Racial and ethnic disparities in community drinking water quality: a five-state assessment

Abstract

BACKGROUND AND AIM: Drinking water quality in the U.S has been a growing concern for decades. There is substantial evidence of regulatory violations and the presence of chemical and microbial contaminants that are detrimental to public health in drinking water supplies, but research on water quality disparities is limited. Here, we examined the water quality and demographic characteristics of populations served by community water systems (CWS) in five states: California (CA), New Jersey (NJ), North Carolina (NC), Pennsylvania (PA), and Texas (TX). METHODS: Water quality data for community water systems (CWS) were obtained from the EWG’s Tap Water Database for 2010-2017. State specific CWS service area boundaries were overlaid with census tract areas allowing community demographics to be linked to water quality data. Demographic characteristics of the CWS-served population were estimated by proportionally assigning census tract demographic data to the CWS by area and summing across that system. The overall water quality metrics were examined against the racial and ethnic groups served and stratified by system size. Water quality was estimated as a function of the average concentrations of major contaminants: nitrate, arsenic (As), trihalomethanes (THM4), and the cumulative cancer risk (CCR) due to 23 carcinogenic drinking water contaminants. RESULTS:CWS that served proportionally more Hispanic people, regardless of system size, in CA and TX had the overall highest average concentration of nitrates. For NJ, PA, and NC, there were racial/ethnic disparities in the average concentration of As, nitrate, and THM4 in drinking water served by different system sizes. The average CCR also differed across states with risk ranging from 1 X 10-4 to 9 X 10-4. CONCLUSIONS:This study findings indicate the need for federal, state, and local agencies to target racial and ethnic disparities in different regions and communities while seeking solutions to chemical contamination in the U.S drinking water. KEYWORDS: Water quality, risk assessment, multi-pollutant, environmental disparities