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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

After 28 days the biodegradation of the registered substance was recorded as 76.84% (based on CO2 evolution) and 72.03% (based on DOC). The substance is readily biodegradable but not meeting the 10 day window criteria.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable but failing 10-day window

Additional information

The biodegradation potential of the registered substance was determined in accordance with the OECD Guideline for Testing of Chemicals 301B. The test substance was tested for ready biodegradability using activated sludge of a sewage treatment plant receiving predominantly domestic sewage. The test was conducted over a period of 28 days. After 28 days the biodegradation of the test substance was recorded as 76.84% (based on CO2 evolution) and 72.03% (based on DOC). Based on measuring the test substance concentration by HPLC, the test substance was < 0.1 mg/L at the 14th day of the test. Therefore the test substance is considered to readily biodegradable without meeting the 10 day window criteria. An additional study was conducted on a formulated product containing the registered substance to determine the inherent biodegradability of the formulated product. The inherent biodegradability of the test material was determined in accordance with the OECD Guideline for Testing of Chemicals 302B. The biodegradation of the substance was measured by COD analysis. 0.1825 ml/l (equivalent to 142.9 mg/l COD) of test substance was added to test vessels containing 357.1 mg/l of activated sludge. The final 56 day degradation value was determined to be 78.6% at 0.1825 ml/l of test substance. From the results of this study it can be concluded that p-TSA Triethanolamine salt does not meet the criteria for classification as 'inherently biodegradable' according to the OECD 302B method, with >70% biodegradation being achieved within the 56 day test period. The test material shows good potential for ultimate biodegradation under the conditions of this study.