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Arsenic Drinking Water Violations Decreased Across the United States Following Revision of the Maximum Contaminant Level.
Citation:
Foster, S., M. Pennino, J. Compton, S. Leibowitz, AND M. Kile. Arsenic Drinking Water Violations Decreased Across the United States Following Revision of the Maximum Contaminant Level. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 53(19):11478-11485, (2019). https://doi.org/10.1021/acs.est.9b02358
Impact/Purpose:
Arsenic poses a threat to public health due to widespread environmental prevalence and known carcinogenic effects. It is important to know whether public water systems that violate the arsenic maximum contaminant level (MCL) have been increasing or decreasing over time in response to changes in regulations, to better protect human health. The analysis demonstrates the effectiveness of the new, lower standard for arsenic in reducing potential arsenic exposures to approximately a million people across the US during the last decade. Considering that other studies have shown decreased urinary arsenic levels in the population served by public water systems since the new standard, it may be inferred that the FAR is facilitating reduction of arsenic exposure in the US. The results of this study can help regulators and managers pinpoint not only know what systems are in violation but what regions, states, or counties have the most persistent arsenic problems so that improvements in technology or source water protection measures can be implemented. The results of this study could be important for a number of programs within EPA’s Office of Groundwater and Drinking Water, Regions, and States. This paper was an outgrowth of EPA R-authority post-doc Michael Pennino’s work with the Safe Drinking Water Information System (SDWIS) violations database. EPA-ORD was approached by Dr. Molly Kile in the College of Public Health and Human Sciences at Oregon State University to assist them on this analysis. Stephanie Foster, a PhD student with Dr. Kile at OSU, conducted this research as a student volunteer at EPA.
Description:
Arsenic poses a threat to public health due to widespread environmental prevalence and known carcinogenic effects. In 2001, the US EPA implemented the Final Arsenic Rule (FAR) for public drinking water, reducing the maximum contaminant level (MCL) from 50 g/L to 10 g/L. We investigated impacts of the FAR on drinking water violations temporally and geographically using the Safe Drinking Water Information System. Violations exceeding the MCL and the population served by violating systems were analyzed across the conterminous US from 2006 (onset of FAR enforcement) to 2017. The percentage of public water system violations declined from 1.3% in 2008 to 0.55% in 2017 (p < 0.001, slope= -0.070), and the population served decreased by over 1 million (p<0.001, slope = -106,886). Geographical analysis demonstrated higher mean violations and populations served were concentrated in certain counties rather than evenly distributed across states. The decline in violations is likely due to adoption of documented and undocumented treatment methods, and possibly from reduced environmental releases. Considering other studies have shown decreased urinary arsenic levels in the population served by public water systems since the new standard, it may be inferred that the FAR is facilitating reduction of arsenic exposure in the US.
URLs/Downloads:
DOI: Arsenic Drinking Water Violations Decreased Across the United States Following Revision of the Maximum Contaminant Level.