Sociodemographic Determinants of PFAS Contamination in United States Community Water Supplies: An Analysis of Sampling Data from 11 States

Abstract

Background and Aim Many studies show marginalized communities are disproportionately exposed to air pollution. However, relatively few studies have considered water quality disparities, including exposures to per- and polyfluoroalkyl substances (PFAS). We evaluated whether Community Water Systems (CWS) serving greater proportions of minority and low-income individuals had higher likelihoods of detecting PFAS and exceeding Maximum Contaminant Levels (MCL) using recent statewide drinking water monitoring data. Methods We compiled drinking water PFAS concentration data from 11 states with statewide monitoring data and ancillary data on sociodemographics, CWS characteristics, active PFAS treatment, and PFAS sources. We examined associations between PFAS concentrations in drinking water and sociodemographics at various spatial units for 4,698 CWS (serving 62.2 million people) using multivariate logistic regressions. Results CWS serving 20.8 million people (33%) had detectable concentrations (>5 ng/L) of at least one of five PFAS and those serving 16 million people (26%) exceeded the lowest state-level MCL for several PFAS. CWS with detectable PFAS levels and MCL exceedances served greater proportions of Hispanic and Black residents than those with PFAS levels below detection and without exceedances. At the county-level, a percentage point increase in the proportion of Hispanic residents served by a CWS was associated with a 4-6% increase in the odds of detecting PFAS. Results for state-level relationships were more mixed, although CWS in five of the 11 states had increased odds of detecting several PFAS for CWS serving counties with greater proportions of Hispanic residents. Conclusions Our findings suggest that CWS serving some communities with greater proportions of Hispanic and non-Hispanic Black residents have increased likelihood of detecting PFAS, including detection at levels above regulatory thresholds. These disparities are concerning and warrant consideration when planning remediation strategies and treatment for sites contaminated with PFAS. Keywords Community water systems, Environmental justice, Drinking water, Anthropogenic compounds, Disparities