Per- and polyfluoroalkyl substances (PFASs) are a class
of toxic
organic compounds that have been widely used in consumer applications
and industrial activities, including oil and gas production. We measured
PFAS concentrations in 45 private wells and 8 surface water sources
in the oil and gas-producing Doddridge, Marshall, Ritchie, Tyler,
and Wetzel Counties of northern West Virginia and investigated relationships
between potential PFAS sources and drinking water receptors. All surface
water samples and 60% of the water wells sampled contained quantifiable
levels of at least one targeted PFAS compound, and four wells (8%)
had concentrations above the proposed maximum contaminant level (MCL)
for perfluorooctanoic acid (PFOA). Individual concentrations of PFOA
and perfluorobutanesulfonic acid exceeded those measured in finished
public water supplies. Total targeted PFAS concentrations ranged from
nondetect to 36.8 ng/L, with surface water concentrations averaging
4-fold greater than groundwater. Semiquantitative, nontargeted analysis
showed concentrations of emergent PFAS that were potentially higher
than targeted PFAS. Results from a multivariate latent variable hierarchical
Bayesian model were combined with insights from analyses of groundwater
chemistry, topographic characteristics, and proximity to potential
PFAS point sources to elucidate predictors of PFAS concentrations
in private wells. Model results reveal (i) an increased vulnerability
to contamination in upland recharge zones, (ii) geochemical controls
on PFAS transport likely driven by adsorption, and (iii) possible
influence from nearby point sources.