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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

The substance rapidly degrades to the free acid in aerobic sediment/water systems at 20 °C. This metabolite was also readily degraded under non-sterile conditions to carbon dioxide. Because of the significant dissipation of the substance from the water and sediment phases and the subsequent mineralization to CO2 the test substance and is principal degradation products should not accumulate in surface waters and sediments under normal environmental conditions.

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Additional information

Two studies investigating the biodegradation in water sediment systems under aerobic and anaerobic conditions were performed according to US-EPA 162-4 and 162-3, respectively, as well as GLP conditions. One label was used to investigate the aerobic degradation rate and the pathway. The radioactively labelled substances were applied to the water body at a target rate of 61.1 and 61.3 μg test item per test vessel for the aerobic and anaerobic treatment, respectively.

This study demonstrated that the substance disappeared fast from the entire system with DT50 values of 0.19 days and 1.5 days under aerobic conditions for two different systems, Hoechst sediment and North Carolina system sediments, respectively, as well as 0.5 days under anaerobic conditions in North Carolina system sediment.

Overall, three transformation products were detected, and in the aerobic treatment, carbon dioxide formation was considerable, while remaining low in the anaerobic treatment, indicating the complete mineralization of the test item. The test item is relatively weakly absorbed to soil, but the overall degradation is fast. Formation of carbon dioxide and metabolites demonstrates the complete degradation of the substance in water-sediment systems.