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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

BOD20 (freshwater, non adapted) = 88% (BOD5=30%)
BOD14 (freshwater) = 73-94%
BOD20 (saltwater, non adapted) = 39%
BOD5 (freshwater, adapted) = 30%; BOD5 (freshwater, non adapted) = 7%
Primary degradation <= 1hour

Key value for chemical safety assessment

Additional information

A number of biodegradation studies have been carried out using both adapted and unadapted innoculii and in both fresh and saltwater. The key study clearly indicates that methoxyethanol is readily biodegradable in freshwater with non adapted bacterial populations. A supporting study indicates that primary degradation can be very rapid, occuring within hours. Other studies support this conclusion and also provide evidence that adapted bacteria degrade methoxyethanol much more rapidly than unadapted colonies. There is only a single study available in saltwater. This study was only performed over 20 days and indicated degradation of 39% over this timeframe with a non adapted innoculum. Degradation over 28 days may well reach 60% and it is not possible to reach a firm conclusion as to whether methoxyethanol is readily biodegradable from this study. However, the degradation is unlikely to fulfill the 10 day window requirement for ready biodegradation in salt water with unadapted bacteria. It is reasonable to conclude that in salt water, methoxyethanol is inherently biodegradable to unadapted bacteria but readily biodegradable to adapted bacteria