Tejal Somvanshi
Scientists at the University of New South Wales have discovered 31 types of PFAS chemicals in Sydney’s tap water, with 21 of these never before detected in Australian drinking water. The findings, published in the journal Chemosphere, reveal a wider presence of these persistent substances than previously known.
PFAS, or per- and polyfluoroalkyl substances, are synthetic chemicals used in everyday products like non-stick cookware, water-resistant fabrics, and firefighting foams. They’re called “forever chemicals” because they don’t break down naturally and can remain in the environment and human bodies for decades.
Among the newly identified substances was 6:2 diPAP, detected in tap water globally for the first time. Previously, this chemical had only been found in bottled water and consumer products. Another compound, 3:3 FTCA, a breakdown product from firefighting foams, was detected for the first time in Australian drinking water.
“Sydney’s water meets current Australian standards, but when considering health benchmarks used in other countries, some samples were near or above safety limits,” said lead researcher Professor William Alexander Donald from UNSW’s School of Chemistry.
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The researchers tested 32 tap water samples from four catchment areas across Sydney – Ryde, Potts Hill, Prospect, and North Richmond. The highest concentrations were found in North Richmond, where PFOS, a known carcinogen previously used in firefighting foam, measured 6 parts per trillion (ppt).
This level falls below Australia’s guideline of 8 ppt but exceeds the U.S. Environmental Protection Agency’s advisory limit of 4 ppt. To understand how small these measurements are, one part per trillion is equivalent to a single drop of water in 20 Olympic-sized swimming pools.
The most abundant chemical found was PFBA, a short-chain PFAS present in every tap water sample tested. PFBA is increasingly used as a replacement for regulated long-chain PFAS but remains highly mobile in water and environmentally persistent.
“It shows this idea that you can make tweaks to these chemicals to get around using the banned substances, but then it ends up in our tap water,” Professor Donald explained.
The researchers used highly sensitive testing methods to detect these chemicals at extremely low levels. Dr. Lisa Hua, who led the laboratory analysis, employed mass spectrometry to identify chemicals by measuring the weight of their molecules.
“It should be reassuring that these PFAS concentrations are low,” Dr. Hua said. “However, we should explore new technologies that remove PFAS before their release into our ecosystems and drinking water supply.”
Professor Donald highlighted the regulatory challenges these findings present. “We are stuck in a whack-a-mole situation with PFAS,” he said. “Tiny tweaks to the chemical structure create a ‘new’ compound, but the toxicology research and regulatory work has to start all over again every time a PFAS is tweaked.”
This fragmented approach to regulation is why Europe has moved toward regulating PFAS as a class rather than individually. Meanwhile, Australia reduced its PFOS guideline to 8 ppt in 2025, down from 70 ppt previously.
The findings come as NSW Health recently released results from an expert advisory panel on PFAS, which concluded that “the health effects of PFAS appear to be small” and found “no clinical benefit for an individual to have a blood test for PFAS.”
Sydney Water maintains that drinking water from all nine of its water filtration plants is safe to drink and meets the Australian Drinking Water Guidelines.
The researchers recommend expanding PFAS monitoring across Australia to better understand seasonal variations and establish a more complete baseline of these chemicals in drinking water supplies.
