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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The substance is not readily biodegradable, but appears to show evidence of slow aerobic degradation that did not plateau before the end of a 28-day study.  An extended Modified OECD Screening test (OECD 301 F, EC C.4-D) demonstrated 98% degradation after 60 days, indicating a potential for complete mineralisation in the environment.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable, not fulfilling specific criteria

Additional information

Ready biodegradability was tested according to the Modified OECD Screening test (OECD 301 F, EC C.4-D) in 2010 by Harlan Laboratories Ltd. (Clarke N). The initial test substance concentration was 20 mg/L. The test was performed with predominantly domestic activated sewage sludge collected from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, and the oxygen consumption was monitored over a time period of 60 days. The test substance exhibited a slow but steady degradation rate that did not plateau before the end of the study on day 28, by which time 43% degradation (oxygen consumption) had occurred. Degradation reached 98% after 60 days. The reference substance, aniline, achieved 71% degradation after 14 days, 88% degradation aft 28 days, and 105% degradation after 60 days. The validity criteria were met, and the substance was considered not to be readily biodegradable under the conditions of the test, although the results do indicate a potential for complete mineralisation in the environment.

 

Ready biodegradability was tested according to the Modified OECD Screening test (OECD 301 E, EC C.4-B) in 1989 by Ciba-Geigy Ltd. (Bader U). The initial test substance concentration was equivalent to 20 mg DOC/L. The test was performed with mixed polyvalent bacteria collected from the secondary effluent of the domestic sewage treatment plant at CH-4106 Therwil, and the DOC removal was monitored over a time period of 28 days. The test substance exhibited a slow but steady degradation rate that did not plateau before the end of the study on day 28, by which time 38% degradation (DOC removal) had occurred. The reference substance, aniline, achieved 99% and 100% DOC removal after 7 days and 28 days, respectively. The validity criteria were met, and the substance was considered not to be readily biodegradable under the conditions of the test.

A supporting study conducted in accordance with the Modified MITI Test I (OECD 301 C, EU C.4-F) in 2002 is reported by the Japanese National Institute of Technology and Evaluation (NITE). Nominal initial test substance concentration was 100 mg/L, and the test was performed using 30 mg/L of activated sludge. The duration of the test was 4 weeks, after which the test substance had achieved a degradation of 5% measured by oxygen uptake and 9% measured by TOC removal. GC analysis showed 86% loss of the test substance over the course of the test, but the report states that hydrolysis [of the epoxy groups] had occurred. No data to confirm the validity of the test were reported. The test substance was reported to be persistent.