Predictors of Serum Per- and Polyfluoroalkyl Substances (PFAS) Concentrations in a Rural Agricultural Community...

Human exposure pathways to PFAS from contaminated biosolids applied as fertilizers are not well understood. In the Maine Biosolids Study, we examined predictors of serum PFAS concentrations in adults (N = 144) living near sites of historical agricultural biosolids application. All participants had PFAS concentrations measured in their private drinking well water by the Maine Department of Environmental Protection from 2020 to 2023. In late 2023, we measured serum PFAS concentrations and administered a survey on water-related, occupational/recreational, residential, local food intake, and sociodemographic/health characteristics. We used multivariable linear mixed-effects models to examine associations of each predictor with serum concentrations of perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid, perfluorooctanoic acid (PFOA), perfluorononanoic acid, and perfluorodecanoic acid. Daily PFAS water intake was the strongest predictor of each serum PFAS, explaining between 22% (PFHxS) and 40% (PFOA) of the variance. Males, postmenopausal females, frequent consumers of local eggs, and those who worked with biosolids on a farm or in another capacity also had higher concentrations of select PFAS than other participants. Together, the predictors studied explained 38-52% of the total variance in serum concentration of each PFAS. Future studies will help further investigate local egg consumption and working with biosolids to inform mitigation strategies in biosolid-impacted communities.