Land cover as a predicative factor for PFAS occurrence in private drinking water samples

Per- and polyfluoroalkyl substances (PFAS) are synthetic organic compounds that are hydrophobic, thermally stable, and resistant to environmental degradation. Widespread use has resulted in frequent detection in the environment and drinking water, raising concerns about adverse human health effects. While PFAS are regulated in public drinking water systems, the estimated 36.8-56.5 million Americans relying on unregulated private drinking water remain comparatively understudied. This study investigates PFAS incidence in Virginia private drinking water and its association with land cover, point sources, household characteristics, and traditional water quality. Point-of-use samples (n=382) were collected from private wells across 10 Virginia counties and analyzed for 30 PFAS compounds using USEPA Methods 533 and 537.1. At least one PFAS compound was detectable in all samples, although median ΣPFAS concentrations were low (1.50 ppt). The USEPA MCL of 4 ppt was exceeded in 2.36% and 5.24% of samples for PFOA and PFOS, with a maximum ΣPFAS concentration of 303 ppt. High PFAS samples were associated with more anthropogenic activity, older wells, elevated lead levels, and corrosive water chemistry, suggesting both anthropogenic sources and potential in-home mobilization through plumbing. Exceedance of public water standards for lead (5.01%), E. coli (4.19%), and total coliform bacteria (34.8%) remained prevalent. Despite common use of water treatment devices, few households used systems capable of removing PFAS, heavy metals, or bacteria. These findings underscore ongoing risks for private well users and the need for expanded testing, effective treatment, and public awareness to reduce exposure to both emerging and long-standing drinking water contaminants.