Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Biodegradation in water (screening test): ready biodegradability

The test was conducted under GLP according to OECD TG 301 C. Within 28 days, a degradation rate of 0 % was determined. Therefore, the test substance is 'Not Readily Biogradable'. The reference compound aniline shohed 74 % degradation after 14 days.

Biodegradation in water and sediment (simulation test)

ZMB2 dissociates to MB2 and zinc ions within seconds when a non-aqueous solution of ZMB2 is exposed to an aqueous environment.

Therefore, a read-across approach (structural analogue or surrogate) from Vulkanox ZMB2 (1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione, zinc salt; CAS 61617-00-3) to Vulkanox MB2 (1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2- thione, CAS 53988-10-6) was conducted for this endpoint.

This study is concerned with the aerobic mineralisation of ZMB2 in natural surface water under controlled laboratory conditions. It was carried out according to the OECD Guideline 309 "Aerobic Mineralisation in Surface Water – Simulation Biodegradation Test”. The incubation was performed using a 14C-labelled test item [phenyl-U-14C]zinc-4- and 5-methyl-2-mercaptobenzimidazole under aerobic conditions at 12 °C in the dark. The DegT50 value of MB2 (12° C) is 12.9 days (low concentration) and 24.6 days (high concentration).

Additional information