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EC number: 252-161-3
CAS number: 34708-08-2
No terrestrial toxicity data are
available for the registered substance.
has a half-life of 23 hours at pH 7 and 25 °C, which indicates that the
substance will be completely hydrolysed to
triethoxy(3-thiocyanatopropyl)silanetriol and ethanol by the time the
substance reaches the terrestrial compartment. Therefore, the
terrestrial assessment is based on the hydrolysis products.
Consideration of the Si
hydrolysis product: triethoxy(3-thiocyanatopropyl)silanetriol
In the context of the Integrated
Testing Strategy for the terrestrial compartment (ECHA guidance Chapter
R.7c, terrestrial hazard classification scheme, Table R.7.11—2) (ECHA
2017) the aquatic toxicity tests do not indicate that the substance is
very toxic (EC/LC50 >1 mg/L for algae, Daphnia and
fish). However, despite degradation of the parent substance, the silanol
hydrolysis product may persist in the environment. The substance is
therefore assigned to Hazard Category 3.
this situation, a screening approach is applied, where the equilibrium
partitioning risk assessment approach is applied with an extra factor of
ten and, in addition, a confirmatory long-term terrestrial test is to be
The PEC × 10 / PNECscreen based on
the equilibrium partitioning method (EPM) indicates the substance will
have a risk characterisation ratio (RCR) >1. The highest terrestrial RCR
is 8.48 in agricultural soil.
Confirmatory long-term test:
An OECD 222 study with earthworms
is proposed with the registered substance.
In addition, ECHA guidance Chapter
R.7c, Table R.7.11—2 states the following: "If PEC/PNECscreen > 1 or
indication of risk from confirmatory long-term soil toxicity test:
Conduct long-term toxicity tests according to the standard information
requirements Annex IX or X (invertebrates and plants), choose lowest
value for derivation of PNECsoil". The PEC/PNECscreen is >1, which
indicates that standard information requirements according to Annex IX
or X should be conducted. However, a long-term aquatic toxicity study
with invertebrates, OECD 211, is proposed, which is likely to affect the
PEC/PNECscreen. Therefore, it is proposed to review the results of the
screening assessment once the OECD 211 and 222 study results are
available, before concluding on the need to conduct an OECD 208
long-term toxicity to terrestrial plants study.
Furthermore, toxicity was observed
in the aquatic microorganism test (3 hour EC50 130 mg/L; EC10
4.3 mg/L (activated sludge respiration inhibition)). ECHA
guidance Chapter R.7c states “Where inhibition of sewage sludge
microbial activity has been observed in Annex VIII testing, a test on
soil microbial activity will additionally be necessary for a valid PNEC
to be derived.” A soil microorganisms nitrogen inhibition test (OECD
216) is therefore also proposed.
the meantime, a PNEC and the risk characterisation ratio have been
derived based on EPM, details of which can be found in IUCLID Section
6.0 and Chapters 9 and 10 of the Chemical Safety Report, respectively.
Consideration of the non-Si
hydrolysis product: ethanol
Due to the volatile nature of
ethanol, it is considered unlikely that it would reach the terrestrial
compartment. In addition, ethanol is considered to be of low toxicity to
terrestrial organisms in the public domain literature and is not
hazardous at the concentrations relevant to the studies relevant to
Annex IX requirements. Some studies also indicate potentially
stimulating effects to plants - although the significance of the studies
is doubtful (OECD 2004 SIDS for ethanol, CAS 64-17-5).
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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