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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

closed bottle test:
In a read across study the analogue substance 9-Octadecenoic Acid was readily biodegradable in a closed bottle test.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Biodegradation in water

No adequate studies investigating the biodegradability of the test substance in water were identified. However, data from a structural analogue (read across substance) are available.

A closed bottle test was conducted according to OECD guideline 301D to assess the biodegradation rate of the analogue substance 9-Octadecenoic Acid within 28 days. Sodium benzoate was used as reference substance. Activated sludge from a domestic treatment plant was used as inoculum. The analogue substance was tested in two concentrations (2 and 5 mg/L) in two replicates each. As the oxygen content in the high concentration flasks was not as high as demanded for biodegradation, only the result of the 2 mg/L test substance concentrations were analyzed. The biodegradation rate (given as BOD /COD *100) was calculated to be 76 % after 7 days and 92 % within 28 days for the analogue substance, which therefore is concluded to be readily biodegradable. Another study revealed a BOD5 rate of 48 % (Canton J.H., W. Slooff, (1982). Substitutes for Phosphate Containing Washing Products: Their Toxicity and Biodegradability in the Aquatic Environment. Chemosphere 11:891ff).