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The human impact of possibly carcinogenic chemicals in Australia’s water needs to be investigated with more government funding.
Per- and polyfluoroalkyl substances (PFAS) constitute a class of over 14 000 chemicals that have been used extensively in a range of consumer and industrial products since the 1950s, including in firefighting foam, given their exceptional interfacial properties and stability.
As such, PFAS contamination to the environment is through a wide range of activities, including firefighting activities, stormwater, landfills, wastewater treatment plants and land application of biosolids.
Over the last 25 years, an increasing body of research has raised concerns related to the human health and (eco) toxicological impacts of some PFAS. For example, the World Health Organization now lists two PFAS as carcinogens or possible carcinogens: perfluorooctanoic acid (PFOA) as a Group 1 carcinogen and perfluorooctanesulfonic acid (PFOS) as a Group 2B carcinogen.
International governmental agencies (eg, European Environment Agency and Agency for Toxic Substances and Disease Registry) articulate a wide range of negative health outcomes associated with PFAS.
PFAS are essentially detectable in all of the world’s population; however, concentrations of PFOS and PFOA are generally decreasing.
Of concern, however, is the incidence of PFAS in blood levels above health-based guidance values.
Studying the extent of PFAs in our water
Our study published earlier this year in Nature Geoscience investigated the global extent of PFAS in our surface and groundwaters.
To do this we developed an extensive global dataset from 273 international studies since 2004, which included data for over 12 000 surface water, and 33 900 groundwater samples. As PFAS are not naturally occurring, any PFAS found in the environment was introduced from a wide range of consumer and industrial products, including aqueous film-forming foams (ie, firefighting foam).
Our study found that while Australia has no PFAS manufacturing facilities, there are a number of highly contaminated PFAS sites from firefighting activities. We show that a significant proportion of sampled surface and groundwater throughout the world exceeds PFAS drinking water guidance values, with the extent of exceedance depending on the jurisdiction and PFAS source. Note this relates to PFAS in environmental water and not typically drinking water.
Our study could not adequately quantify the future PFAS environmental burden as not enough PFAS are typically quantified when sampled.
Currently only three PFAS are regulated in the Australian Drinking Water Guidelines (ie, PFOA, PFOS and perfluorohexanesulfonic acid (PFHxS)), with a fourth likely to be added (ie, perfluorobutane sulfonic acid (PFBS)).
As such, water utilities typically only measure these three or four PFAS in drinking water, when PFAS is quantified. Of note is that a wider range of PFAS (eg, 28 PFAS) are quantified at Department of Defence firefighting sites but these data are typically only available in locked PDF files, making independent analysis and interpretation difficult.
In Australia to date, PFAS has typically only been quantified in drinking water when there is a suspected PFAS source close to a drinking water source. However, results from our study, and Sydney Water’s recent discovery of PFAS in drinking water at the Cascade filtration plant in the Blue Mountains, suggest that PFAS is likely to be found in drinking water even when there is no suspected source.
Greater scope needed
Regulators worldwide have often proposed or regulated a much wider range of PFAS in drinking water than that of Australia. One of the most restrictive recommendations for drinking water is Health Canada’s, with the sum of all PFAS being less than 30 ng/L, whereas the European Union recommends the sum of all PFAS being less than 500 ng/L or the sum of 20 select PFAS being less than 100 ng/L.
The recent NHMRC review of PFAS drinking water guidance limited their scope to only five PFAS (PFOS, PFHxS, PFOA, PFBS and hexafluoropropylene oxide dimer acid (GenX)) from the outset of their review, recommending that four be subject to drinking water criteria.
The rationale for limiting the scope to five PFAS is following US EPA health advisories. Of note is that the US EPA also now includes perfluorononanoic acid (PFNA) in their drinking water guideline recommendations (ie, a total of six PFAS).
The NHMRC has proposed updating their drinking water guideline, suggesting an acceptable level of:
• 200 ng/L for PFOA
• 4 ng/L for PFOS
• 30 ng/L for PFHxS
• 1000 ng/L for PFBS.
A range of PFAS is also subject to the Stockholm Convention for the protection of human health and the environment from persistent organic pollutants (POPs) (ie, PFOS, PFHxS, PFOA and potentially all long chain perfluoroalkyl carboxylic acids).
The new NHMRC draft drinking water guidelines do not include or consider all PFAS on the Stockholm Convention list.
Given this, it is recommended that the NHMRC consider a much wider range of PFAS for drinking water guidelines, which would be consistent with the European Union and Health Canada. Ultimately, the NHMRC may determine there is inadequate information for drinking water guidelines, but at the very least additional PFAS should be considered.
More government funding should be made available to facilitate investigation of the human health and ecosystem impacts of PFAS in addition to better understanding the environmental fate of PFAS.
Additionally, it is recommended that a much wider range of PFAS are quantified in our source and drinking waters (ie, beyond the three or four typically quantified), especially given the limited additional cost associated with quantifying additional PFAS.
In summary, PFAS is pervasive in the environment with unknown human and ecosystem impacts. Although PFAS is the focus of significant recent attention, additional focus should also be on society’s use, fate and impacts of anthropogenic chemicals more generally.
Professor Denis O’Carroll is the Managing Director of the Water Research Laboratory, UNSW Sydney.
The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.
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