Determination of the 13C/12C Isotope Ratio of Organic Compounds for the Biological Degradation of Tetrachloroethene (PCE) and Trichloroethene (TCE)

With the method used here, it was possible to determine the isotope content of both the initial compounds and their metabolites formed due to microbial degradation. The chemical analysis showed that the dominating degradation metabolite for both PCE and TCE degradation was cis‐1,2‐dichloroethene (cis‐1,2‐DCE). Apart from this, the formation of TCE, trans‐1,2‐DCE, 1,1‐DCE, chloroethene (VC), ethene and ethane was observed. The isotope analysis showed no measurable fractionation of stable carbon isotopes, for the microbial degradation of PCE and TCE to cis‐1,2‐DCE. There was a small effect for trans‐1,2‐DCE and a stronger one for VC as metabolite of TCE.