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EC number: 221-336-6
CAS number: 3069-29-2
(CAS 3069-29-2) will hydrolyse very rapidly (half-life 15 minutes at pH
7 and 25°C) in contact with water and atmospheric moisture to form
N-[3-(dihydroxymethylsilyl)propyl]ethylenediamine and methanol. Aquatic
organisms are therefore likely to be predominately exposed to
the hydrolysis products of the registered substance rather than the
REACH guidance (ECHA 2016,
R.16) states that “for substances where hydrolytic DT50 is
less than 12 hours, environmental effects are likely to be attributed to
the hydrolysis product rather than to the parent itself”. The substance
will be exposed to the environment through wastewater treatment plant
(WWTP) effluent only.
The minimum residency time
in the wastewater treatment plant is approximately 7 hours (although
this is a conservative figure and wastewater treatment time may be
hours longer) with an average temperature of 15°C (assumed to be at
neutral pH). Significant degradation by hydrolysis would be expected
before the substance is released to the receiving waters.
The environmental hazard
assessment, including sediment and soil compartments due to water and
moisture being present, is therefore based on the properties of the
silanol hydrolysis product, in accordance with REACH guidance.
The properties of methanol
have been discussed extensively in the public literature and it is not
hazardous at the concentrations at which it would have been present in
the toxicity tests reviewed in this assessment. The
short-term EC50and LC50values for this substance
are in excess of 1000 mg/l (OECD 2004a - SIDS for methanol). Therefore,
the environmental hazard assessments that follow (including those for
sediment and soil compartments) are based on the assumption that the
observed effects are the result of exposure to the silanol hydrolysis
product of the registered substance,
As described in Section 4.8
of IUCLID and Section 1.4 of the CSR, silanols may undergo condensation
reactions to give siloxane dimers, oligomers and polymers at high enough
concentrations. Condensation reactions become significant at
approximately 1000 mg/l. No observations on condensation were reported
in the read-across studies.
There are no reliable data
available for N-[3-(dimethoxymethylsilyl)propyl]ethylenediamine (CAS
3069-29-2) for ecotoxicity. In order to reduce testing, the Annex
requirements are fulfilled with data from substances that have similar
structures and physico-chemical properties.
Ecotoxicological studies are
conducted in aquatic media or in moist environments; therefore the
hydrolysis rate of the substance is particularly important since after
hydrolysis occurs the resulting product has different physicochemical
properties and structure.
The registered substance
hydrolyses very rapidly in water and therefore the selection of the
read-across substance is based on the silanol hydrolysis products, the
groups present on the side chains, as well as the log Kow since
this contributes to bioavailability.
The analogue approach for
fulfilling the data requirement by read-across is discussed according to
the Read-across Assessment Framework (RAAF).
Data have been read-across
from N-(3-(trimethoxysilyl)propyl)ethylenediamine (CAS 1760-24-3). In
the context of the RAAF, the basis of the read-across hypothesis for
this substance is “Different compounds have the same type of effect(s)”;
Scenario 2 applies. Both the source and target substance hydrolyse to
compounds with qualitatively similar properties.
Please see the report
attached in Section 13 for the analogue approach to address ecotoxicity
of N-[3-(dimethoxymethylsilyl)propyl]ethylenediamine (CAS 3069-29-2) by
read-across from N-(3-(trimethoxysilyl)propyl)ethylenediamine (CAS
Conclusions on classification have
been made for the parent substance,
N-[3-(Dimethoxymethylsilyl)propyl]ethylenediamine (CAS 3069-29-2).
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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