3-chloropropyltrimethoxysilane

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish early-life stage toxicity

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Description of key information

Endpoint waived

Additional information

Testing for long-term toxicity to fish is not considered necessary because:

 

No data are available for the registered substance, which rapidly hydrolyses to (3-chloropropyl)silanetriol and methanol.

The Chemical safety assessment and PNECs are based on these hydrolysis products, of which methanol is not expected to result in any effects at concentration levels relevant to a study. The data waiver is applicable to the silanol hydrolysis product.

 

In accordance with Column 2 of REACH Annex IX, there is no need to further investigate the effects of this substance in a long-term aquatic toxicity to fish study because, as indicated in guidance R.7.8.4.3 (ECHA 2017), the quantitative chemical safety assessment (conducted according to Annex I of REACH) indicates that the Risk Characterisation Ratio is below 1 and therefore the risk is already adequately controlled and further testing is not justifiable.

 

The substance is highly water-soluble, has low potential for bioaccumulation (based on log K_ow <3 (-1.1)) and there is no reason to expect any specific mechanism of toxicity beyond narcosis. Therefore, the occurrence of toxic effects that were not expressed in the existing short-term aquatic studies (the lowest measured EC₅₀ was 869 mg/l, equivalent to 685 mg/l in terms of the silanol hydrolysis product, reported for effects with Daphnia) would be considered unlikely.

 

Long term toxicity to aquatic invertebrates data have been read across from a structural analogue. No effects were reported. There is no reason to suspect that fish would be any more sensitive that invertebrates, therefore long-term toxicity to fish is not expected either.

 

Long-term toxicity was observed above 100 mg/l in the algal test. A PNEC using the algal NOEC has been derived for the purpose of chemical safety assessment. An assessment factor of 50 was applied to derive the freshwater PNEC, this high assessment factor to derive the predicted no-effect level already reflects the fact that two, rather than three, long-term tests are available. For a narcotic chemical without a specific mode of toxic action, it is unlikely that the aquatic PNEC would be significantly over-estimated using this method.

 

Overall it is concluded that the risk characterisation conclusion is sufficiently conservative in respect of any uncertainties and therefore further in vivo testing is not considered necessary or justified on ethical grounds.

Details on how the PNEC and the risk characterisation ratio have been derived can be found in IUCLID Section 6.0 and Chapters 7, 9 and 10 of the Chemical Safety Report.