Risk-based assessment, remediation and management of PFAS site contamination
crcCARE has published a practitioner guide for the assessment, remediation and management of site contamination for two per- and poly-fluoroalkyl substances (PFAS): perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA).
Governments published the PFAS National Environmental Management Plan (NEMP) in February 2018. The NEMP is a high-level document that covers a suite of PFAS issues and indicates the activities that need to be undertaken to manage those issues. The crcCARE practitioner guide focuses specifically on assessment and remediation of PFAS-contaminated sites, and covers both the ‘what’ and the ‘how’ of assessment and remediation. The guide incorporates:
- a risk-based approach to assessment, remediation and management
- screening values that are compatible with those in the NEMP
- practical advice for regulators and practitioners.
The guide, which is consistent with and complements the overarching NEMP, is expected to be very useful for remediation practitioners.
PFOS and PFOA
PFOS and PFOA belong to a large group of compounds called per- and poly-fluoroalkyl substances (PFAS). PFAS are highly persistent, bioaccumulative and potentially toxic to humans and the environment. These two chemicals have been used historically to improve the ability of firefighting foam to smother fire. In such ‘aqueous film-forming foams’, or AFFFs, these chemicals have been used on fires at many thousands of emergency and training sites worldwide over the past half-century. They are also widely used to treat fabrics and leather, and in paper products, non-stick cookware, food packing and insecticides.
There is evidence that PFOS and PFOA are potentially harmful to human and environmental health. Prominent news coverage has been given to PFOS and PFOA contamination in Williamtown, NSW, and Oakey, Queensland, as a result of historical firefighting training exercises (see the case study on CRC CARE’s work to clean up AFFFs, as well as information on matCARETM, a crcCARE-developed technology for remediating PFOS and PFOA).
In 2014, given a lack of well-established guidance on managing PFOS and PFOA, crcCARE enhanced its Project Advisory Group, comprising regulators, scientific experts and industry, to oversight the development of guidance for PFOS and PFOA. The ultimate aim was practical, user-friendly national guidance for regulators (environment protection authorities) and other parties involved in the management of PFOS and PFOA contamination.
crcCARE has subsequently published the Practitioner guide to risk-based assessment, remediation and management of PFAS site contamination, which aims to provide a consistent, risk-based approach to the assessment, management and remediation of PFAS contamination in Australia. It includes:
- human health screening levels (HSLs) and ecological screening levels (ESLs) for PFOS and PFOA contamination in soil, groundwater, surface water and sediment
- a framework and discussion regarding the application of these screening values
- a risk-based approach to the management and remediation of PFOS and PFOA contamination.
Complementing the practitioner guide and also available for download is crcCARE Technical Report 42: A human health review of PFOS and PFOA, which provides an overview of the international studies used in considering tolerable daily intake (TDI) values. It also recommends background intake levels for PFOS and PFOA in Australia, which may be useful when assessing multiple exposure pathways.
PFOS/PFOA proficiency testing study
The National Measurement Institute (NMI) of Australia has conducted two proficiency studies for PFOS and PFOA. crcCARE supported the 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:
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:
The data from both proficiency testing studies show variations in results for the same sample, therefore it is important to understand what is being reported. A further study is being planned by NMI in the near future.