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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Tetrachloroethylene was not biodegraded in a modified shake flask closed bottle biodegradation test after 21 days.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

The results of biodegradation screening tests are variable. Tetrachloroethylene is not readily biodegradable under the stringent conditions of a modified shake flask closed bottle biodegradation test. However, biodegradation occurs when tetrachloroethylene is incubated with bacterial cultures in the presence of another substrate such as methanol or formate or with adapted cultures. Futhermore, under anaerobic conditions tetrachloroethylene degrades by a process of reductive dehalogenation, i.e., sequential removal of halogens, resulting in transient intermediates. The terminal product is ethylene, which can be further reduced to ethane.