Alarming PFAS Levels Detected in Melbourne's Urban Birdlife, Study Reveals

A team of researchers from Macquarie University and the Environment Protection Authority has discovered highly elevated levels of toxic PFAS chemicals in young sparrows in Melbourne's south-west.

The study, published in the journal Environmental Science and Technology, analyzed blood samples from house sparrows across 16 previously contaminated locations. These sites included the RAAF Williams-Laverton base at Williams Landing, the Altona Wastewater Treatment Plant, and a chemical plant and oil refinery in Altona.

Researchers revealed that the average level of the PFAS chemical perfluorooctane sulfonate in the young sparrows was ten times higher than that of birds in an uncontaminated rural site in Norway. While lead author Max Gillings noted the levels were lower than originally anticipated for known contamination sites, they remained significantly higher than sparrow populations in other areas of Melbourne.

Contamination Source at RAAF Williams-Laverton

According to the study, the worst-affected location was the RAAF Williams-Laverton base. We did find highly elevated levels of PFAS in the blood of those birds, Dr Gillings said. Part of it has now been rehabilitated and redeveloped into the suburb of Williams Landing, so a lot of our sampling was actually in that suburb.

Dr Gillings explained that firefighting foam previously used at the base was the likely source, with local birds mostly feeding on insects within the restricted military land. However, the study found no strong evidence of significant off-site contamination.

The Department of Defence has been aware of the PFAS issue at this site for quite a long time, Dr Gillings said. Prior to actually developing Williams Landing, they did conduct quite an extensive rehabilitation of the contaminated areas that they were converting into these residential environments.

He added: What our data does tell us is, certainly is that if sparrows are feeding from areas on these bases — so, private military areas, essentially — that there still is legacy contamination in those areas.

Defence Department Responds to Risks

The Department of Defence, which hosts a dedicated web page on PFAS management at RAAF Williams-Laverton and its Point Cook base, acknowledged that redevelopment activities had spread the contamination through Williams Landing. Eating homegrown fruit and vegetables on the former Defence land has been identified as a potential elevated risk.

However, a department spokesperson stated that the threat to residents is minimal. As part of the investigations, Defence conducted a Human Health Risk Assessment for RAAF Williams–Laverton which found the PFAS exposure risk to human health is low, the spokesperson said. Further risk assessments and environmental studies are underway.

The spokesperson added that Defence's priority remains to support communities impacted by PFAS contamination on and around Defence sites, by reducing their exposure to PFAS through Defence's remediation program.

Transmission of 'Forever Chemicals'

PFAS (per- and polyfluoroalkyl substances) are a group of over 14,000 synthetic chemicals. Because they are highly resistant to decay, they are commonly referred to as "forever chemicals" and tend to build up in food chains through bioaccumulation.

The study found that these chemicals are passed down from mother sparrows to their eggs, and also transmitted via the insects fed to young fledglings. Birds are in contact with the sources in the environment where PFAS tends to accumulate, so that's things like soil and dust but also through the ingestion of insects and water as well, Dr Gillings explained.

House sparrows were selected for the study due to their limited geographic movement. The reason we focused on house sparrows is that they have quite a confined home range, so they don't move very far from their nesting site … so it gives us a really good indication of kind of localised levels of that contaminant, Dr Gillings said.

While tests showed that PFAS levels in the birds generally fell as they aged, early exposure appears to cause genetic and physiological issues. Egg failure rates are associated with high levels of PFAS, so you'll have more eggs failing during the breeding season. However, Dr Gillings added, In terms of the long-term effects, though, we're not actually sure what the overall implications are for things like reproduction and development.

Impacts on Local Ecosystems

The Environment Protection Authority (EPA) welcomed the findings, stating that the research offers valuable insights into how PFAS moves through urban land-based ecosystems. Caroline Martino, the EPA's deputy chief environmental scientist, said the study strengthens their ecological risk assessments.

It is one of the first Australian studies to clearly demonstrate PFAS movement through a terrestrial food web in an urban environment, including transfer from adult birds to their offspring and through diet, Dr Martino said. The findings are consistent with our existing understanding that PFAS can persist and accumulate near known source areas, and the patterns reported in young sparrows align with findings from international wildlife studies.

This study follows research conducted last year by Ellis Mackay and a team from the University of Melbourne's veterinary school, which analyzed PFAS levels in local possums. They detected the chemical in the liver samples of all 46 common brushtail and ringtail possums tested, concluding they were among the most contaminated small land mammals tested globally.

Ms Mackay said she was not surprised by the new findings. Unfortunately, no, she said. Elevated PFAS levels have been documented in a range of wildlife species across the Melbourne region, including black swans at Albert Park Lake, dolphins in Port Phillip Bay, and ringtail and brushtail possums from across the city.

She warned that urban wildlife serves as an environmental warning system. Although PFAS contamination is now ubiquitous around the world, this research led by Dr Gillings is quite concerning. She added that The overall PFAS levels observed are quite high, especially from the Williams–Laverton air force base site, and the finding of elevated PFAS in fledgling birds is a particular worry as it could potentially have a range of impacts during a vulnerable stage of development.

Ms Mackay emphasized that locating and managing existing PFAS sources must be made a priority.