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Long-term toxicity to aquatic invertebrates

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Description of key information

Long-term toxicity to invertebrates: 21-day NOEC ≥45 mg/l (Silanol HP1, read across from a structural analogue); >0.8 mg/l (Silanol HP2 and Silanol HP3, read across from a structural analogue).

Key value for chemical safety assessment

Additional information

Although not required to be included in the REACH data set at this annex level, consideration has been given to the potential long-term toxicity of the three silanol hydrolysis products of the major constituents, in the context of defining a predicted no-effect concentration. The conclusions are based on existing studies with analogous test materials under conditions in which test organisms were exposed predominantly to the same (or structurally similar) silanol molecules due to hydrolysis of the tested substances under the conditions of the test.

Silanol HP1: A 21-day NOEC of ≥100 mg/l (nominal) has been read-across from a structural analogue, trichloro(ethyl)silane (CAS 115-21-9), for effects on survival and reproduction of Daphnia magna. The study was conducted according to a standard guideline (OECD TG 211) and GLP. It is likely that the test organisms were exposed exclusively to the hydrolysis products of the substance, ethylsilanetriol (1 mole) and chloride (three moles). Chloride is not likely to have contributed to toxicity at the tested concentrations. The NOEC value expressed in terms of ethylsilanetriol is ≥45 mg/l.

Silanol HP2 and HP3: A 21-day NOEC of ≥1 ppm (≥1 mg/l) has been read-across from a structural analogue, N-(3-(trimethoxysilyl)propyl)ethylenediamine (CAS 1760-24-3) on survival and reproduction of Daphnia magna.The study was conducted according to a methodology similar to that recommended in the standard guidelines for this endpoint, although not in accordance with GLP. It is likely that the test organisms were exposed predominantly to the hydrolysis products of the substance, N-(3-(trihydroxysilyl)propyl)ethylenediamine (1 mole) and methanol (three moles). Methanol is not likely to have contributed to toxicity at the tested concentrations. The NOEC value expressed in terms of N-(3-(trihydroxysilyl)propyl)ethylenediamine is ≥0.8 mg/l.