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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Biodegradation: 71% (28-days; 14-day window does not apply, OECD 2006) readily biodegradable, OECD301D, Akzo Nobel 2015

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

In order to assess the biotic degradation, a ready biodegradability test was performed which allows the biodegradability to be measured in an aerobic aqueous medium. The ready biodegradability was determined in the Closed Bottle test (OECD TG 301 D) performed according to slightly modified OECD, EU and ISO Test Guidelines, and in compliance with the OECD principles of Good Laboratory Practice. The test substance did not cause a reduction in the endogenous respiration at day 7. The test substance is therefore considered to be non-inhibitory to the inoculum. Test substance was biodegraded by 71% at day 28 in the OECD301 Closed Bottle test. The 14-day window that can be applied to closed bottle tests, where 60 % biodegradation must be achieved following the attainment of 10 % biodegradation, is not applied to multi-constituent or UVCB substances consisting of structurally similar constituents (OECD, 2006). The test is valid as shown by an endogenous respiration of 0.8 mg/L. Sodium acetate was degraded by 83% of its theoretical oxygen demand after 14 days. Finally, oxygen concentrations >0.5 mg/L in all bottles during the test period. Under the conditions of this study, this substance should be classified as readily biodegradable.