ABSTRACT
Under anaerobic conditions existing in landfills, aquifers, or sediment, one is likely to find 1,2-dichloroethylenes that are formed as breakdown products from the reductive dehalogenation of common industrial solvents trichloroethylene, tetrachloroethylene, and 1,1,2,2-tetrachloroethane. The cis-1,2-dichloroethylene is apparently the more common isomer found, although it is often mistakenly reported as the trans isomer. If released into water, it will be lost mainly through volatilization. The results with respect to aerobic biodegradation in water are ambiguous, since some authors found 1,2-dichloroethylene to be recalcitrant while others found it to be biodegradable. Because it is relatively long-lived in the atmosphere, considerable dispersal from sources of emission should occur. This has resulted in monitoring reports erroneously listing the trans isomer when the cis isomer may be present.
