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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

A 48-hour EC50 of >100 mg/L has been determined for the effects of a read-across substance (Dimethoxydimethylsilane; CAS No. 1112-39-6) on mobility of Daphnia magna. This study has the lowest EC50 of the constituents that have been tested. This study is considered reliable without restrictions and, therefore, may be used to conclude that dimethylsilanediol and dichloro(dimethyl)silane are not acutely toxic to aquatic invertebrates. It is used to read across to all constituents of MS-Silane.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
100 mg/L

Additional information

No data for short-term toxicity to invertebrates are available for MS-Silane. However studies of short-term toxicity to invertebrates are available for dimethoxy(dimethyl) silane and dimethylsilanediol. Both dimethoxy(dimethyl) silane (CAS No. 1112-39-6) and Dichloro(dimethyl) silane (CAS No. 75-78-5) hydrolyse to dimethylsilanediol (CAS No. 1066-42-8). Data are also available for hexamethyldisilane (CAS 1450-14-2), trimethylsilanol (CAS 1066 -40 -6) and tetraethylorthosilicate (CAS 78 -10 -4). The hydrolysis half-lives of the methoxysilanes and chlorosilanes indicate that, under conditions relevant to ecotoxicity assessment, both will hydrolyse rapidly. The other hydrolysis products are methanol and hydrogen chloride, respectively; the properties of these substances are well characterized. Methanol is non-toxic to the environment and it is considered unlikely that it’s presence significantly affected the results of the test performed with dimethoxy(dimethyl) silane. Effects of hydrogen chloride on aquatic organisms are limited to those that result from changes to pH in un-buffered media and are discussed in the CSR.

The following information is taken into account for short-term toxicity to aquatic invertebrates for the derivation of PNEC:

A 48-hour EC50 of >100 mg/L has been determined for the effects of a read-across substance (Dimethoxydimethylsilane; CAS No. 1112-39-6) on mobility of Daphnia magna. This study has the lowest EC50 of the constituents that have been tested. This study is considered reliable without restrictions and, therefore, may be used to conclude that dimethylsilanediol and dichloro(dimethyl)silane are not acutely toxic to aquatic invertebrates. It is used to read across to all constituents of MS-Silane.