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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Short-term toxicity to fish: 96-hr LC50 439 mg/l (nominal) (EG Guideline 92/69 EWG Part C1). The LC50 is equivalent to 345 mg/l when expressed in terms of the silanol hydrolysis product.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
345 mg/L

Additional information

A 96-h LC50 value of 439 mg/l and NOEC of 350 mg/l (nominal) have been determined for the effects of the registration substance on mortality of Brachydanio rerio (new name: Danio rerio). In view of the test media preparation method and exposure regime it is likely that the test organisms were exposed predominantly to the hydrolysis products of the tested substance. At the loading concentration used in preparation of stock, it is expected that oligomers and/or cross-linked aggregates may have been present to some extent, though no specific evidence of precipitation or physical effects on test animals is described. While this is an uncertainty, it is considered that the study results are suitable to be used (with caution), with effects attributed in principle to intrinsic ecotoxicity of silanol (and oligomers).

The results may be expressed in terms of concentration of the hydrolysis product, 3-(trihydroxysilyl)propanethiol, by applying a molecular weight correction: (MW of silanol=154.26 / MW of parent=196.34) * 439 = 345 mg/l.

The reliability of three other LC50 values in the range 2.4 to 253 mg/L, that were obtained from the open literature, could not be determined.

Refer to the discussion in the Section 6 endpoint summary (Section 7.0 of CSR) for further discussion of the approach to chemical safety assessment for this registration substance.