Background release and potential point sources of per- and polyfluoroalkyl substances to municipal wastewater treatment plants across Australia

Wastewater treatment plants (WWTPs) are known to be significant sources of per-and polyfluoroalkyl substances (PFAS) to the environment. In this study, PFAS were measured in the influent of 76 municipal wastewater treatment plants (WWTPs) serving approximately 53% of the Australian population. Of fourteen target PFAS, twelve analytes including six C5-C10 perfluoroalkyl carboxylic acids (PFCAs), four C4-10 perfluoroalkyl sulfonic acids (PFSAs) and two fluorotelomer sulfonates (6:2 and 8:2 FTS) were detected. Of these, PFOS, PFHxS and PFHxA had the highest median concentrations. The per capita background release of Sigma(12) PFAS to WWTP influent in Australia was estimated to be 8.1-24 mu g/d/per person. The background release was supplemented by contributions from catchment specific point sources (i.e., industry, airports, military bases, and landfills), whereby the number of industrial sites positively correlated with the per capita mass load of Sigma(12) PFAS (r = 0.5-0.63, p < 0.01). The per capita mass loads were extrapolated to the entire Australian population, with estimates suggesting that approximately 1 kg/d of Sigma(12) PFAS reach WWTPs in Australia (300-400 kg annually), with more than half of the PFAS (similar to 59%) attributed to background release and the remaining (similar to 41%) to catchment specific point sources. These data provide insight into the release of major PFAS to wastewater at a national scale in Australia.

Automated summary

Wastewater treatment plants in Australia are significant sources of PFAS, as shown in this study which measured PFAS in the influent of 76 municipal WWTPs. The study found that PFOS, PFHxS, and PFHxA were the most common PFAS detected. The per capita background release of Sigma(12) PFAS in Australia was estimated to be 8.1-24 μg/d per person, with contributions from catchment specific point sources.