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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The test item is considered not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

The test item BAL0001026 was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days. The biodegradation was evaluated based on the oxygen uptake of the microorganisms during exposure. As a reference item Sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

The test system was a microbial inoculum collected from a sewage plant processing domestic sewage. The sludge was allowed to settle and then aerated until being used.

Under the test conditions the percentage biodegradation of BAL0001026 reached a mean of 7.4 % after 28 days based on the theoretical oxygen demand (ThOD) of active substance of the test item. According to the test guidelines the pass level for ready biodegradability is removal of 60 % ThOD. Therefore the test item is considered not readily biodegradable. 

The toxicity of BAL0001026 on secondary microorganisms in the effluent was also investigated. In the toxicity control containing both, the test item and the reference item Sodium benzoate, a mean of 35.9 % biodegradation was noted within 14 days and 39.5 % biodegradation after 28 days of incubation.

According to the test guidelines the test item can be assumed to be not inhibitory at the applied concentration level of 2.5 mg active substance/L (equivalent to 2.9 mg test item /L) on the secondary effluent microorganisms because degradation was >25 % within 14 days.


The test item was not considered to have significant inhibitory effects on the secondary effluent microorganisms.

Based on the results of this study, the test item is considered not readily biodegradable.

[Type of water: freshwater]