This publication received wide press coverage, featured in Newsweek, New York Post, and Phys.org.

A recent study published in Environmental Health Perspectives, featuring STEEP co-authors Jahred Liddie, PhD and Laurel Schaider, PhD, sought to evaluate the relationship between sociodemographic disparities and unregulated industrial contaminants in US public water systems (PWS).

Researchers gathered Environmental Protection Agency (EPA) data, PWS characteristics, sociodemographic data, and suspected pollution sources from regulatory databases. Contaminants measured were PFAS, 1,4-dioxane, 1,1-dichloroethane, and chlorodifluoromethane (HCFC-22), and detections were captured for each the four contaminants, detection of more than one target contaminant, and PWS exceedance of more than one EPA regulatory level in effect in 2017.

Research results found more than 97 million US residents were served by a PWS with detectable levels of 1,4-dioxane (22% of PWS), HCFC-22 (5.8%), 1,1-dichloroethane (4.7%), and/or PFAS (4.0%). Unregulated contaminant detection was more common in large systems, urban systems, and systems using groundwater or a combination of groundwater and surface water. PWS with detectable levels served counties with higher proportions of Hispanic residents (17% vs. 13% of undetected), as did PWS exceeding regulations (18% vs. 14% not exceeded). Positive associations were found between proportions of Hispanic residents and contamination, even after accounting for pollution sources.

Results demonstrated that previous research underestimated exposure because of the exclusion of unregulated contaminants. PWS serving more Hispanic residents, non-Hispanic Black residents, and urban households would benefit from additional resources about unregulated chemical contamination, and research should continue to evaluate factors to protect water quality for all residents.

Aaron J. Maruzzo, Amanda B. Hernandez, Christopher H. Swartz, Jahred M. Liddie, and Laurel A. Schaider. Socioeconomic Disparities in Exposures to PFAS and Other Unregulated Industrial Drinking Water Contaminants in US Public Water Systems. Environmental Health Perspectives 2025 Volume 133, Issue 1.