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To assess the acute toxicity of N-(Morpholinomethyl)triethoxysilane to fish a limit test according to OECD 203 (EU Guideline 92/92/EEC C.1) was performed. In the control and the only test concentration (95.7 mg/L mean measured conc.) no mortality and no treatment related toxic effects were observed. Since at a mean concentration of 95.7 mg/L no effect on the test organisms was observed, it can be assumed that the LC 50 is also higher than 100 mg/L. Based on this N-(Morpholinomethyl)triethoxysilane is not considerd to be toxic to fish.

To assess the acute toxicity of N-(Morpholinomethyl)triethoxysilane to aquatic invertebrates (Daphnia magna) a test according to OECD 202 (EU Guideline 92/92/EEC C.2) was performed. In the control and the concentrations 69, 83, 100 and 120 mg/L (nominal) no immobile daphnias were observed. At the test concentration of 144 mg/L one daphnia was immobile, which was not assessed as significant by statistical evaluation. The measured concentrations were at least 93% of the nominal. Based on this N-(Morpholinomethyl)triethoxysilane is not considerd to be toxic to Daphnia magna.

The infuence of N-(Morpholinomethyl)triethoxysilane on the growth of the freshwater green algal species Desmodesmus subspicatus was assessed in a static dose-response test (OECD Guideline 201). The 72-hours IC50 value was calculated to be 25.0 mg/L (NOEC: 0.8 mg/L) for the growth rate, and 7.0 mg/L (NOEC: 0.8 mg/L) for the biomass. Thus, it can be concluded that N-(Morpholinomethyl)-triethoxysilane is harmful to the green algal species Desmodesmus subspicatus.

The influence of (N-Morpolinomethyl)triethoxysilane on the activity of activated sludge was evaluated by measuring the respiratory rate under defined conditions (OECD Guideline 209). The respiration rate (oxygen consumption) of an aerobic activated sludge fed with a standard amount of synthetic sewage was measure in the presence of various concentrations of the test item after an incubation period of 3 hours. Based on measured inibition rates, the 3 -hour EC20 and EC50 could not be quantified because up to the highest nominal test concentration of 1000 mg/L less than 20% inhibition was noted after three hours incubation. Nevertheless the 3 -hour EC20 and EC50 are clearly higher than 1000 mg/L under the reported conditions.The positve and the inocculum control worked as expected.