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Ecotoxicological information

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Additional information

Diethoxy(dimethyl)silane (CAS 78-62-6) is neither toxic nor hazardous to aquatic organisms.


Diethoxy(dimethyl)silane (CAS 78-62-6) hydrolyses rapidly in contact with water (estimated DT50: 5.5 h), to dimethylsilanediol (CAS 1066-42-8) and ethanol. REACH guidance R.16 states that “for substances where hydrolytic DT50 is less than 12 h, environmental effects are likely to be attributed to the hydrolysis product rather than to the parent itself” (ECHA, 2016). TGD (EC, 2003) and REACh guidance R.16 (ECHA, 2016) also suggest that when the hydrolysis half-life is less than 12 h, the breakdown products, rather than the parent substance, should be evaluated for aquatic toxicity testing. Additional information is given in a supporting report attached in IUCLID Section 13 (PFA, 2016).

Acute toxicity studies evaluating the short-term toxicity of the silanol hydrolysis product dimethylsilanediol (CAS 1066-42-8) to aquatic organisms are available for all three trophic levels. All studies were performed according to international guidelines and GLP standards. No short-term toxic effects were observed towards the tested organisms of all three trophic levels up to the highest tested concentration. 

In order to assess the toxicity of Diethoxy(dimethyl)silane (CAS 78-62-6) to microorganisms data were read-across from Trimethoxy(methyl)silane (CAS 1185-55-3). The EC10 (3 h) was found to be > 100 mg/L. On this basis, no toxic effects are anticipated by the target substance to activated sludge microorganisms.