PFAS in Australian raptor species: terrestrial biomonitors of environmental contamination in changing ecosystems

Per- and polyfluoroalkyl substances (PFAS) pose a growing concern for wildlife health, yet their prevalence and ecological impacts in Australian fauna remains largely unknown. Here, we assess PFAS concentrations in five Australian raptor species (wedge-tailed eagles Aquila audax n = 28; white-bellied sea eagles Icthyophaga leucogaster n = 7; powerful owls Ninox strenua n = 2; brown falcons Falco berigora n = 4 and brown goshawks Tachyspiza fasciata n = 3) utilizing liver samples from existing museum and research collections, opportunistically collected from various locations around southeast Australia between 2015 and 2023. We report, to our knowledge, the first global analysis of Aquila sp. PFAS liver concentrations. Thirteen PFAS were detected in 40 of 44 individual birds, with ∑₁₃PFAS ranging from below detection to 115.1 ng/g wet weight (ww). PFOS was the most prevalent (88.6% of all samples) followed by PFTeDA, PFDA, PFDoA and PFHxS. Concentrations overlapped with relevant published ranges, indicating comparable bioaccumulation risks despite Australia's lower population density and limited industrial sources. A significant positive relationship was found between PFAS concentrations and estimated mass-specific basal metabolic rate (BMR), with brown goshawks and brown falcons showing the highest burdens. Land-use analysis revealed associations with natural environments, demonstrating that PFAS contamination may extend into ecosystems managed for biodiversity protection. These findings show that Australian raptors are exposed to both legacy and replacement PFAS, and that physiology, ecology and landscape modify contaminant patterns. Biomonitoring of PFAS in raptors reveals diffuse and persistent risks to ecosystems, even in conservation areas.