Per- and Poly-FluoroAlkyl Substances (PFAS) are a family of synthetic chemicals characterised by highly stable carbon-fluorine bonds. PFAS have found applications in various products, including non-stick cookware, fabric protectants, waterproof clothing, cosmetics, food packaging, and firefighting foams. This widespread use has resulted in significant environmental contamination and considerable public concern due to their reported associations with various health issues, such as immune system suppression, metabolic disorders, and cancer. However, comparatively little research has focused on how PFAS concentrations fluctuate over time and space across both short (24 hours) and long (2-3 years) timeframes. Furthermore, data on the effects of PFAS at environmentally relevant concentrations are notably lacking.
We first measured the concentrations of 44 PFAS hourly over a 24-hour period in three estuaries in Victoria. ΣPFAS exhibited 4-7-fold differences throughout the sampling period. Environmental measurements indicated that this variability was likely due to seawater diluting the PFAS concentration in the estuary during tidal influxes. As a result, randomly timed grab samples carry a significant risk of mischaracterising the true range of PFAS concentrations in estuarine systems.
We also evaluated PFAS concentrations in the major rivers flowing into Port Phillip Bay and in sediments. The results revealed substantial variations in the amounts and types of PFAS between summer and winter and across different years in the rivers, as well as a distinct depth profile in the sediments.
We then exposed freshwater amphipods to water from an urban wetland with known PFAS concentrations for 14 days and analysed their metabolite profiles. Mannose, Myo-inositol, and Isopropyl propionate were found to change in PFAS-exposed amphipods. Effects on the growth and reproduction of the exposed amphipods were also observed.
These findings contribute to our understanding of the temporal dynamics of PFAS in Port Phillip and their toxicity at environmentally relevant concentrations.