Elevated per- and polyfluoroalkyl substances (PFASs) in tap water and serum in a community near an abandoned paper mill

• A community exposed to a paper mill PFAS mixture (PFOA+PFOS) in tap water. • Public water users exposed to elevated PFAS (1600 ng/L) compared to private wells • Private well users were exposed to PFAS <220 ng/L. • Serum samples were analyzed for 35 PFASs using LC-MS/MS. • Public water users had 15-fold higher serum PFOA compared to private well users. In 2018, elevated concentrations of per- and polyfluoroalkyl substances (PFASs) (1600 ng/L) were discovered in municipal wells, and the groundwater contamination was linked to an abandoned paper mill landfill in southwestern Michigan. From 2020-2021, we conducted a detailed exposure assessment in this community to provide insights about the mixture of PFASs from a paper mill source in drinking water and their persistence in human serum following long-term exposure. Water and serum were analyzed for >30 PFASs using LC-MS/MS. Approximately half of the study participants had private wells with lower PFAS concentrations (<220 ng/L) compared to municipal water (1600 ng/L), therefore, they were assigned as low (private well) and high (municipal well) exposure groups. The three predominant PFASs detected in the municipal well, perfluorooctanoic acid (PFOA) (670 ng/L), perfluorooctane sulfonic acid (PFOS) (740 ng/L), and perfluorohexane sulfonic acid (PFHxS) (19 ng/L), were also the most abundant in serum. Participants with high drinking water exposure had serum PFOA, PFOS and PFHxS concentrations that were 15-fold, 5-fold, and 2-fold higher, respectively, compared to those in the low group. For each additional year participants reported drinking the municipal water, we observed a 6%, 4%, and 5% increase in serum PFOA, PFOS and PFHxS, respectively. Overall, these results highlight the role of drinking water as a predominant source of PFAS exposure and the risk that abandoned landfills can pose to drinking water in nearby communities. This study also establishes a baseline for long-term toxicological impacts and evaluation of intervention effectiveness.