Biological and Chemical Interactions with U(VI) During Anaerobic Enrichment in the Presence of Iron Oxide Coated Quartz

Journal Article · Tue Nov 01 04:00:00 EST 2005 · Water Research

DOI:https://doi.org/10.1016/j.watres.2005.09.004· OSTI ID:912247

Lee, Brady D; Walton, Michelle R; Megio, Jodette L

Microcosm experiments were performed to understand chemical and biological interactions with hexavalent uranium (U(VI)) in the presence of iron oxide bearing minerals and trichloroethylene (TCE) as a co-contaminant. Interactions of U(VI) and hydrous iron oxide moieties on the mineral oxide surfaces were studied during enrichments for dissimilatory iron reducing (DIRB) and sulfate reducing bacteria (SRB). Microbes enriched from groundwater taken from the Test Area North (TAN) site at the Idaho National Engineering and Environmental Laboratory (INEEL) were able to reduce the U(VI) in the adsorption medium as well as the iron on quartz surfaces. Early in the experiment disappearance of U(VI) from solution was a function of chemical interactions since no microbial activity was evident. Abiotic removal of U(VI) was enhanced in the presence of carbonate. As the experiment proceeded, further removal of U(VI) from solution was associated with the fermentation of lactate to propionate and acetate. During later phases of the experiment when lactate was depleted from the growth medium in the microcosm containing the DIRB enrichments, U(VI) concentrations in the solution phase increased until additional lactate was added. When lactate fermentation proceeded, U(VI) concentrations in the liquid phase again returned to near zero. Similar results were shown for the SRB enrichment but less uranium was released back into solution, while in the enrichment with carbonate uranium was not released back into solution. Chemical and biological interactions appear to be important on the mobilization/immobilization of U(VI) in an iron oxide system when TCE is present as a co-contaminant. Interestingly, TCE present in the microcosm experiments was not dechlorinated which was probably an effect of redox conditions that were unsuitable for reductive dechlorination by the microbial culture tested.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: DOE - EM
• DOE Contract Number: AC07-99ID13727
• OSTI ID: 912247
• Report Number(s): INEEL/JOU-03-01384
• Journal Information: Water Research, Journal Name: Water Research Journal Issue: 18 Vol. 39; ISSN 0043-1354; ISSN WATRAG
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ADSORPTION
Adsorption
BEARINGS
CARBONATES
DECHLORINATION
FERMENTATION
Groundwater
INEEL
IRON
IRON OXIDES
Iron-reducing bacteria
LACTATES
MICROCOSMS
Metal reduction
OXIDES
QUARTZ
REMOVAL
SULFATE-REDUCING BACTERIA
Sulfate reducing bacteria
URANIUM
Uranium