Investigation of Household Drinking Water Sources and Contaminant Exposures in the Navajo Nation, 2008–2009

S-30B9-1 Background/Aims: Approximately 30% of households on Navajo Nation are currently not connected to a public water system. These households must transport or “haul” drinking water from outside water sources that are often unregulated and may contain dangerous chemical or bacterial contaminants. The objectives of this study were to identify whether Navajo households haul drinking water from contaminated water sources, examine contaminant levels in humans, and define community health risks. Methods: We conducted a cross-sectional survey of 296 households (with and without access to community water) that were randomly selected from 5 Navajo Nation communities in the state of New Mexico. Questionnaire data were collected regarding water use and hauling practices from selected participants. Laboratory analysis included testing for chemical and bacterial contaminants in drinking water as well as chemical contaminant levels in urine including uranium, arsenic, and cadmium. Results: Of 296 water samples collected, 33 (11%) samples exceeded safe drinking water standards for arsenic and 6 (2%) samples exceeded safe water standards for uranium. Ninety-four (33%) of the drinking water samples tested positive for total coliform bacteria and 23 (8%) tested positive for E. coli. Of the 244 urine samples collected, 93 (39%) had elevated uranium levels (>95% of levels seen in the US population as defined by National Health and Nutrition Examination Survey). Conclusion: The study population had unusually high urine uranium levels, though only a few water samples exceeded the EPA standard for uranium. Uranium contamination of drinking water sources does not appear to be the primary cause of increased uranium levels found in urine. Bacterial contamination levels were significantly higher in hauled water samples indicating a public health risk.