Arsenic in US correctional facility drinking water, 2006-2011

Background: Little is known about the quality of drinking water in US correctional facilities (e.g. detention centers, prisons, jails, etc.). Our objective was to determine if incarcerated persons are at risk for chronic, elevated arsenic exposure relative to the non-incarcerated US population, particularly in the Southwestern US where public water and groundwater arsenic concentrations are high compared to the rest of the US. Methods: We analyzed 230,158 arsenic monitoring records from 37,086 community water systems (CWSs) from the Environmental Protection Agency's (EPA) Third Six Year Review of Contaminant Occurrence dataset (covering 2006-2011). We compared six-year average arsenic concentrations and the odds of exceeding the EPA's 10 mu g/L maximum contaminant level (MCL) for CWSs exclusively serving correctional facilities versus all other CWSs in the Southwestern US, where groundwater arsenic concentrations are high. Results: Average six-year water arsenic concentrations were higher for Southwestern correctional facility CWSs (6.41 mu g/L, 95% CI 3.48, 9.34) compared to all other Southwestern CWSs (3.11 mu g/L, 95% CI 2.97, 3.24) and to other CWSs across the rest of the US (1.39 mu g/L, 95% CI 1.35, 1.42). In the Southwest, 26.1% (N = 6) of correctional facility CWSs versus 5.8% (509) of other CWSs reported six-year arsenic averages exceeding 10 mu g/ L, corresponding to an odds ratio of 5.70 (95% confidence interval 2.24, 14.52). Correctional facility CWSs in the Southwest were also more likely to report six-year averages exceeding 5 mu g/L (the MCL for New Jersey and New Hampshire, N = 8, odds ratio 2.77, 95% CI 1.17, 6.54). Discussion: Persons incarcerated in the Southwestern US were at disproportionate risk of elevated drinking water arsenic exposure and related disease from 2006 to 2011. Strict enforcement of EPA regulations and additional technical and financial support for CWSs serving correctional facilities in the Southwest is necessary to protect the health and human rights of incarcerated persons.