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Ecotoxicological information

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Measured data were available for trimethoxy(propyl)silane for aquatic toxicity for each of the three trophic levels.

The reported effect concentrations were an EC50of > 913 mg/l for the effect on growth rate on the algae Scenedesmus subspicatus (new name: Desmodesmus subspicatus) (EU Method C.3 (Algal Inhibition test), for fish a 96 hour LC50 of > 746 mg/l (EU Method C.1 (Acute Toxicity for Fish) and for Daphnia magna an 48 hour EC50 of > 816 mg/l (EU Method C.2 (Acute Toxicity for Daphnia). No toxicity of trimethoxy(propyl)silane could be determined.

As the substance hydrolyses rapidly (half-life approximately 2.6 hours at pH 7, 20-25°C) to propylsilanetriol, under ecotoxicity testing conditions the organisms will therefore be exposed predominantly to the hydrolysis product. The other hydrolysis product is methanol and the properties of this substance are well-characterised.

Methanol is non-toxic to the environment at the concentrations relevant to this assessment and it is considered unlikely that it’s presence significantly affected the results of the test performed with trimethoxy(propyl)silane.