Mesoscale Biotransformations of Uranium: Identifying Sites and Strategies where Reductive Immobilization is Practical
Bioreduction of U in contaminated sediments is an attractive strategy because of its low cost, and because of short-term studies supporting its feasibility. However, any in-situ immobilization approach for U will require assurance of either permanent fixation, or of very low release rates into the biosphere. Our previous long-term (2 years) laboratory experiments have shown that organic carbon (OC) based U(VI) bioreduction to UO2 can be transient even under sustained reducing (methanogenic) conditions. The biogeochemical processes underlying this finding urgently need to be understood. The current research is designed to identify mechanisms responsible for anaerobic U oxidation, and identify conditions that will support long-term stability of bioreduced U. We are investigating: (1) effects of OC concentration and supply rate on remobilization of bioreduced U, (2) the roles of Fe- and Mn-oxides as potential U oxidants in sediments, and (3) the role of microorganisms in U reoxidation, and (4) influences of pH on U(IV)/U(VI) redox equilibrium.
- Research Organization:
- DOEEMSP (USDOE Office of Environmental Management Science Program)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- OSTI ID:
- 896199
- Report Number(s):
- ERSD-1024940-2006; R&D Project: ERSD 1024940; TRN: US0700702
- Country of Publication:
- United States
- Language:
- English
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