Unsaturated PFOS and Other PFASs in Human Serum and Drinking Water from an AFFF-Impacted Community

Understanding
how exposure to aqueous film-forming foam (AFFF)-impacted
drinking water translates to bioaccumulation of per- and polyfluoroalkyl
substances (PFASs) is essential to assess health risks. To investigate
spatial variability of PFAS exposure in communities near an AFFF source
zone, blood serum was collected in 2018 from 220 adult residents of
El Paso County (Colorado), as were raw water samples from several
wells. C6 and C8 perfluoroalkyl sulfonates (PFSAs) were predominant
in serum and water. PFASs were most elevated in the water district
nearest the source zone (median ∑PFSA of 618 ng/L in water
and 33 ng/mL in serum). A novel PFAS, unsaturated perfluorooctane
sulfonate, was detected in >80% of water and serum samples at low
concentrations (≤1.9 ng/mL in serum). Drinking water wells
nearest the source zone displayed increased prevalence of perfluoroalkyl
sulfonamide precursors not detected in serum. Serum-to-water ratios
were the greatest for long-chain PFASs and were elevated in the least
impacted water district. Additional serum samples collected from a
subset of study participants in June 2019 showed that PFAS concentrations
in serum declined after exposure ceased, although declines for perfluoropentane
sulfonate were minimal. Our findings demonstrate that AFFF-impacted
communities are exposed to complex, spatially variable mixtures of
PFASs.