Urban possums as sentinels for environmental contamination: First evidence of PFAS in Australian marsupials

Per- and polyfluoroalkyl substances (PFAS) have been widely studied in aquatic animals, particularly in the Arctic, but relatively little is known about the state of contamination in terrestrial mammals, especially synurbic and urban dwelling species. This study is the first to show that Australian native marsupials are contaminated with PFAS. Liquid chromatography and tandem mass spectrometry analysis determined the levels of 75 PFAS in common brushtail possums (Trichosurus vulpecula) and common ringtail possums (Pseudocheirus peregrinus) from the Melbourne region (Victoria, Australia). The possums in this study were contaminated with at least 45 different PFAS. The concentration of perfluorooctanesulfonate (PFOS) in both species was most prominent, with a median ΣPFOS (linear and branched isomers) concentration of 74 ng/g (wet weight) in brushtail possum livers and 16 ng/g in ringtail possum livers. Two brushtail possum samples had ΣPFOS concentrations ≥200 ng/g. These PFOS concentrations are among the highest levels reported in small terrestrial mammal species globally. The possums in this study are sentinels for a broader problem of PFAS contamination in Melbourne that could be impacting Australian ecosystems and other native species. Further research is required to investigate the extent and severity of PFAS contamination in Australian fauna. This is crucial for native species found in urban environments that may be at a greater risk of exposure to PFAS and other persistent organic pollutants.