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EC number: 205-746-2
CAS number: 149-74-6
The hydrolysis half-life of the registration substance is approximately
very rapid therefore the hazard assessment for the terrestrial
compartments is based on the silanol hydrolysis product.
In accordance with Column 2 of REACH Annex IX, there is no need to
further investigate the effects of this substance in a long-term aquatic
toxicity to fish study because, as indicated in guidance R.188.8.131.52 (ECHA
2016), the quantitative chemical safety assessment (conducted according
to Annex I of REACH) indicates that the Risk Characterisation Ratio is
well below 1, even with due consideration of contributing uncertainties,
and therefore the risk is already adequately controlled and further
testing is not justifiable.
The substance is highly water-soluble, has low bioavailability
(based on log Kow <3 (0.8)) and there is no reason to expect
any specific mechanism of toxicity beyond narcosis. Therefore, the
occurrence of toxic effects that were not expressed in the existing
short-term aquatic studies (conducted at concentrations up to 1000 mg/l)
would be considered unlikely.
A PNEC has been derived for the purpose of chemical safety
assessment. An assessment factor of 1000 was applied to derive the
freshwater PNEC, this high assessment factor to derive the predicted
no-effect level already reflects the typically higher value of a
short-term EC50compared to a long-term EC10. For a
narcotic chemical without a specific mode of toxic action, it is
unlikely that the aquatic PNEC would be significantly over-estimated
using this method.
Overall it is concluded that the risk characterisation conclusion
is sufficiently conservative in respect of any uncertainties and
therefore further in vivo testing is not considered necessary or
justified on ethical grounds.
Details on how the PNEC and the risk characterisation ratio have
been derived can be found in IUCLID Section 6.0 and Chapters 9 and 10 of
the Chemical Safety Report, respectively.
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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