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Uranium and Radon in Private Bedrock Well Water in Maine: Geospatial Analysis at Two Scales

[Image: see text] In greater Augusta of central Maine, 53 out of 1093 (4.8%) private bedrock well water samples from 1534 km(2) contained [U] >30 μg/L, the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) for drinking water; and 226 out of 786 (29%) samples from 1135 k...

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Detalles Bibliográficos
Autores principales: Yang, Qiang, Smitherman, Paul, Hess, C. T., Culbertson, Charles W., Marvinney, Robert G., Smith, Andrew E., Zheng, Yan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2014
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993615/
https://www.ncbi.nlm.nih.gov/pubmed/24655434
http://dx.doi.org/10.1021/es405020k
Descripción
Sumario:[Image: see text] In greater Augusta of central Maine, 53 out of 1093 (4.8%) private bedrock well water samples from 1534 km(2) contained [U] >30 μg/L, the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) for drinking water; and 226 out of 786 (29%) samples from 1135 km(2) showed [Rn] >4,000 pCi/L (148 Bq/L), the U.S. EPA’s Alternative MCL. Groundwater pH, calcite dissolution and redox condition are factors controlling the distribution of groundwater U but not Rn due to their divergent chemical and hydrological properties. Groundwater U is associated with incompatible elements (S, As, Mo, F, and Cs) in water samples within granitic intrusions. Elevated [U] and [Rn] are located within 5–10 km distance of granitic intrusions but do not show correlations with metamorphism at intermediate scales (10(0)−10(1) km). This spatial association is confirmed by a high-density sampling (n = 331, 5–40 samples per km(2)) at local scales (≤10(–1) km) and the statewide sampling (n = 5857, 1 sample per 16 km(2)) at regional scales (10(2)–10(3) km). Wells located within 5 km of granitic intrusions are at risk of containing high levels of [U] and [Rn]. Approximately 48 800–63 900 and 324 000 people in Maine are estimated at risk of exposure to U (>30 μg/L) and Rn (>4000 pCi/L) in well water, respectively.