Ellen Phiddian
Cosmos science journalist
Australians are set to have stricter guidelines on PFAS “forever chemicals” in their water, after a review by the National Health and Medical Research Council (NHMRC).
The council has published new draft recommendations for the concentrations of PFAS in drinking water.
The new thresholds are significantly lower than those set in 2018, during the last review, and they include new limits on certain PFAS.
“Since that time, there’s been quite a lot of work done in the area,” says NHMRC CEO Professor Steve Wesselingh, adding that other jurisdictions like the USA’s Environment Protection Agency have recently updated their guidelines.
Few Australian water supplies exceed the new limits.
PFAS, or per- and polyfluorinated alkyl substances, are synthetic materials made of long, carbon-based polymer molecules containing a lot of fluorine.
Also called “forever chemicals”, these materials are highly inert – making them useful for both heat resistant and non-stick materials, such as pan coatings and firefighting foam.
More than 10,000 PFAS compounds have been designed and used in a wide range of anthropogenic products. (For more on PFAS, read our explainer.)
Because they’re so inert, PFAS break down very slowly in the environment and in human bodies, meaning they can cause health problems. Some PFAS have been shown to be carcinogenic.
“PFAS began to be phased out in Australia in the 2000s and the levels of PFAS detected in the Australian population has steadily dropped since then,” says Dr Ian Musgrave, a toxicologist at the University of Adelaide, who wasn’t involved in the review.
“Now that industrial use has been phased out, the main way we are exposed to PFAS is through things like persistent environmental contamination including drinking water from contaminated environmental sources.”
Researchers have estimated that about 2-3% of PFAS exposure comes from drinking water in Australia, rising to 22-24% when there are contaminated supplies.
Previously, the NHMRC had thresholds for 3 common PFAS: perfluorooctanic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS) – at 560 nanograms per litre, 70ng/L, and 70ng/L respectively.
The new guidelines update the restriction on PFOA to 200ng/L, PFOS to 4ng/L, and PFHxS to 30ng/L.
It also adds in a restriction on another compound – perfluorobutane sulfonic acid (PFBS) – setting the limit at 1000ng/L.
The team also reviewed the “GenX chemicals” – hexafluoropropylene oxide dimer acid ammonium salt plus hexafluoropropylene oxide dimer acid – but couldn’t find sufficient evidence to set a limit. GenX chemicals have never been detected in Australian drinking water, while the other 4 compounds have.
These updated guidelines are based on animal studies, extrapolated to the levels that would be expected to have an impact on human health.
“Importantly, this is based on an individual drinking water on a daily basis for their entire life,” says Wesselingh.
“So it’s not about the concentration that is toxic right now, but you need to be drinking above these levels for your entire life to have what we regard at the moment as toxic effects.”
The guidelines are open for public consultation until 22 November, with final guidelines expected in April next year.
Wesselingh says it’s “difficult to predict” if the final guidelines will change after the consultation.
“We are absolutely open to any additional evidence, ideas and thoughts from the public and from other agencies,” he says.
The concentrations outlined in the guidelines are rare in Australian drinking water. The NHMRC recommends a preventative approach to PFAS in water, with suppliers choosing high quality sources and monitoring those sources carefully.
Standard water treatment methods don’t filter out PFAS, but there are filters that have better success. Some are available as commercial home water filters, but they can carry other risks.
For instance, reverse osmosis filters yield extremely pure water, and have some success at removing PFAS. But purifying water to this extent removes chlorine, which prevents bacterial growth, and fluoride, which improves oral health.
Desalination plants, which typically use reverse osmosis, need to run the purified water through a “promineralisation” process where they add small amounts of other chemicals to make it drinkable.
The NHMRC doesn’t provide any advice on home water filters.
“We don’t generally rely on households producing their own treatment. We rely on providing safe drinking water to households,” says Dr David Cunliffe, a member of the NHMRC’s water quality advisory committee and principal water quality advisor at the South Australian Department of Health and Wellbeing.
“In a nutshell, my advice is: we are fortunate in Australia in that we have hardly any water that is affected by PFAS, and you should only be concerned if directly advised by the authorities,” says Dr Daniel Deere, a water and health consultant at consultancy Water Futures, who is currently consulting on PFAS for the World Health Organization.
“Remember that water utility staff and their regulators, and their friends and family, drink the same water that you do. They have no incentive or reason to provide unsafe water, or to hide information from the public,” says Deere.
“If levels of PFAS present a risk to your health in your water supply, 2 things will happen. Firstly, you will be notified within at most a few days of the problem being confirmed, as required under their regulations. Secondly, and as soon as reasonably practicable and affordable, the problem will be resolved through things like changing water sources or introducing PFAS removal treatment.”
