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No test data are available for Chlorodimethylsilane. Reliable short-term aquatic toxicity tests results are however available from two read-across substances (Dimethylsilanediol, 1066-42-8, and Trimethylsilanol, 1066-40-6). The hydrolysis half-life of Chlorodimethylsilane indicates that, under conditions relevant to short-term aquatic toxicity tests 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.

A 96-hour LC50 of 271 mg/L has been determined for the effects of Trimethylsilanol on mortality of Oncorhynchus mykiss. A NOEC of 128 mg/L has been determined in the same test. A 96-hour LC50 value of >126 mg/L and NOEC of ≥126 mg/L have been determined for the effects of Dimethylsilanediol, 1066-42-8, on mortality of O. mykiss.

A 48-hour EC50 of 124 mg/L has been determined for the effects of Trimethylsilanol on mobility of Daphnia magna. A NOEC of <60 mg/L has been determined in the same test. A 48-hour EC50 value of >117 mg/L and NOEC of ≥117 mg/L have been determined for the effects of Dimethylsilanediol on mobility of D. magna.

A 72-hour EC50 of >1053 mg/L and NOEC of 70 mg/L have been determined for the effects of Trimethylsilanol 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 Dimethylsilanediol on growth rate of P. subcapitata.

The results of the tests with Trimethylsilanol (CAS 1066-40-6) have been selected as the key results because they are definitive values.