12/02/2009
New Technique for Studying Biogeochemical Transformation on Uranium
The Science
Understanding the fate and transport of uranium in subsurface environments is a major concern for planning remediation of contamination at the DOE cleanup sites. Yet it is very difficult to study the biogeochemical processes that impact uranium mobility in these environments. Research at the Argonne National Laboratory has now led to a realistic laboratory-based approach that uses sediments from field contaminated locations in microcosms prepared and maintained under conditions that closely match those in the field. Tests of the new technique were carried out using sediment samples from the Oak Ridge National Laboratory Integrated Field-Research Challenge site. The microcosms were maintained under anaerobic (no oxygen) conditions to ensure that microbial activity would match that in the sampled subsurface field site. Changes in chemical characteristics of the uranium in each microcosm were determined periodically over an eleven month period using x-ray absorption spectroscopy beamlines at the Advanced Photon Source. Analysis of the results of these experiments, along with biochemical and geochemical data, indicates that at least two distinct processes are taking place that gradually transform the highly mobile uranium (VI) to highly immobile uranium (IV).
BER Program Manager
Amy Swain
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Biological Systems Science Division
[email protected]
References
Kelly, S. D., W.-M. Wu, F. Yang, C. S. Criddle, T. L. Marsh, E. J. O’Loughlin, B. Ravel, D. Watson, P. M. Jardine, and K. M. Kemner. 2010. “Uranium Transformations in Static Microcosms,” Environmental Science and Technology 44(1), 236-242. DOI:10.1021/es902191s.