Legacy and emerging per- and polyfluoroalkyl substances (PFASs) in Australian biosolids

Biosolids samples were collected from 19 Australian WWTPs during 2018 that cover a range of catchment types (urban, rural, industrial waste discharges) and treatment technologies. Samples were analysed for 44 PFAS using isotope dilution and alkaline extraction coupled with quantification with LC-MS/MS. The Sigma(44)PFAS mean concentration was 260 ng/g dry weight (dw) and ranged between 4.2 and 910 ng/g dw. The dominant compound class detected were the di-substituted phosphate esters (Sigma(3)PAPs mean 140 ng/g dw; range ND - 730 ng/g dw) which contributed 45% of the total mean Sigma(44)PFAS mass, followed by perfluoroalkyl carboxylic acids (Sigma 11PFCAs mean 39 ng/g dw; range 2.3-120 ng/g dw) contributing 17%, and the perfluoroalkyl sulfonates (Sigma 8PFSAs mean 28 ng/g dw; range 0.9-220 ng/g) which contributed 16%. Using the population data supplied by the participating WWTPs, the mean annual estimated biosolids-associated PFAS contribution is 6 mg per person per year and ranged between 0.6 mg and 15 mg. A similar population normalised concentration regardless of WWTP, region or capacity suggests that the domestic environment provides the baseline PFAS loading. Statistically significant higher Sigma(44)PFAS and PFOS concentrations were observed at urban locations. A weak correlation was observed between annual mass of PFAS associated with each individual WWTP and their percentage industrial waste contribution. This may be important for elevated PFAS concentrations observed in WWTPs with higher industrial waste inputs and requires further research. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Biosolids samples from 19 Australian WWTPs were analyzed for 44 PFAS, with di-substituted phosphate esters being the dominant compound class contributing 45% of total PFAS mass. Higher PFAS concentrations were observed in urban locations, and there was a weak correlation between PFAS mass and percentage industrial waste contribution in WWTPs.