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Assessment of biodegradation of chlorinated hydrocarbons in groundwater using stabel carbon and chlorine isotopes

English title Assessment of biodegradation of chlorinated hydrocarbons in groundwater using stabel carbon and chlorine isotopes
Applicant Hunkeler Daniel
Number 109666
Funding scheme Project funding (Div. I-III)
Research institution Centre d'hydrogéologie et de géothermie Université de Neuchâtel
Institution of higher education University of Neuchatel - NE
Main discipline Other disciplines of Environmental Sciences
Start/End 01.10.2005 - 30.09.2007
Approved amount 190'815.00
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Keywords (6)

stable istopes; chlorinated hydrocarbons; groundwater; biodegradation; Stable isotopes; chlorinated solvents

Lay Summary (English)

Lead
Lay summary
The project investigated the use of compound-specific carbon and chlorine isotope analysis to evaluate the degree and pathway of chlorinated ethene degradation in groundwater. In laboratory experiments it was demonstrated that aerobic oxidation of vinyl chloride (VC) is associated with a signifiantly smaller chlorine to carbon isotope fractionation than reductive dechlorination of VC and cis-1,2-dichloroethene because the former does not involve bond changes to chlorine in the initial transformation step. Field experiments at high resolution sites demonstrated that carbon isotope ratios provide detailed information on whether an intermediate compound accumulates or degrades further, while the combined carbon-chlorine isotope approach makes it possible to identify the mechanism of degradation. Finally a new mathematical approach was developed to derive degradation rates from isotope data of multistep processes that takes into account the effect of subsurface heterogeneity. In summary, the project demonstrated that the combined carbon and chlorine isotope approach provides detailed information on type and rate of processes affecting chlorinated ethenes and hence is a reliable indictor to assess natural attenuation and engineered remediation of chlorinated ethene contaminated sites.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
117860 Demonstrating a natural origin of chloroform in groundwater using stable isotope analysis 01.10.2008 Project funding (Div. I-III)
100538 Assessment of biodegradation of chlorinated hydrocarbons in groundwater using stabel isotopes and methods of molecular microbial ecology 01.10.2003 Project funding (Div. I-III)

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