Water Resources Research Act Program

Details for Project ID 2007ID73B

Selenium Biogeochemistry in the Hyporheic Zone of Streams within the Blackfoot River Watershed

Institute: Idaho
Year Established: 2007 Start Date: 2007-03-01 End Date: 2008-02-29
Total Federal Funds: $14,795 Total Non-Federal Funds: $33,553

Principal Investigators: Daniel Strawn, Gregory Moller, Matthew Morra

Project Summary: The Blackfoot River drainage basin encompasses a large part of the Western Phosphate Resource Area in Southeastern Idaho, and is a major tributary of the Snake River. As a result of phosphate mining activities over the last century the soils and waters in the drainage basin contain elevated concentrations of selenium, requiring active monitoring and management. However, bioavailability, water solubility, and toxicity of selenium are dependent on speciation, which is not well understood in sediments. There is ample evidence suggesting that sediments represent an important vector for selenium toxicity in the environment, and that geochemical reactions occurring in lotic sediments are important chemicals sources and sinks. Despite their recognized importance, there have been no direct studies on how environmental fluxes, e.g., pH, temperature, flow rate, and redox, impact the selenium speciation in the hyporheic zone. In this project the selenium biogeochemistry in the hyporheic zone of a first-order stream within the Blackfoot River watershed will be investigated. The stream has been identified as a selenium source within the watershed. Specific research objectives are to investigate the speciation and fractionation of selenium in stream sediment and surface waters so that the factors influencing the variability in water quality can be predicted. Experiments to achieve this objective will monitor pore and surface water geochemistry as a function of time and location. Results from this research will lead to better environmental management techniques (i.e., BMP, TMDL, and remediation strategies), and decreased risks to the ecosystem and water users in the watershed.