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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

No data are available for Chlorodimethylsilane. A 72-hour EC50 of >1053 mg/L and NOEC of 70 mg/L have however been determined for the effects of a read-across substance, Trimethylsilanol (CAS 1066-40-6), on growth rate of Selenastrum capricornutum (new name: Pseudokirchnerella subcapitata).  The corresponding results of the same test expressed relative to mean measured concentrations were >750 mg/L and 50 mg/L.A 72-hour EC50 value of >118 mg/L and NOEC of ≥118 mg/L have been determined for the effects of a second read-across substance, Dimethylsilanediol, 1066-42-8, on growth rate of P. subcapitata. The results of the test with Trimethylsilanol (CAS 1066-40-6) have been selected as the key results because they are definitive values.

Key value for chemical safety assessment

Additional information

No test data for toxicity to aquatic algae and cyanobacteria are available for Chlorodimethylsilane. However reliable data for toxicity to algae are available for the related substances Dimethylsilanediol, 1066-42-8, and Trimethylsilanol, 1066-40-6. The hydrolysis half-life of Chlorodimethylsilane indicates that, under conditions relevant to the algal test, hydrolysis to Dimethylsilanol and hydrogen chloride will occur. The properties of hydrogen chloride are well characterised and are discussed in the CSR. Its effects on aquatic organisms are limited to those that result from changes to pH in unbuffered media. Read-across from trimethylsilanol and dimethylsilanediol to dimethylsilanol is appropriate because all are small molecule alkylsilanols containing Me-Si and HO-Si groups; their properties are expected to be similar.