Influence of Speciation on the Transport of U(VI) through Hanford Sediments
EMSL Project ID
23598
Abstract
Uranium(VI) in the subsurface at the Department of Energy's (DOE) Hanford site poses a significant risk to the quality of the Columbia River and to future populations. Coupled hydrological and geochemical processes influencing the migration of U(VI) in subsurface sediments are not readily predicted using our current knowledge base. Results from our current ERSP project have identified significant differences in the transport of U(VI) in natural, heterogeneous samples from the Hanford flood deposits. The goal of the proposed research is to determine the relationship between geochemical speciation and the transport of U(VI). We hypothesize that geochemical heterogeneities, such as calcite and the amount of dissolved calcium, within the Hanford deposits exert the primary control upon U(VI) speciation and therefore on observed U(VI) transport. We propose a set of simple column experiments in homogenous repacked media containing varying amounts of calcite and dissolved calcium in order to quantify U(VI) transport parameters. We will link observed transport, geochemical speciation modeling, and spectroscopic analysis using cryogenic laser-induced fluorescence spectroscopy at EMSL. Subsequently, we will test the applicability of these results to the natural heterogeneous samples by determining U(VI) speciation and relating it to observed transport. Our research will enable prediction of the relationship between U(VI) speciation and transport based upon the geochemistry and mineralogy of a sedimentary layer. Our results will help ERSP meet its long-term measure to allow DOE to incorporate coupled biological, chemical, and physical processes into decision making for environmental remediation and long-term stewardship at former production facilities.
Project Details
Project type
Exploratory Research
Start Date
2008-04-01
End Date
2008-03-23
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members