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- Title
Field evidence of selenium bioreduction in a uranium-contaminated aquifer.
- Authors
Williams, Kenneth H.; Wilkins, Michael J.; N'Guessan, A. Lucie; Arey, Bruce; Dodova, Elena; Dohnalkova, Alice; Holmes, Dawn; Lovley, Derek R.; Long, Philip E.
- Abstract
Removal of selenium from groundwater was documented during injection of acetate into a uranium-contaminated aquifer near Rifle, Colorado ( USA). Bioreduction of aqueous selenium to its elemental form ( Se0) concentrated it within mineralized biofilms affixed to tubing used to circulate acetate-amended groundwater. Scanning and transmission electron microscopy revealed close association between Se0 precipitates and cell surfaces, with Se0 aggregates having a diameter of 50-60 nm. Accumulation of Se0 within biofilms occurred over a three-week interval at a rate of c. 9 mg Se0 m−2 tubing day−1. Removal was inferred to result from the activity of a mixed microbial community within the biofilms capable of coupling acetate oxidation to the reduction of oxygen, nitrate and selenate. Phylogenetic analysis of the biofilm revealed a community dominated by strains of Dechloromonas sp. and Thauera sp., with isolates exhibiting genetic similarity to the latter known to reduce selenate to Se0. Enrichment cultures of selenate-respiring microorganisms were readily established using Rifle site groundwater and acetate, with cultures dominated by strains closely related to D. aromatica (96-99% similarity). Predominance of Dechloromonas sp. in recovered biofilms and enrichments suggests this microorganism may play a role in the removal of selenium oxyanions present in Se-impacted groundwaters and sediments.
- Subjects
RIFLE (Colo.); SELENIUM &; the environment; URANIUM &; the environment; GROUNDWATER; AQUIFERS; TRANSMISSION electron microscopy
- Publication
Environmental Microbiology Reports, 2013, Vol 5, Issue 3, p444
- ISSN
1758-2229
- Publication type
Article
- DOI
10.1111/1758-2229.12032