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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

(7-d) EC50 210 mg/L, Pseudokirchnerella subcapitata, rel. 2 (read-across from CAS 2768-02-7)

Key value for chemical safety assessment

EC50/LC50 for freshwater algae:
210 mg/L
EC10, LC10 or NOEC for freshwater algae:
25 mg/L

Additional information

A 72-h EC50 value of 76 mg/l has been determined for the effects of the registered substance on growth rate of Scenedesmus subspicatus (new name: Desmodesmus subspicatus). A NOEC of 54 mg/l has been determined in the same test. However, the study has been disregarded because the test medium was not neutralised and one of the hydrolysis products, acetic acid, is produced in large quantities and does lower the test medium pH.

Data are however available for a structurally-related substance, trimethoxyvinylsilane (see Aquatic toxicity section for read-across justification). A 7-day EC50 value of 210 mg/l and NOEC of 25 mg/l have been reported for the effects of trimethoxyvinylsilane (2768-02-7) on final yield of Pseudokirchnerella subcapitata. It is likely that the test organisms were primarily exposed to the hydrolysis products of the substance.

A reliable QSAR is also available for the hydrolysis product, ethylsilanetriol, where a 96-h EC50 value of 1200 mg/l has been determined. This value supports the read-across and the decision to disregard the study available with the registered substance.