Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

A reliable study on the ready biodegradability of the submission item (a modified MITI test in accordance with OECD TG 301-C, Iizuka 2002) showed that no biodegradation of the substance was observed over the test period of 28 days. Considering the lack of biodegradation observed in the ready biodegradation test, it is to be expected that the submission item is unlikely to be degraded to a significant extent under the conditions of an inherent biodegradability study, unless a toxic effect to the microorganism community was the reason for the absence of degradation. In the study of Clarke (2002) on the toxicity to microorganisms according to OECD TG 209 the NOEC was found to be 10 times lower than the initial concentration in the ready biodegradation test of 100 mg/L. The EC 50 in this study was at 70 % of the concentration used in the MITI test for ready biodegradability. It seems therefore possible, that significant intoxication of the microorganism community prevented biodegradation the MITI test.

Nonetheless, as long as no data are becoming available indication ultimate biodegradability of the substance under real environmental conditions, the test item should be regarded as non-biodegradable.