Abstract
At Department of Energy Site 300, beneficial hydrocarbon cocontaminants and favorable subsurface conditions facilitate sequential reductive dechlorination of trichloroethene (TCE) and rapid oxidation of the resultant cis-dichloroethene (cis-DCE) upon periodic oxygen influx. We assessed the geochemistry and microbial community of groundwater from across the site. Removal of cis-DCE was shown to coincide with oxygen influx in hydrocarbon-containing groundwater near the source area. Principal component analysis of contaminants and inorganic compounds showed that monitoring wells could be differentiated based upon concentrations of TCE, cis-DCE, and nitrate. Structurally similar communities were detected in groundwater from wells containing cis-DCE, high TCE, and low nitrate levels. Bacteria identified by sequencing 16S rRNA genes belonged to seven phylogenetic groups, including Alpha-, Beta-, Gamma- and Deltaproteobacteria, Nitrospira, Firmicutes and Cytophaga-Flexibacter- Bacteroidetes (CFB). Whereas members of the Burkholderiales and CFB group were abundant in all wells (104-109 16S rRNA gene copies L -1), quantitative PCR showed that Alphaproteobacteria were elevated (>106 L-1) only in wells containing hydrocarbon cocontaminants. The study shows that bacterial community structure is related to groundwater geochemistry and that Alphaproteobacteria are enriched in locales where cis-DCE removal occurs.
Original language | English (US) |
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Pages (from-to) | 299-311 |
Number of pages | 13 |
Journal | FEMS microbiology ecology |
Volume | 60 |
Issue number | 2 |
DOIs | |
State | Published - May 2007 |
Externally published | Yes |
Keywords
- Dichloroethene
- Diesel
- Tetraalkoxysilane
- Trichloroethylene
ASJC Scopus subject areas
- Microbiology
- Ecology
- Applied Microbiology and Biotechnology