THE CROW WATER QUALITY COLLABORATION, A COMMUNITY-BASED PARTICIPATORY RESEARCH PROJECT, FINDS ELEVATED URANIUM IN WELLS ON THE CROW RESERVATION IN SOUTHCENTRAL MONTANA

Data from the Montana Bureau of Mines and Geology Ground Water Information Center (GWIC) and USGS National Uranium Resource Evaluation (NURE) database showed several wells with elevated uranium on the Crow Reservation in southcentral Montana. Many Reservation wells are in shallow Pleistocene deposits; most were not tested for uranium at the time the Indian Health Service had the wells drilled. On learning about the occurrence of uranium in groundwater - and also knowing about the abandoned uranium vanadium mines in the Pryor and Big Horn Mountains adjacent to the Reservation - the Crow Water Quality Project decided to include uranium in its home well water testing. Residents from throughout the Reservation volunteered to participate, completing a survey about their water usage and receiving a complete domestic analysis of their home well water. Uranium was tested in water from 99 wells (~10% of Tribal homes with wells). More than 2/3 tested positive for uranium, at levels exceeding the EPA’s Maximum Contaminant Level Goal of 0 μg/L; about 8% of wells tested exceeded EPA’s Maximum Contaminant Level of 30 μg/L. Uranium contamination is highest in the Big Horn River Valley, where it is significantly correlated with high total dissolved solids (p < 0.001; R² = 0.828). The cumulative risk from uranium, manganese and nitrates exceeds 1.0, the level of concern, for the entire Reservation portion of the Big Horn River Valley. Of the residents surveyed who do not drink their poor quality well water, 50% of them still cook with it; these families are most at risk for uranium exposure. An explanation of test results and the health risks of elevated uranium were provided to participating homeowners both in print and in person. The project is a community-based participatory research initiative of Little Big Horn College (the Tribal College for the Reservation), the Crow Tribe, the Apsaalooke [Crow] Water and Wastewater Authority, the local Indian Health Service Hospital and other local stakeholders, with support from academic partners at MSU Bozeman and the University of New England. Funding is being sought for additional well water testing, including for other radionuclides and selenium. Continued risk communication and risk mitigation with residents of the Crow Reservation are warranted.