57Fe-Mossbauer studies of sediment cores from Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado
EMSL Project ID
34002
Abstract
The U.S. DOE faces the challenge of cleaning up and/or monitoring large, dilute plumes contaminated by metals, such as U, Tc, Pu, Hg, Cr, etc, whose mobility and solubility change with aquifer redox status. At the Uranium Mill Tailings Site (UMTRA) in Rifle, CO, field-scale experiments with acetate as electron donor have stimulated metal reducing bacteria to remove soluble U(VI) from the groundwater. The shallow depth to groundwater (3-4 m), thin saturated zone (~2.5 m), and well-defined groundwater flow at the site facilitated the monitoring of microbial and geochemical processes which led to following important findings: a) initial loss of U(VI) from the groundwater is coincident with an enrichment in Geobacter species (a Fe-reducer), and b) rebound in soluble U(VI) on an apparent switch of the aquifer from Fe-reducing to sulfate reducing conditions with simultaneous precipitation of Fe-sulfide phases of unknown nature. The purpose of the EMSL proposal is to take advantage of 57Fe-specific Mossbauer spectroscopy technique to primarily investigate Fe-mineralogy of sediment cores obtained from the field site under various biostimulated conditions to gain insights into Fe-mineral (bio)transformation and its implications on long-term U(VI) removal from the groundwater. Understanding this and behavior of site-specific, geochemical, and microbiological conditions is critical to the design of optimal biostimulation strategies for prolonging uranium bioremediation.
Project Details
Start Date
2009-03-02
End Date
2012-03-04
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Campbell KM, RK Kukkadapu, N Qafoku, AD Peacock, E Lesher, KH Williams, JR Bargar, MJ Wilkins, LA Figueroa, J Ranville, J Davis, and PE Long. 2012. "Geochemical, mineralogical and microbiological characteristics of sediment 1 from a naturally reduced zone in a uranium-contaminated aquifer." Applied Geochemistry.
Kukkadapu RK, N Qafoku, BW Arey, CT Resch, and PE Long. 2010. "Effect of Extent of Natural Subsurface Bioreduction on Fe-mineralogy of Subsurface Sediments." Journal of Physics: Conference Series 217(1):012047 1-8. doi:10.1088/1742-6596/217/1/012047
Moon HS, L McGuinness, RK Kukkadapu, AD Peacock, J Komlos, Jr., L Kerkhoff, PE Long, and PR Jaffe. 2010. "Microbial Reduction of Uranium under Iron- and Sulfate-reducing Conditions: Effect of Amended Goethite on Microbial Community Composition and Dynamics." Water Research 44(14):4015-4028.
Qafoku N, BN Gartman, RK Kukkadapu, BW Arey, KH Williams, PJ Mouser, SM Heald, JR Bargar, N Janot, SB Yabusaki, and PE Long. 2014. "Geochemical and Mineralogical Investigation of Uranium in Multi–element Contaminated, Organic–rich Subsurface Sediment ." Applied Geochemistry. doi:10.1016/j.apgeochem.2013.12.001
Qafoku N, RK Kukkadapu, JP McKinley, BW Arey, SD Kelly, CM Wang, CT Resch, and PE Long. 2009. "Uranium in Framboidal Pyrite from a Naturally Bioreduced Alluvial Sediment ." Environmental Science & Technology 43(22):8528-8534 . doi:10.1021/es9017333