Researchers say a particular kind of PFOA may be more prevalent in the environment than predicted.

Experts from UNSW Sydney have identified previously underestimated levels of branched PFOA - a specific type of “forever chemical” in firefighting foam - potentially signalling broader environmental contamination. 

The study, published in Water Research, focused on branched perfluorooctanoic acid (PFOA), a type of per- and polyfluoroalkyl substance (PFAS) linked to environmental persistence and health risks.  

The study revealed that concentrations of branched PFOA in firefighting foam could double over time when exposed to environmental conditions. 

Using a technique known as Total Oxidisable Precursor Assay (TOPA), the researchers simulated the oxidative processes occurring naturally in the environment, uncovering unexpected chemical transformations.  

“This branched PFOA was actually an important product of that process. About 50 per cent of PFOA in the samples was found to be in the branched form after testing,” said Professor Denis O’Carroll, a co-author from UNSW’s School of Civil and Environmental Engineering.

These findings are significant as PFOA, a known human carcinogen, is part of the Stockholm Convention on Persistent Organic Pollutants. 

The revelation raises concerns about the broader prevalence of branched PFOA and similar chemicals in various environmental and consumer contexts.  

The detection of branched PFOA reveals gaps in monitoring standards. 

Currently, Australian guidelines for drinking water propose an acceptable level of 200 nanograms per litre for PFOA, a stark contrast to the United States Environmental Protection Agency’s stricter limit of 4 nanograms per litre set earlier this year.  

Studies have linked PFAS exposure to adverse health effects, including cancers and reduced immune responses. However, evidence of causation remains limited.  

Professor O’Carroll emphasised the need for comprehensive monitoring. 

“In Australia, authorities measure and monitor only three PFAS out of nearly 14,000 synthetic chemicals. We need a broader approach to identify the extent of environmental contamination,” he said. 

To address the persistence of PFAS, the UNSW team has developed a novel method using zero-valent zinc (ZVZ) combined with vitamin B12 to degrade PFAS. 

The process showed promising results, with branched PFOA breaking down within ten days under controlled conditions.  

“This method demonstrates a potentially faster degradation rate for branched PFOA compared to its linear counterpart, providing hope for remediation strategies,” said Professor Naresh Kumar from UNSW’s School of Chemistry.

However, challenges remain as the degradation products, while less fluorinated, retain some toxicity. 

Researchers suggest combining multiple treatment technologies for effective long-term remediation.  

Australia's National Health and Medical Research Council (NHMRC) recently released a draft update to its 2018 guidelines on safe levels of PFAS in drinking water.
The draft guidelines only focus on just four of the thousands of types of PFAS: PFOA, PFOS, PFHxS and PFBS.

The NHMRC says no guideline value has been proposed for branched PFOA or any other branched PFAS compound.

This email address is being protected from spambots. You need JavaScript enabled to view it. CareerSpot News