Per- and polyfluoroalkyl substances (PFAS) contamination in a microtidal urban estuary: Sources and sinks

This study evaluates PFAS contamination and determines the major drainage sources to a temperate microtidal estuary, the Swan Canning Estuary, in Perth Western Australia. We describe how variability in these sources influences PFAS concentrations within this urban estuary. Surface water samples were collected from 20 estuary sites and 32 catchment sites in June and December from 2016 to 2018. Modelled catchment discharge was used to estimate PFAS load over the study period. Three major catchment sources of elevated PFAS were identified with contamination likely resulting from historical AFFF use on a commercial airport and defence base. Estuary PFAS concentration and composition varied significantly with season and spatially with the two different estuary arms responding differently to winter and summer conditions. This study has found that the influence of multiple PFAS sources on an estuary depend on the historical usage timeframe, groundwater interactions and surface water discharge.

Automated summary

This study assesses PFAS contamination and identifies the major drainage sources to the Swan Canning Estuary in Perth Western Australia. The results show that PFAS concentration and composition in the estuary vary significantly with season and spatially. Historical AFFF use on a commercial airport and defence base is likely responsible for the elevated PFAS levels from three major catchment sources. It is also found that the influence of multiple PFAS sources on the estuary depends on various factors such as historical usage timeframe, groundwater interactions, and surface water discharge.