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EC number: 812-491-6
CAS number: 1312943-23-9
Toxicity to aquatic algae has been assessed in two reliable studies
conducted with substances that would fall within the MDI category
definition. The studies used water accommodated fractions or saturated
solutions as the test items are poorly soluble. Both studies
demonstrated EC50 values above the highest concentration tested, and
NOEC values at the highest test concentration.
Based on these results, members of the MDI category are not expected to
be toxic to aquatic algae at the limit of solubility.
studies were conducted on three different MDI category members in order
to assess toxicity to aquatic algae. Two of the studies are considered
to be reliable and one is unreliable, and has therefore been disregarded
from the assessment.
study was performed to assess the effects of Reaction product of
4,4’-methylenediphenyl diisocyanate and amines, coco alkyl on the growth
of the green alga Pseudokirchneriella subcapitata (Vryenhoef 2018). The
method followed was designed to be compatible with the OECD guideline
201, “Freshwater Alga and Cyanobacteria, Growth Inhibition Test”.
Following a preliminary range-finding test, Pseudokirchneriella
subcapitata was exposed to Water Accommodated Fractions (WAF) at a
single nominal loading rate of 100 mg/L (six replicate flasks) for 96
hours, under constant illumination and shaking at a temperature of 24 ±
1°C. Samples of the algal populations were removed daily and cell
concentrations determined for each control and treatment group, using a
Coulter® Multisizer Particle Counter.
values for growth rate and yield were determined to be greater than 100
mg/L WAF. Correspondingly the No Observed Effect Loading Rate was 100
mg/L WAF. It was considered unnecessary and unrealistic to test at
loading rates in excess of 100 mg/L. LC-MS/MS analysis of the test
preparations was performed at 0 and 96 hours and measured concentrations
of less than the limit of quantification (0.00046 mg/L) were obtained.
Given that the toxicity cannot be attributed to a single component or a
mixture of components but to the test item as a whole the results were
based on nominal loading rates only.
second study was performed to assess the effect of
3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea (EC 406-370-3)
on the growth of the green alga Desmodesmus subspicatus. The method
followed was designed to be compatible with the EC Method C3 and a
nominal loading rate of 1 mg/L was used. The study determined EC50 and
NOEC values for growth rate and biomass of greater than 1 mg/L, the
limit of water solubility.
study conducted with N,N''-(methylenedi-4,1-phenylene)bis[N'-octyl]urea
(EC 445-760-8) did show effects below the highest concentration tested.
This study was included in a NONS registration and permission to refer
has been granted by ECHA under an Article 25(3) request. A limited
summary was provided in the data received from ECHA. Reference to the
same study on the ECHA dissemination portal indicates that the study has
subsequently been disregarded by the registrants as the study used very
high nominal loading rates (up to 4000 mg/L) and only analysed for one
constituent of the substance, which was found to be in solution at <LOQ
(0.5 mg/L). As the analysed constituent was present at <LOQ but a
dose-response relationship was observed at the highest loading rates,
toxicity appears to be attributed to an unknown impurity in the test
item. As it is not possible to determine which constituent the observed
toxicity is attributed to, the water solubility of the main constituent
should not be used for the reporting of results, as this is not the
constituent that is leading to the observed toxicity. This study has
therefore been disregarded as the results are unreliable.
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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