Estimating the Occurrence of Arsenic in Residential Drinking Water and Population with Potential High Arsenic Exposure in Texas

Abstract

BACKGROUND AND AIM: Exposure to arsenic from drinking water raises a public health issue due to its prevalence and potential health effects. The purpose of this study was to assess the occurrence of arsenic levels in residential drinking water and estimate the population potentially exposed to high arsenic levels from consuming drinking water in Texas. METHODS: Data of arsenic testing in both public water systems (PWS) and domestic wells in 254 Texas counties were obtained from the Texas Commissions of Environmental Quality and the Texas Water Development Board to estimate the average arsenic concentration and number of populations potentially exposed to levels above the maximum contamination level (MCL), 10 µg/L over last 10 years. Additionally, the logistic regression model was fitted to estimate the odds of exceeding an MCL by region, water source, well depth, aquifer type, and social vulnerability index. RESULTS:In PWS, 2% of the sites had arsenic over an MCL with a maximum average level of 83.8 µg/L. The odds of an MCL violation were significantly higher in water systems sourced from groundwater and in rural and socially vulnerable areas. However, in private wells, 9.2% of the wells showed water arsenic levels greater than an MCL with average levels up to 569 µg/L. The wells 50-200 feet in depth, sourced from Ogallala and Gulf Coast Aquifers, and in socially vulnerable areas showed significantly higher detections of arsenic levels greater than the MCL. It was estimated that 323,741 people in 74 counties were potentially exposed to arsenic in residential drinking water over the MCL. CONCLUSIONS:Our results facilitated the evaluation of the current arsenic contamination in drinking water and the identification of areas of potential high arsenic exposure. Broader water screening and biomonitoring to determine the burden of arsenic exposure are required to protect public health in these areas. KEYWORDS: Arsenic, Drinking Water, Water Quality, Environmental Health