Per- and poly-fluoroalkyl substances (PFAS) are a large group of man-made chemicals which do not occur naturally in the environment. Recently the media has highlighted the concerns of regulatory agencies and property owners surrounding PFAS contaminated sites in a number of states across Australia (including at Fiskville (Victoria), Oakey (Queensland) and Williamtown (New South Wales)). This highlights the need to understand and thoroughly assess the potential for PFAS contamination to have occurred.
PFAS compounds have been used since the 1950s as ingredients for a wide range of industrial and commercial applications including (but not limited to) fire-fighting foams (Class B – flammable liquid foams), non-stick cookware, garment and carpet surface protection treatments (e.g. water and stain proofing), and metal plating. The two most commonly used PFAS compounds are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS).
PFOS, PFOA and a number of other PFAS compounds have been identified as persistent in the environment (i.e. they do not break down in environmental media) and bioaccumulative in both animals and humans.
The main exposure to PFAS in humans is as a result of eating food and drinking water containing these substances.
To date the majority of toxicological research has focused on the two most commonly used PFAS (PFOS and PFOA). Although research indicates the potential for toxic effects as a result of exposure in test animals, no causal link has been identified to date between exposure and toxic effects in humans.
In April 2016, a national workshop was convened to review international PFAS standards and draft Australian human health toxicity reference values for PFOS and PFOA. PFOS and PFOA were the focus of this review as these compounds have been most extensively studied by the scientific community. However more recently, studies into perfluorohexane sulfonate (PFHxS) have indicated that this compound can cause similar, but less potent, effects in laboratory test animals as PFOS. As such the enHealth workshop considered that, based on the available information for PFHxS, the PFOS interim values should also apply to PFHxS.
As a result of the national workshop, enHealth recommend the following interim values for use in assessing site contamination in Australia:
The sites where PFAS contamination is most likely to be found include those where Class B fire-fighting foams have been used, stored and released, and where PFAS has been used or disposed of including (but not limited to):
Former firefighting training facilities;
Petroleum refining and storage facilities;
Textile/carpet manufacturing facilities;
Land treated with biosolids from waste water treatment facilities; and
Consideration of the potential for PFAS contamination at sites where land uses as outlined above have been undertaken, and in the neighbouring areas where groundwater or waste water discharges may be occurring should be included as part of site contamination assessments.