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EC number: 221-066-9
CAS number: 2996-92-1
The simulation test on ultimate degradation in surface water/sediment
and identification of degradation products do not need to be conducted
- in accordance with Column 2 of REACH Annex IX, the chemical safety
assessment according to Annex I indicates that this is not necessary,
- in accordance with Section 3 of REACH Annex XI, exposure of the
aquatic/sediment compartment is not significant.
The simulation test on ultimate degradation in surface water and
sediment as well as the identification of degradation products do not
need to be conducted as:
Many organosilicon compounds hydrolyse rapidly to a silanol and a
by-product such as ethanol, methanol or HCl. For most organosilicon
compounds, little or no degradation is observed in ready biodegradation
studies once degradation of any readily biodegradable hydrolysis
by-product is accounted for. This is supported by a small number of
simulation studies that show limited biodegradation. Therefore, most
organosilicon compounds either meet the criteria for persistence or
produce transformation products that may meet the criteria for
persistence based on currently available data.
The registered substance is ‘not readily biodegradable’ based on
read-across from a structural analogue. The registration substance
hydrolyses (DT50 = 0.4 h) to phenylsilanetriol and methanol. The
exposure assessment and risk characterisation is carried out for the
silanol hydrolysis product of the substance on the basis that it is not
biodegradable. Risk characterisation ratios are below 1. The non-silanol
hydrolysis product, methanol, is readily biodegradable. Therefore,
further testing for biodegradation would not affect the outcome of the
environmental risk characterisation.
Since degradation of the registration
substance is expected to be principally via abiotic transformation under
the aqueous conditions of a degradation simulation study, the
transformation products expected in the environment are those identified
as the hydrolysis products in Section 5.1.2 of the IUCLID.
The silanol hydrolysis product of the registered substance is considered
to be not B based on its low log Kow of -0.021. Therefore, further
testing for persistence would not affect the overall outcome of the
The chemical safety assessment does not indicate any need to investigate
further the degradation of the substance, or either of its hydrolysis
products, at the present time.
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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