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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

 1,1-dichloroethene is considered as not readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

One reliable study performed according to the OECD test guideline 301 D (CITI 1992) is available. It showed no ultimate biodegradation of 1,1-dichloroethene after 28 days of incubation with activated sludge. Estimations made by the models BIOWIN 1, 2, 3, 5 and 6 support this conclusion. Therefore, 1,1-dichloroethene is considered as not readily biodegradable.

A biodegradability study with a domestic waste water inoculum (Tabak et al., 1981) showed by GC analysis and TOC determination a loss of 78% and 45% of 1,1-dichloroethene at initial concentrations of 5 and 10 mg/L respectively in 7 days. After a subsequent subculture of 7 days (adaptation) there was a loss of 100 % of 1,1-dichloroethene. Abiotic control showed that volatilization took place at a level of from 15 to 24% in 10 days. This study shows an important primary degradation of 1,1-dichloroethene in aerobic conditions.

The study by Fogel et al. (1986) and the estimation of BIOWIN model 7 show that biodegradation of 1,1-dichloroethene can occur under anaerobic conditions.