Integrated Field-Scale Subsurface Research Challenge:
Rifle, Colorado
Microbiological, Geochemical Factors Controlling Uranium Mobility
Pacific Northwest National Laboratory (PNNL) is leading a field study at a uranium mill tailings site in Rifle, Colorado, to identify new approaches and strategies to help resolve questions about the movement of subsurface and contaminants.
The study is part of the U.S. Department of Energy's (DOE's) Integrated Field-Scale Subsurface Research Challenge, a new program that commits multi-investigator teams to performing large, benchmark-type experiments on formidable field-scale science issues. The field sites will provide capabilities to collect, permit and ship environmental samples of different types to other program investigators and provide site access to those interested in testing specific concepts or technologies/techniques relevant to the study of subsurface contaminant fate and transport.
The program is managed by DOE's Office of Biological and Environmental Research's Environmental Remediation Sciences Division. The Rifle Field Study involves examining the stimulation of subsurface microorganisms aimed at reducing and immobilizing uranium in the subsurface. At the uranium mill tailings site in Colorado, PNNL geohydrologist Phil Long leads a diverse team. Researchers have found that bioremediation of uranium is possible, but optimal control and manipulation of the process is still unknown.
"Understanding this process for controlling uranium mobility is critical in designing an effective bioremediation effort," says Long. "We hope to understand the microbial factors and the associated geochemistry that is controlling uranium movement, so that DOE can confidently remediate the uranium plumes. "Our approach should lead to new knowledge that can then be used to develop effective flow and reactive transport models."
Researchers look forward to initial analysis of microbial protein expression during field-scale bioremediation. These data will make it possible to learn what nutrient factors are most important for achieving maximum rates of uranium reduction and removal from groundwater.