Screening of PFASs in groundwater and surface water

Per- and polyfluoroalkyl substances (PFASs) are emerging organic pollutants characterized by their persistency, and bioaccumulation and toxicity potential. In this study, 26 PFASs were screened in 502 water samples originating from Swedish groundwater, surface water, sewage treatment plant (STP) effluents and landfill leachates. The objectives were to establish baseline concentrations of PFASs in the aquatic environment, to screen for potential sources, and to compare PFAS concentrations with guideline values for estimation of potential effects on the ecosystem and human health. In drinking water source areas, the average ∑26PFAS concentration was 8.4 ng L-1 with a median value of 0.6 ng L-1 (n = 172). The drinking water guideline value of 90 ng L-1 for ∑7PFASs (PFPeA, PFHxA, PFHpA, PFOA, PFBS, PFHxS, PFOS) established by the Swedish National Food Agency was exceeded in 4 samples (2% of the total number of samples in this category). In water not used for drinking water, ∑26PFASs concentrations were on average 142 ng L-1 (median 5.4 ng L-1). The high average PFAS concentrations can be explained by the fact that some samples showed extremely high PFAS concentrations with a maximum ∑26PFASs value of 12 900 ng L-1. In surface water, PFOS concentrations exceeded the annual average Environmental Quality Standard (AA-EQS) of the EU Water Framework Directive (WFD) in 42% of the samples. Among the different water categories, the landfill leachates had the highest average concentration of ∑26PFAS with 487 ng L-1 (median 435 ng L-1, n = 10), followed by surface water (average 112 ng L-1, median 4.1 ng L-1, n = 285), groundwater (average 49 ng L-1, median 0.4 ng L-1, n = 164), STP effluents (average 35 ng L-1, median 26 ng L-1; n = 13) and background screening lakes (remote lakes; average 3.4 ng L-1, median 1.4 ng L-1, n = 10). The composition profile of the PFASs differed between the types of waters showing an even distribution of ∑PFCAs, ∑PFSAs and ∑PFAS precursors in groundwater, whereas in all other water categories (surface water, background lakes, STP effluents and landfill leachates), ∑PFCAs were dominant. As FOSA, PFNA, PFDA, and 6:2 FTSA were frequently detected in drinking water source areas (constituted 20%, 7.3%, 5.9%, and 4.4% of the ∑26PFASs, respectively), it is reasonable to consider the inclusion of these in the Swedish drinking water guideline.