or building, for example, the ESLs may have less relevance if the leaching potential is limited. Local regulators guidance on the application of the ESLs should be referred to.
Australian regulatory agencies generally require that, where groundwater discharges through a shoreline or bed of a river, that the benthic organisms at the point of discharge (prior to dilution in the bulk receiving water) be protected. Aquatic ecosystem protection is prescribed for groundwater dependent ecosystems (e.g. stygofauna) as a protected environmental value of groundwater.
Because of the potential for PFAS to bioaccumulate, concentrations within the sediments at the point of discharge may be elevated. When evaluating such areas, the environmental values of the receiving environment must be taken into consideration. The extent of shoreline or sediment that is potentially affected and its significance with respect to the whole of the water body and associated sediment may be considered. If the area of effect and contaminant loading are small and the environmental values are not affected to any significant degree, it may be appropriate to conclude that it is a low risk situation (this excludes the consideration of intentional release of pollutants which would be unacceptable and subject to jurisdictional legislation). However, such a conclusion would need to consider local regulatory requirements and it may be necessary to consult with the relevant agency or auditor in finalising a conclusion relating to such areas. For example, the ESLs do not consider other environmental values such as public amenity and cultural and spiritual values that may apply.
CRC CARE Technical Report no. 38d 15
PFOS is bioaccumulative, and the ESLs for protection of ecosystems take this into account as follows:
For aquatic ecosystems, in the case of moderately modified freshwater and marine ecosystems, the guideline for 99% protection of species for PFOS is recommended to be applied rather than the criterion for protection of 95% of species.
For terrestrial ecosystems, an increase of 5% species protection is added to the standard species protection levels for PFOS.
Given the variability of ecosystems, it may be appropriate conduct site-specific assessments using suitable data (see considerations for bioaccumulating chemicals in ANZECC/ARMCANZ (2000).
CRC CARE Technical Report no. 38d 16
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National Measurement Institute and CRC for Contamination Assessment and
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