Document Detail


Spatial and temporal distributions of Geobacter lovleyi and Dehalococcoides spp. during bioenhanced PCE-NAPL dissolution.
MedLine Citation:
PMID:  19368201     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The spatial and temporal distributions of multiple reductively dechlorinating bacteria were simultaneously assessed in a one-dimensional sand column containing a tetrachloroethene (PCE) nonaqueous phase liquid (NAPL) source and associated plume zones. The column was uniformly inoculated with a PCE-to-ethene dechlorinating microbial consortium that contained Dehalococcoides spp., Dehalobacter spp., and Geobacter lovleyi strain SZ. Geobacter and Dehalococcoides populations grew and colonized the column material, including the mixed-NAPL (0.25 mol/mol PCE in hexadecane) source zone. In contrast, Dehalobacter cells did not colonize the porous column material, and planktonic Dehalobacter cell titers remained below the detection limit of ca. 2.6 x 10(2) cells/mL throughout the experiment. Significant PCE dechlorination was observed and resulted in bioenhanced NAPL dissolution up to 21-fold (maximum) and 5.2-fold (cumulative) relative to abiotic dissolution. cis-1,2-Dichloroethene (cis-DCE) wasthe primary dechlorination product although vinyl chloride (VC) was also formed throughout the experiment. Ethene production occurred after significant depletion of PCE from the NAPL and when cis-DCE concentrations dropped below 6 microM. Data obtained after increasing the column residence time from 1.1 to 2.8 days and introducing a VC pulse to the column indicated that both the residence time and cis-DCE inhibition limited significant VC and ethene production. Although both Geobacter and Dehalococcoides cells were present and active in the mixed-NAPL source zone and plume region, Geobacter cell numbers were typically more than 1 order of magnitude higher than Dehalococcoides cell numbers, which is consistent with the production of predominantly cis-DCE. Analysis of both liquid- and solid-phase samples indicated that Geobacter cells grew and remained attached to the porous medium within the source zone but were largely planktonic in the plume region. In contrast Dehalococcoides cell were attached throughoutthecolumn,and Dehalococcoides cell titers increased by 1 to 2 orders of magnitude over the length of the column, correlating to increases in VC concentrations. The results from this study highlight that bioenhanced dissolution is governed by a complex interplay between resident dechlorinators, contaminant concentrations, and other aquifer-specific characteristics (e.g., hydrology).
Authors:
Benjamin K Amos; Eric J Suchomel; Kurt D Pennell; Frank E Löffler
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Environmental science & technology     Volume:  43     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-04-16     Completed Date:  2009-05-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1977-85     Citation Subset:  IM    
Affiliation:
School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Georgia 30332-0512, USA.
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MeSH Terms
Descriptor/Qualifier:
Bacteria / isolation & purification*
Biodegradation, Environmental
Tetrachloroethylene / chemistry*
Time Factors
Water Pollutants, Chemical / chemistry*
Chemical
Reg. No./Substance:
0/Water Pollutants, Chemical; 127-18-4/Tetrachloroethylene

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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