A new study has revealed there may be a significant underestimation of a specific type of PFAS ‘forever chemical’ in firefighting foam.
The chemical, perfluorooctanoic acid (PFOA) which is used in firefighting foam, is classified as a human carcinogen by the International Agency for Research on Cancer.
Firefighting foams have historically been composed of Per- and poly-fluoroalkyl substances, known collectively as PFAS, and they can take hundreds or even thousands of years to naturally break down.
Low traces of PFAS are believed to now be present in more than 99 per cent of the global population and there are growing concerns about the level of contamination in water supplies, including drinking water.
The UNSW research showed that concentrations of branched PFOA in firefighting foam would double after time in the environment.
The researchers conducted what is known as a TOPA – a total oxidisable precursor assay – which simulates the oxidation process that helps create regulated PFAS naturally in the environment, but at a much faster speed.
UNSW Professor Denis O’Carroll said the firefighting foam was put through a test to mimic what would happen to those chemical compounds in the environment.
He said PFOA also exists in a linear form, but people have not really been looking or analysing the amount of branched PFOA.
“But in our samples we found that about 50 per cent was linear and 50 per cent was branched after TOPA,” he said.
CCN asked if there are plans to complete an analysis of PFAS in refrigerants and O’Carroll said refrigerants are likely to be similar in nature to firefighting foams.
He said researchers are concentrating on ways to degrade PFAS whatever the source.
"We actively work to degrade a range of PFAS. PFOA, and branched PFOA, which are found in a range of products,” he said.
"The water treatment technologies that we are developing would be able to degrade a range of these PFAS but not all PFAS of concern."
The Australian government recently proposed updating its drinking water guidelines suggesting an acceptable level of 200 nanograms per litre for PFOA. However, in April 2024 the US Environmental Protection Agency set its drinking water concentration limits for PFOA at just 4 nanograms per litre.
O’Carroll said more studies need to be done to properly identify the levels of as many potentially dangerous chemicals as possible.
“PFAS is actually a group of nearly 14,000 synthetic chemicals, but in Australia the authorities measure, monitor and advise on just three of them,” he said.
“We can identify in this paper that branched PFOA is likely to be more pervasive in the environment than currently anticipated. But then there are 14,000 other ones we could also be measuring.
“What I think this research shows, more broadly, is that we should be analysing for more than just a few of these PFAS that are out there and compiling a more holistic picture to help address these problems.”
The researchers have simultaneously been working on developing new catalysts that are able to break down PFAS chemicals.
This novel process is a form of reductive defluorination using a type of eco-friendly chemical reducing agent called zero-valent metals (ZVMs) in conjunction with vitamin B12 and its analogues.
Promisingly, a number of the various branched PFOA chemicals identified in the analysis of the firefighting foam degraded within 10 days when treated with zero-valent zinc and vitamin B12.