The unexpected discovery of a soon-to-be banned “forever chemical” in firefighting foams previously used in Australia has prompted concerns the chemical may be significantly more widespread in the environment than once thought.
Researchers from UNSW Sydney were analysing aqueous firefighting foams to characterise different types of per- and polyfluoroalkyl substances, known as PFAS, when they made the discovery.
They found a form of perfluorooctanoic acid (PFOA) — known as “branched PFOA” — was more prevalent than expected, and when firefighting foam was released into the environment, its branched PFOA concentrations doubled over time.
PFOA is classified as a human carcinogen by the International Agency for Research on Cancer, and is one of more than 14,000 different types of PFAS.
The study, published in Water Research, revealed the presence of branched PFOA in the environment may be significantly underestimated, including in waterways.
UNSW researcher Dr Jun Sun, who is the lead author of the study, in the lab. (Photo: Song Thao Le)
Researchers used a lab technique that mimics what happens to PFAS chemicals naturally in the environment but at a much faster rate.
They discovered branched PFOA was produced during that process.
Study co-author Denis O’Carroll said the finding was significant because branched PFOA was “previously undetected” in firefighting foams widely used across Australia.
“When firefighting foam is dispersed into the environment, even more of the branched PFOA will evolve because of the environmental transformations of some of the [other] types of PFAS, ” Professor O’Carroll, director of the UNSW Water Research Laboratory, said.
Australia is set to ban the import, use and manufacture of PFOA, PFOS and PFHxS from July 2025.
Professor O’Carroll said branched PFOA was included in that ban.
“It should have been phased out in firefighting foam already, but it could be in other products.”
A ‘significant concern’
PFAS are often dubbed as “forever chemicals” due to their resistance to decay. They can take hundreds or even thousands of years to naturally break down.
As well as firefighting foams, they’re also used for industrial purposes, such as pesticides and electronics, and household and personal care products such as cookware and dental floss.
Not only are they environmentally toxic, the synthetic chemicals can also build up in organisms and across food chains. This is known as bioaccumulation.
Professor O’Carroll said it was a “significant concern” that low traces of PFAS were estimated to be present in the blood of more than 99 per cent people worldwide. They’ve also been detected at unsafe levels in surface and ground water across the world.
Last month, Australia’s National Health and Medical Research Council (NHMRC) released a draft update to its 2018 guidelines around safe levels of PFAS in drinking water.
Of the thousands of types of PFAS available, the draft guidelines only focus on four: PFOA, PFOS, PFHxS and PFBS.
According to the NHMRC, no guideline value has been proposed for branched PFOA or any other branched PFAS compound.
“NHMRC will consider additional PFAS if advised by the Water Quality Advisory Committee,” a spokesperson said.
“Additional PFAS may be added … in the future as part of the rolling revision of the Australian Drinking Water Guidelines.”
Professor O’Carroll said there were “definitely gaps” in what types of PFAS are tested for in Australia, and that branched PFOA and its PFAS precursors should be subject to drinking water guidance and regular monitoring.
“I would strongly advocate that we should be looking for the broad range of PFAS that are out there,” he said.
“If you go to a lab and say, I want to analyse three, or 17, or 23, or 40 [PFAS] — it’ll be the same cost. You might as well get more information.”
‘A ticking time bomb’
University of Adelaide molecular pharmacologist Ian Musgrave, who was not involved in the study, said the research had “important implications for ongoing monitoring and remediation” of PFAS contamination in our environment.
He was surprised by the high concentrations of branched PFOA found in the samples.
The problem with many of the branched PFAS compounds is “there’s not necessarily a good analytical process for them as they can be hard to detect”, he said.
Contaminated PFAS foam found in the Belubula River along Central West NSW farmland. (ABC Central West: Micaela Hambrett)
Dr Musgrave also agreed with Professor O’Carroll about the importance in identifying and monitoring as many different types of PFAS chemicals in the environment as possible.
“[The study] clearly shows that the breakdown [of PFAS chemicals] can go in many ways … you might have a ticking time bomb in terms of concentrations.
“You can’t put up a sign and walk away, because the amounts will change over time.”
Removing PFAS from our waters
Moving forward, Professor O’Carroll said Australia needed to take a “measured response” to identifying and monitoring PFAS chemicals in our environment.
“We need to do more investigation, and we need to be pragmatic. We also need to work to develop technologies.”
The UNSW researchers have also been developing new ways to break down PFAS chemicals using zinc and vitamin B12.
Dr Musgrave said it was surprising that vitamin B12, under certain conditions, appeared to effectively break down PFAS.
He noted, however, that the process led to “highly fluoridated end products” that still had some level of toxicity, which isn’t ideal.
“But, on the other hand … you could use this as an initial system for breaking down PFAS into compounds which can then be handled by another system.”
Dr Musgrave said it was an interesting and important step forward, which could lead to faster remediation of contaminated sites.
