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EC number: 258-904-8
CAS number: 53988-10-6
No abiotic degradation of the test item was observed. 1,3-Dihydro-4(or
5)-methyl-2H-benzimidazole-2-thione is found to be stable at 50°C at all
three pH-values. Therefore it can be assumed that the test item is also
stable at 25 °C and no half-life times and hydrolysis rates were
Biodegradation in water (screening test): ready biodegradability:
The ready biodegradability of the substance was determined according to
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)).
Within 28 days, a degradation rate of 0 % was determined. Based on this
result, the substance is regarded as not ready biodegradable.
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).
In accordance with Section 1 of REACh annex XI, a bioaccumulation study
is scientifically unjustified. The substance can be expected to have a
low pontential for bioaccumulation, because the substance has a low
octanol water partition coefficient (LogPow = 0.3-0.4).
The adsorption coefficient of 1,3-dihydro-4(or
5)-methyl-2H-benzimidazole-2-thione was tested according to OECD
Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil
and on Sewage Sludge using High Performance Liquid Chromatography
(HPLC)). The adsorption coefficient of the test item is deteminined to
be: log Koc = 1.9 or Koc = 79 L/kg.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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