Relations between concentrations of perfluoroalkyl substances (PFAS) in drinking water and serum in adults living near PFAS hotspots

Abstract

BACKGROUND & AIM: Contaminated drinking water (DW) is a major source of exposure to per- and polyfluoroalkyl substances (PFAS) at locations around PFAS production facilities, airports and air force bases with extensive use of firefighting foam. We investigated quantitative relations between concentrations in DW and serum of nine perfluorinated alkyl acids (PFAAs), a very persistent PFAS subgroup, in Swedish adult populations living near PFAS hotspots. METHODS: We established a data set that consisted of paired concentration measurements in DW and serum from 261 subjects in four areas receiving PFAA-contaminated DW and from 137 subjects living in an area with non-contaminated DW. The relations between PFAAs in DW and serum were examined using linear regression analysis. The regression equations enabled us to derive (i) PFAA serum concentrations due to background exposure from sources other than the local DW (e.g. food, dust and textiles), (ii) population-mean PFAA serum-water ratios (SWR) and (iii) PFAA concentrations in DW causing serum PFAA concentrations significantly elevated above background (DWES). RESULTS: PFAA concentrations in DW varied widely (2.5-1790 ng/L for ƩPFAA). The estimated mean background serum concentrations ranged from below 0.1 ng/mL (PFPeA, PFHpA, PFBS) to 5.2 ng/mL (PFOS). The increases in serum PFAA with increasing concentration in DW were statistically significant for all PFAAs except PFPeA and PFDA. SWR estimates were <10 for short-chained PFAAs and >30 for long-chained PFAAs. Calculated DWES ranged between 18 ng/L (PFOA) and 178 ng/L (PFHxA). CONCLUSIONS: Health risks from PFAAs are related to the body burden, reflected by their concentration in serum. For population exposure assessment, it is easier and less expensive to measure PFAA concentrations in drinking water and the relationships derived herein should be helpful in the risk assessment and risk management of PFAA in drinking water. KEYWORDS: drinking water, perfluoroalkyl substances, human biomonitoring