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Environmental fate & pathways

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Biodegradation in water: biodegradable

Additional information

Significant (65%) degradation was observed in a Closed Bottle test utilising a test concentration of 2 mg/L. A modified MITI test using a high test concentration of 100 mg/L resulted in low biodegradability.

The higher degree of biodegradation observed in tests with a lower initial test substance concentration indicates limited bioavailability. It is possible that the rate of biodegradation may be limited by the rate of hydrolysis of the test substance and/or the rate with which the substance dissolves. Modelling of possible biodegradation pathways indicate that aerobic degradation is likely, the first steps in this being hydrolysis to trimellitic acid and octanol, both of which have been shown to be readily biodegradable.

Tests with a structural analogue of the substance, a trimellitate ester with mixed C8 -C10 side chains, showed significant biodegradation and, while not readily biodegradable, this analogue can be considered to be inherently biodegradable. The differences observed in tests on the two substances may be a result of methodology, particularly important when testing “difficult” substances – in this case, substances with low water solubility.

 

There are no data for sediment or soil biodegradation studies relating to the substance. Such studies are not needed due to the fact that the substance can be regarded as being readily biodegradable.