Complex systems assessment of biogeochemical factors and microbial community members associated with naturally occurring uranium contamination in groundwater resources
Naturally occurring radionuclides, such as uranium, are present in low concentrations in many granitic geological formations in the northeast. Mineral dissolution processes, microbial activity, and changes in nutrient loading promotes the release of this toxic metal in groundwater aquifers that serve as public and private water supplies. Human consumption of groundwater containing elevated uranium and its radionuclide daughter product, radon, increases the risk of kidney damage and lung cancer due, respectively. Unfortunately, mechanisms controlling the in situ release and mobility of naturally-occurring uranium from bedrock materials is poorly understood, and must be addressed to limit human exposure and improve water quality in Maine The proposed study seeks to elucidate the possible microbially-mediated biogeochemical mechanisms associated with elevated levels of uranium in Maine groundwater using a complex systems approach. The proposed research involves: 1) analysis of groundwater biogeochemistry and microbial community profiles targeting the 16S rRNA gene from supply wells historically elevated in uranium, and 2) application of statistical and neural network models with combined biogeochemical data to identify potential drivers of mobilized uranium in the groundwater. Our findings will assist the Maine Geological Survey and Drinking Water Program in classifying areas at risk to elevated U exposure, identifying possible pollutant sources that might be stimulating microbial activity related to U mobilization, and developing management strategies for lowering U in supply wells.
Survey of groundwater uranium levels plotted with bedrock formations in
Maine. Green, orange, and peach colors are metamorphic rocks of all grades.
Image is courtesy of the Maine Geological Survey.
Civil & Environmental Engineering
5711 Boardman Hall
University of Maine, Orono, ME 04469
Image Description: groundwater survey map