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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

As key study a GLP test according to OECD guideline 310 was identified using non-adapted domestic activated sludge as inoculum. In order to demonstrate biodegradability, the test duration was prolonged up to 60 days of exposure. After this exposure period, the substance was found to be biodegradable due 69% biodegradation related to TIC analysis.

Furthermore, four different studies can be taken into account for the assessment of the biodegradability of 2 -mercaptoethanol as supporting evidence. Two test on ready biodegradability as well as one test on inherent and one test on anaerobic biodegradability are available The first study on ready biodegradability is a GLP-test according to OECD TG 301A performed by Elf Atochem S.A. (1994) using secondary effluent from a municipal sewage treatment plant. The second test was performed by MITI Japan (1992) according to OECD TG 301C using mixed inoculum according to MITI Japan. After 28 days they showed biodegradation rates of < 10% (DOC removal) and 15 -21% (O2consumption), respectively. Regarding inherent biodegradation, a test performed by MITI Japan (1992) in an open system according to OECD TG 302C using mixed inoculum according to MITI is available. After 28d a TOC-removal of 90% was measured.