[3-(2,3-epoxypropoxy)propyl]triethoxysilane

Short-term toxicity to aquatic invertebrates

Description of key information

(48-h) EC50: >100 mg/l, nominal, Daphnia magna, reliability 1.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

mg/L

Additional information

A 48-hour EC₅₀ value of >59 mg/l and a NOEC of ≥59 mg/l have been determined for the effects of the registered substance on mobility of Daphnia magna based on geometric mean measured exposure concentrations. The corresponding nominal exposure concentration was 100 mg/l. It is likely that the test organisms were exposed to a mixture of parent substance and hydrolysis products. The results are assessed on the basis of nominal concentrations because it is not possible to establish the identity of the substance(s) that the analysis relates to (see section 7.1.1).

The results of a supporting study with the registered substance are also available. A 48-h EL₅₀ value of ≥100 mg/l has been determined for the effects of the substance on mobility of Daphnia magna based on nominal test substance loading rate. A corresponding 48-h EC₅₀ of ≥40 mg/l has been determined by the reviewer based on measured DOC concentration. A reliable NOELR/NOEC cannot be determined from the test results because corresponding test media were prepared by dilution of a filtered stock dispersion. The results of a second test conducted as part of this study have been discounted because the test media preparation regime included a stirring period of 48 hours and the pH of the test medium was relatively high (7.7. to 8.4). At this pH it is estimated that the substance will hydrolyse 5 to 10 times faster than the measured hydrolysis half-life: 12 – 36 h at pH 7 and 25°C (OECD 111). Therefore the test organisms were predominantly exposed to the hydrolysis product of the substance.