MELBOURNE, Sept. 10 (Xinhua) -- An Australian study has found low levels of PFAS, or "forever chemicals," in rainwater collected in Melbourne, with concentrations of two well-known compounds below current drinking water guideline values.
Researchers from Australia's RMIT University and the Environment Protection Authority Victoria detected eight of 30 PFAS compounds tested in rainwater samples collected on three occasions between 2024 and 2025, according to a statement released by RMIT on Thursday.
"In our samples, concentrations of the two most well-known PFAS -- PFOS and PFOA -- were below current Australian drinking water guideline values, which should provide some reassurance for people who use rainwater as a source of drinking water," said lead researcher Professor Oliver Jones from RMIT's School of Science.
Based on the concentrations measured, researchers estimated rainfall could deliver about 10.6 kg of PFAS to Port Phillip Bay in the state of Victoria each year, equivalent to about 5.5 grams per square kilometer.
PFAS, or per- and polyfluoroalkyl substances, are a large family of human-made chemicals used in products including firefighting foams, food packaging, textiles, cosmetics and non-stick cookware. PFAS can travel long distances in the atmosphere on dust particles or tiny water droplets before returning to the environment through rain, the researchers said.
The estimate suggests rainfall could be an important pathway for PFAS entering waterways, alongside wastewater, urban runoff and landfill. The researchers hope the findings will support broader monitoring of PFAS in Australian rainfall and improve understanding of how these chemicals move through the environment.
The findings, published in Environmental Chemistry and Toxicology, also found that rain linked to air traveling over land had higher PFAS concentrations than rain linked to air traveling over the ocean, suggesting urban and industrial areas may be important sources of airborne PFAS deposited elsewhere through rainfall. ■
