Bioremediation of Chlorinated Ethenes in Fractured Bedrock and Associated Changes in Dechlorinating and Nondechlorinating Microbial Populations

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• 作者：Alfredo P茅rez-de-Mora ; Anna Zila ; Michaye L. McMaster ; Elizabeth A. Edwards
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：May 20, 2014
• 年：2014
• 卷：48
• 期：10
• 页码：5770-5779
• 全文大小：495K
• 年卷期：v.48,no.10(May 20, 2014)
• ISSN：1520-5851

文摘

The use of enhanced in situ anaerobic bioremediation (EISB) and bioaugmentation in fractured bedrock is limited compared to its use in granular media. We evaluated EISB for the treatment of trichloroethene (TCE)-impacted groundwater in fractured carbonate rock at a site in Southern Ontario, Canada, with cool average groundwater temperature ( 13 掳C). Borehole-connectivity, contaminant concentrations, and groundwater properties were investigated. Changes in dechlorinating and nondechlorinating populations (fermenters, acetogens, methanogens, and sulfate reducers) were assessed via quantitative PCR (qPCR). During biostimulation with ethanol, concentrations of TCE daughter products cis-dichloroethene (cDCE) and vinyl chloride (VC) decreased in association with an enrichment of vcrA (VC reductive dehalogenase)-carrying Dehalococcoides, whereas ethene production was only moderate. Following bioaugmentation with the mixed dechlorinating culture KB-1, greater concentrations of chloride鈥攁 product of dechlorination鈥攚as observed in most wells; in addition, ethene production increased significantly in monitoring well locations that had strong hydraulic connectivity to the groundwater recirculation system, while Dehalococcoides and vcrA concentrations did not appreciably vary. Interestingly, increases of 3鈥? orders of magnitude of an ethanol-fermenting Bacteroidetes population also present in KB-1 were correlated to improved conversion to ethene, an observation which suggests there could be a causal relationship鈥攆or example, better syntrophy and/or synergy among bacterial populations.