Contrasting carbon isotope fractionation during biodegradation of trichloroethylene and toluene: Implications for intrinsic bioremediation

In experiments involving anaerobic biodegradation of trichloroethylene (TCE), δ13C values for residual TCE changed from −30.4‰ to values more enriched than −16‰. All data exhibit a consistent correlation between δ13C value of the residual TCE and the extent of biodegradation of TCE, described by a fractionation factor (α) of 0.9929. In contrast, during aerobic biodegradation of toluene by two separate mixed consortia, no change in δ13C value of …