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

New research has uncovered 'highly elevated' concentrations of PFAS chemicals in young sparrows residing in Melbourne's southwestern suburbs. The findings offer a stark warning about the persistent legacy of these 'forever chemicals' within urban ecosystems, particularly near sites with historical contamination.

Scientists from Macquarie University, in collaboration with the Environment Protection Authority (EPA), meticulously analysed blood samples collected from house sparrows across 16 locations previously identified as PFAS-contaminated. These sites included the former RAAF Williams-Laverton base at Williams Landing, the Altona Wastewater Treatment Plant, and a chemical plant and oil refinery, all situated in Altona.

Significant Contamination Near Former Defence Sites

The study, published in the journal Environmental Science and Technology, revealed that the average level of the PFAS chemical perfluorooctane sulfonate in these young sparrows was a staggering 10 times higher than that found in birds from an uncontaminated rural site in Norway. While the detected levels were not as extreme as some researchers had initially anticipated for known contamination zones, they were several times greater than those observed in sparrow populations elsewhere in Melbourne.

Lead author Dr. Max Gillings noted that the RAAF Williams-Laverton site recorded the highest levels of contamination. "We did find highly elevated levels of PFAS in the blood of those birds," Dr. Gillings stated. He explained that a portion of the former base has since undergone rehabilitation and redevelopment into the residential suburb of Williams Landing, with a significant amount of the team's sampling conducted within this suburb.

The sparrows exhibiting the highest PFAS concentrations were exclusively found within the RAAF Williams-Laverton base, a site historically used as a major air force firefighting training facility. Birds in this area primarily fed on insects within the restricted defence land. The study did not find strong evidence of widespread off-site contamination, indicating that the most severe impact remained localised to the source.

The Department of Defence has long acknowledged the PFAS issue at this site. Prior to the development of Williams Landing, extensive rehabilitation efforts were undertaken in contaminated areas designated for residential conversion. However, Dr. Gillings' data suggests that "if sparrows are feeding from areas on these bases – so, private military areas, essentially – that there still is legacy contamination in those areas."

The Department of Defence maintains a dedicated online resource detailing its management of PFAS at RAAF Williams-Laverton and its Point Cook base. Investigations by Defence have indicated that PFAS contamination had spread into the suburb of Williams Landing due to redevelopment activities, identifying the consumption of homegrown fruit and vegetables on former Defence land as a potential elevated risk. Despite this, a departmental spokesperson reassured residents, stating, "a Human Health Risk Assessment for RAAF Williams–Laverton found the PFAS exposure risk to human health is low." Further risk assessments and environmental studies are ongoing, with Defence prioritising community support through remediation programs.

Understanding 'Forever Chemicals' and Bioaccumulation

PFAS, an acronym for per- and polyfluoroalkyl substances, represents a vast family of over 14,000 synthetic chemicals. Historically, they have been widely incorporated into products ranging from firefighting foams and pesticides to building materials and electronics. These compounds are commonly referred to as 'forever chemicals' due to their remarkable resistance to environmental degradation, allowing them to persist in the environment for exceptionally long periods.

A critical characteristic of PFAS is their ability to accumulate within organisms and move up the food chain, a process known as bioaccumulation. Dr. Gillings' team observed that these chemicals were being transferred from mother birds to their eggs, and subsequently from contaminated insects consumed by newly fledged chicks during their early development.

"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 chosen for the study due to their confined home ranges, offering precise insights into localised contaminant levels. While recaptured birds showed declining PFAS levels as they matured, evidence suggested that early-life exposure could lead to physiological and genetic consequences, including higher rates of egg failure. The long-term implications for reproduction and development, however, remain a subject of ongoing investigation.

Wider Implications for Urban Wildlife and Public Health

The Environment Protection Authority (EPA) acknowledges the study as a significant contribution to understanding PFAS movement through urban land-based ecosystems. Deputy Chief Environmental Scientist Caroline Martino highlighted that the report would bolster the EPA's comprehension of PFAS and enhance 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," she remarked, noting the consistency with international wildlife studies.

These findings echo previous local research. Last year, a team led by Ellis Mackay from the University of Melbourne's veterinary school examined PFAS levels in possums across Melbourne. Their analysis of 46 deceased common brushtail and ringtail possums revealed PFAS in every liver sample, positioning Melbourne's possums among the most contaminated small terrestrial mammals ever tested globally.

Ms. Mackay expressed no surprise at the sparrow study's outcomes. "Unfortunately, no," she commented. "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 emphasised that urban wildlife serves as critical 'environmental sentinels,' providing early indicators of broader environmental health issues.

"Although PFAS contamination is now ubiquitous around the world, this research led by Dr. Gillings is quite concerning," Ms. Mackay added. "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." She underscored the urgent need to prioritise the identification and management of any ongoing PFAS sources.