Multiple Dual C鈥揅l Isotope Patterns Associated with Reductive Dechlorination of Tetrachloroethene

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• 作者：Alice Badin ; G茅raldine Buttet ; Julien Maillard ; Christof Holliger ; Daniel Hunkeler
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：August 19, 2014
• 年：2014
• 卷：48
• 期：16
• 页码：9179-9186
• 全文大小：310K
• ISSN：1520-5851

文摘

Dual isotope slopes are increasingly used to identify transformation pathways of contaminants. We investigated if reductive dechlorination of tetrachloroethene (PCE) by consortia containing bacteria with different reductive dehalogenases (rdhA) genes can lead to variable dual C鈥揅l isotope slopes and if different slopes also occur in the field. Two bacterial enrichments harboring Sulfurospirillum spp. but different rdhA genes yielded two distinct 未¹³C to 未³⁷Cl slopes of 2.7 卤 0.3 and 0.7 卤 0.2 despite a high similarity in gene sequences. This suggests that PCE reductive dechlorination could be catalyzed according to at least two distinct reaction mechanisms or that rate-limiting steps might vary. At two field sites, two distinct dual isotope slopes of 0.7 卤 0.3 and 3.5 卤 1.6 were obtained, each of which fits one of the laboratory slopes within the range of uncertainty. This study hence provides additional insight into multiple reaction mechanisms underlying PCE reductive dechlorination. It also demonstrates that caution is necessary if a dual isotope approach is used to differentiate between transformation pathways of chlorinated ethenes.