PFAS and Mixed Contaminant Exposure in Drinking Water: Assessing Human Health Risks Across Public and Private Water Systems

Per- and polyfluoroalkyl substances (PFAS) and complex organic-inorganic chemical mixtures increasingly co-occur in both public water systems and private wells, yet most exposure and risk assessments still treat PFAS in isolation. This narrow focus obscures the cumulative health risks faced by communities exposed to multiple contaminants simultaneously, particularly in underserved and rural areas where private wells fall outside routine regulatory monitoring and receive far less scrutiny than municipal supplies.Recent field-scale monitoring, including work documenting PFAS and mixed contaminants in tribal water supplies, has shown that exposure pathways and contamination sources vary substantially between public and private systems. Public systems are subject to periodic testing and treatment requirements, while private wells depend on individual owners for monitoring and remediation, a gap that leaves many vulnerable populations unaware of their own exposure levels. As a result, these communities often bear a disproportionate share of the resulting health burden, compounding existing environmental justice concerns. Bridging environmental monitoring data with human health risk assessment is essential to closing this gap and building a more complete picture of real-world, multi-contaminant exposure.The goal of this Research Topic is to advance the evaluation of human exposure pathways and cumulative health risks associated with PFAS and mixed organic-inorganic contaminants in public and private drinking water resources. It aims to bring together environmental chemists, hydrologists, exposure scientists, and epidemiologists to examine how contaminant mixtures move from source to tap, how point-of-consumption exposure differs between regulated and unregulated systems, and how cumulative risk models can better capture combined chemical burden rather than relying on single-contaminant thresholds. Particular emphasis is placed on environmental justice, including the exposure disparities affecting underserved, rural, and tribal communities that depend on private or under-monitored water sources. By connecting monitoring data, exposure modeling, and health outcomes, this collection aims to support more protective, equity-informed drinking water policy.This Research Topic explores:- How contaminant mixtures move from source to tap in both public water systems and private wells.- Differences in point-of-consumption exposure between regulated public systems and unregulated or under-monitored private systems.- Cumulative and mixture risk assessment methods that capture combined chemical burden rather than single-contaminant thresholds.- Field-scale and point-of-consumption monitoring approaches for PFAS and co-occurring organic-inorganic contaminants.- Exposure disparities affecting underserved, rural, and tribal communities that rely on private or under-monitored water sources.- Integration of environmental monitoring data with epidemiological and health-outcome frameworks.- Policy implications and recommendations for more protective, equity-informed drinking water standards.Original research, reviews, mini-reviews, and case studies. Interdisciplinary submissions bridging environmental chemistry, hydrology, exposure science, and public health are especially welcome. Topic editors: Kelly L Smalling, Paul Bradley Source: https://www.frontiersin.org/research-topics/85480/pfas-and-mixed-contaminant-exposure-in-drinking-water-assessing-human-health-risks-across-public-and-private-water-systems