Origin of a Mixed Brominated Ethene Groundwater Plume: Contaminant Degradation Pathways and Reactions

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• 作者：Bradley M. Patterson ; Elizabeth Cohen ; Henning Prommer ; David G Thomas ; Stuart Rhodes ; Allan J. McKinley
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：February 15, 2007
• 年：2007
• 卷：41
• 期：4
• 页码：1352 - 1358
• 全文大小：290K
• 年卷期：v.41,no.4(February 15, 2007)
• ISSN：1520-5851

文摘

On the basis of a combination of laboratory microcosmexperiments, column sorption experiments, and the currentspatial distribution of groundwater concentrations, theorigin of a mixed brominated ethene groundwater plumeand its degradation pathway were hypothesized. Thecontaminant groundwater plume was detected downgradientof a former mineral processing facility, and consisted oftribromoethene (TriBE), cis-1,2-dibromoethene (c-DBE), trans-1,2-dibromoethene (t-DBE), and vinyl bromide (VB). Thecombined laboratory and field data provided strong evidencethat the origin of the mixed brominated ethene plumewas a result of dissolution of the dense non-aqueous-phase liquid 1,1,2,2-tetrabromoethane (TBA) at the presumedsource zone, which degraded rapidly (half-life of 0.2days) to form TriBE in near stoichiometric amounts. TriBEthen degraded (half-life of 96 days) to form c-DBE,t-DBE, and VB via a reductive debromination degradationpathway. Slow degradation of c-DBE (half-life >220days), t-DBE (half-life 220 days), and VB (half-life >220days) coupled with their low retardation coefficients (1.2,1.2, and 1.0 respectively) resulted in the formation of anextensive mixed brominated ethene contaminant plume.Without this clearer understanding of the mechanism forTBA degradation, the origin of the mixed brominated ethenegroundwater contamination could have been misinterpreted,and inappropriate and ineffective source zone andgroundwater remediation techniques could be applied.