ABSTRACT
The use of compound-specific isotope analysis is a promising new tool to assess bio-degradation of organic contaminants in groundwater. This presentation discusses the application of the method for sites contaminated by chlorinated solvents. Microcosm studies revealed that a large carbon isotope fractionation occurs during reductive dechlorination of trichloroethene (TCE) and aerobic mineralization of 1,2-dichloroethene (1,2-DCA). As a result, the remaining fraction of contaminant becomes increasingly enriched in 13C as biodegradation proceeds. At field sites, similar isotopic patterns as in the laboratory studies were found confirming that compound-specific isotope analysis can be used to monitor biodegradation of chlorinated solvents in groundwater.
