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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The test substance is not readily or inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Two biodegradability tests are available for this substance, one investigating ready biodegradability according to OECD 301F and one inherent biodegradability according to OECD302C. The results are summarized as below:

The ready biodegradability test was performed over 28 days according to EU Commission Directive 92/69/EEC, C.4 -D (1992) and OECD Guideline for Testing of Chemicals No. 301 F (1992). There was no inhibitory effect on the activity of activated sludge microorganisms from the result of toxicity control. The biochemical oxygen demand (BOD) of the test item in the test media was in the range of the inoculum controls throughout the entire 28-day exposure period. Consequently, test item is not ready biodegradable under the valid test conditions within 28 days.

Additionally , the test item was investigated for its inherent biodegradability in a manometric respirometry test over 28 days based on the OECD Guideline for Testing of Chemicals No. 302 C (1981). The test temperature was 22 °C, maintained with a built-in thermostat and checked once per week, and pH was determined prior to test start and at the end of the test in each flask. The result of abiotic control showed that no significant degradation of test item occurred under the test conditions within 28 days. There was no inhibitory effect on the activity of activated sludge microorganisms from the result of toxicity control. The biochemical oxygen demand (BOD) of the test item in the test media was in the range of the inoculum controls in one of the two replicates and slightly above the range of the inoculum controls in the other replicate throughout the entire 28-day exposure period. At the end of the 28-day test period, the mean biodegradation of test item amounted to 13 % without nitrification and 8 % with nitrification. The biodegradation of reference substance was 78 % on day 14 and reached 86 % on day 28. Consequently, test item is not inherently biodegradable under the valid test conditions within 28 days.