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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Various information is available for TCE investigating the biodegradation in water, sediment and soil under certain conditions. It can be deduced from available data that degradation does not occure under stringent conditions of readily biodegradability test. Biodegradation is more pronounced under anaerobic conditions and in the presence of co-substates or with specific adapted cultures.

However, for assessment as a worst case EUSES degradation estimates calculated based on input parameter “not biodegradable” were used.

Additional information

A number of studies have been reported on the biodegradation of trichloroethylene, and the results of these biodegradation tests are variable.

Trichloroethylene is not readily biodegradable under the stringent conditions of the OECD (301D) and is only slightly degraded in aerobic studies.

However, trichloroethylene can be degraded under aerobic conditions by a process of co-oxidation when other suitable co-substrates (methane, propane, toluene, phenol) are also present to support growth of the microorganisms and induce the formation of enzymes which due to their broad substrate specificity, can also degrade trichloroethylene.

There is extensive work which shows that under anaerobic conditions, trichloroethylene degrades by a process of reductive dehalogenation, resulting in the formation of lower chlorinated homologues as reaction products. Although metabolites are known to occur, the terminal product of reductive dehalogenation is ethylene.

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