Stable Carbon Isotope Fractionation during Enhanced In Situ Bioremediation of Trichloroethene
详细信息 查看全文
- 作者：Donald L. Song ; Mark E. Conrad ; Kent S. Sorenson ; and Lisa Alvarez-Cohen
- 刊名：Environmental Science & Technology
- 出版年：2002
- 出版时间：May 15, 2002
- 年：2002
- 卷：36
- 期：10
- 页码：2262 - 2268
- 全文大小：153K
- 年卷期：v.36,no.10(May 15, 2002)
- ISSN：1520-5851
文摘
Time-series stable carbon isotope monitoring of volatileorganic compounds (VOCs) at the Idaho National Engineeringand Environmental Laboratory's (INEEL) field site TestArea North (TAN) was conducted during a pilot study toinvestigate the treatment potential of using lactate to stimulatein situ biologic reductive dechlorination of trichloroethene(TCE). The isotope ratios of TCE and its biodegradationbyproducts, cis-dichloroethene (c-DCE), trans-dichloroethene(t-DCE), vinyl chloride (VC), and ethene, in groundwatersamples collected during the pilot study were preconcentratedwith a combination of purge-and-trap and cryogenictechniques in order to allow for reproducible isotopicmeasurements of the low concentrations of these compoundsin the samples (down to 0.04 
M, or 5 ppb, of TCE). Compound-specific stable isotope monitoring of chlorinated solventsclearly differentiated between the effects of groundwatertransport, dissolution of DNAPL at the source, andenhanced bioremediation. Isotope data from all wellswithin the zone of lactate influence exhibited large kineticisotope effects during the reduction of c-DCE to VC andVC to ethene. Despite these large effects, the carbon isotoperatio of ethene in all these wells reached the carbonisotope ratios of the initial dissolved TCE, confirming thecomplete conversion of dissolved TCE to ethene. Conversely,the carbon isotope ratios of t-DCE were only marginallyaffected during the study, indicating that minimal biologicdegradation of t-DCE was occurring.
M, or 5 ppb, of TCE). Compound-specific stable isotope monitoring of chlorinated solventsclearly differentiated between the effects of groundwatertransport, dissolution of DNAPL at the source, andenhanced bioremediation. Isotope data from all wellswithin the zone of lactate influence exhibited large kineticisotope effects during the reduction of c-DCE to VC andVC to ethene. Despite these large effects, the carbon isotoperatio of ethene in all these wells reached the carbonisotope ratios of the initial dissolved TCE, confirming thecomplete conversion of dissolved TCE to ethene. Conversely,the carbon isotope ratios of t-DCE were only marginallyaffected during the study, indicating that minimal biologicdegradation of t-DCE was occurring.