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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Ready biodegradable: 69 - 71% in 28 days (OECD 301B)

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Two studies investigating the ready biodegradability of the test substance are available - 1 key study plus 1 supporting study. One test was performed according to GLP and OECD guideline 301B using domestic non-adapted activated sludge as inoculum. The relative biodegradation values calculated from the measurements performed in duplicate during the test period revealed 69 and 71 % biodegradation of the test substance, respectively. The 10-day window was not met. According to “OECD Guidelines for the testing of chemicals – Revised introduction to the OECD guidelines for testing of chemicals, Section 3 – Part 1: Principles and strategies related to the testing of degradation of organic chemicals degradation” published by OECD (2006) the ready biodegradability data for mixtures should be evaluated carefully. For substances with different chain lengths the 10-day window should not be used for the interpretation of the results. It is possible that a sequential biodegradation took place which might have led to a prolonged lag-Phase and therefore a slower biodegradation period although the test substance was substantially biodegraded after the test duration. In this case the pass level can be applied at 28 days. The test substance was biodegraded 69 - 71% after 28 days. Therefore, the test substance is readily biodegradable. A second, non-GLP supporting study was performed using the OECD 301D set-up and demonstrated 90% biodegradation by Day 28 has been reported and confirms the Readyily Biodegradable status of the test substance.

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