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Environ Sci Technol

Title:		Stable carbon isotope fractionation during enhanced in situ bioremediation of trichloroethene
Author(s):		Song DL; Conrad ME; Sorenson KS; Alvarez-Cohen L;
Address:		"Department of Civil and Environmental Engineering, Berkeley, California 94720-1710, USA"
Journal Title:		Environ Sci Technol
Year:		2002
Volume:		36
Issue:		10
Page Number:		2262 - 2268
DOI:		10.1021/es011162d
ISSN/ISBN:		0013-936X (Print) 0013-936X (Linking)
Abstract:		"Time-series stable carbon isotope monitoring of volatile organic compounds (VOCs) atthe Idaho National Engineering and Environmental Laboratory's (INEEL) field site Test Area North (TAN) was conducted during a pilot study to investigate the treatment potential of using lactate to stimulate in situ biologic reductive dechlorination of trichloroethene (TCE). The isotope ratios of TCE and its biodegradation byproducts, cis-dichloroethene (c-DCE), trans-dichloroethene (t-DCE), vinyl chloride (VC), and ethene, in groundwater samples collected during the pilot studywere preconcentrated with a combination of purge-and-trap and cryogenic techniques in order to allow for reproducible isotopic measurements of the low concentrations of these compounds in the samples (down to 0.04 microM, or 5 ppb, of TCE). Compound-specific stable isotope monitoring of chlorinated solvents clearly differentiated between the effects of groundwater transport, dissolution of DNAPL at the source, and enhanced bioremediation. Isotope data from all wells within the zone of lactate influence exhibited large kinetic isotope effects during the reduction of c-DCE to VC and VC to ethene. Despite these large effects, the carbon isotope ratio of ethene in all these wells reached the carbon isotope ratios of the initial dissolved TCE, confirming the complete conversion of dissolved TCEto ethene. Conversely, the carbon isotope ratios of t-DCE were only marginally affected during the study, indicating that minimal biologic degradation of t-DCE was occurring"
Keywords:		"Biodegradation, Environmental Carbon Isotopes/analysis Environmental Monitoring/*methods Ethylenes/chemistry Lactic Acid/metabolism Soil Microbiology Solvents/*metabolism Trichloroethylene/*metabolism Water Movements Water Pollutants, Chemical/*metabolism;"
Notes:		"MedlineSong, Donald L Conrad, Mark E Sorenson, Kent S Alvarez-Cohen, Lisa eng P42-ES04705/ES/NIEHS NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. 2002/06/01 Environ Sci Technol. 2002 May 15; 36(10):2262-8. doi: 10.1021/es011162d"