Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Short-term toxicity to invertebrates: 48-hour EC50 >500 mg/L (Silanol HP1, read across from a structural analogue); 331 mg/L (Silanol HP2, read across from a structural analogue); >151 mg/L (Silanol HP3, read across from a structural analogue).      

The four major constituents of the registered substance undergo hydrolysis in water, with a half-life <12 h at pH7 and 25°C in all cases. Therefore to support the chemical safety assessment of the hydrolysis products, short-term toxicity tests for fish have been read-across from structural analoguous substances which degrade to produce the same or similar silanols in solution.

Key value for chemical safety assessment

Additional information

The REACH data requirements are fulfilled by consideration of the three silanol hydrolysis products of the major constituents, which are based on 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 48-hour EC50 value of >500 mg/l and NOEC of ≥500 mg/l (nominal) have been read-across from a structural analogue, triethoxy(methyl)silane, CAS 2031-67-6, for effects on mobility of Daphnia magna. The study was conducted according to a standard guideline (EU Method C.2) and GLP. It is likely that the test organisms were exposed predominantly to the hydrolysis products of the substance, methylsilanetriol (1 mole) and ethanol (three moles). Ethanol is not likely to have contributed to toxicity at the tested concentrations. The EC50 value expressed in terms of methylsilanetriol is >500 x (94.14/178.31) = >264 mg/l.

Silanol HP2: A 48-hour EC50 value of 331 mg/L and NOEC of 94 mg/L have been read across from a structural analogue, 3-aminopropyltriethoxysilane (CAS 919-30-2), for effects of the test substance on mobility of the freshwater invertebrate Daphnia magna. The study was conducted according to a standard guideline (OECD TG 202) and GLP. It is likely that the test organisms were exposed predominantly to the hydrolysis products of the substance, 3-aminopropylsilanetriol (1 mole) and ethanol (three moles). Ethanol is not likely to have contributed to toxicity at the tested concentrations. The EC50 value expressed in terms of 3-aminopropylsilanetriol is >331 x (137.21/221.37) = 205 mg/l.

Silanol HP3: A 48-hour LC50 value of >200 mg/L (nominal), >151 mg/l (measured, initial) have been read across from a structural analogue,  bis(triethoxysilylpropyl)amine (CAS 13497-18-2) for effects on mortality of Acartia tonsa. The study was conducted according using a standard method (ISO standard 14669, similar to OECD TG 202) and  It is likely that the test organisms were exposed predominantly to the hydrolysis products of the substance, bis(trihydroxysilylpropyl)amine (1 mole) and ethanol (six moles). Ethanol is not likely to have contributed to toxicity at the tested concentrations. The EC50 value expressed in terms of bis(trihydroxysilylpropyl)amine is >151 x (257.39/425.72) = >91 mg/l.

A 48-hour EC50 value of >100 mg/l (nominal) has been read across from a structural analogue bis(trimethoxysilylpropyl)amine (CAS 82985-35-1), for effects on mobility of Daphnia magna under conditions where pH is controlled. The EC50 was also >100 mg/l (nominal) under conditions where pH variation in the test media was not corrected. It is likely that the test organisms were exposed predominantly to the hydrolysis products of the substance, bis(trihydroxysilylpropyl)amine (1 mole) and methanol (six moles). Methanol is not likely to have contributed to toxicity at the tested concentrations. The EC50 value expressed in terms of bis(trihydroxysilylpropyl)amine is >100 x (257.39/341.56) = >75.3 mg/l.