3-(trimethoxysilyl)propiononitrile

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:

Additional information

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

The substance hydrolyses rapidly therefore the chemical safety assessment is based on the silicon containing hydrolysis product 3-(trihydroxysilyl)propiononitrile.

 

According to Regulation (EC) No. 1907/2006, Annex IX, Column 2, long term testing shall be proposed if the chemical safety assessment according to Annex I indicate the need to further investigate the effects on aquatic organisms.

 

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 2016), the quantitative chemical safety assessment (conducted according to Annex I of REACH) indicates that no hazard is identified: the Risk Characterisation Ratio is well below 1, even with due consideration of contributing uncertainties, and therefore the risk is already adequately controlled and therefore further testing is not justifiable.

 

The substance is highly water-soluble, has low potential for bioaccumulation (based on log K_ow <3 (-2.9)) and there is no reason to expect any specific mechanism of toxicity beyond narcosis. Therefore, the occurrence of toxic effects during long-term testing, that were absent in the existing short-term aquatic studies (conducted at concentrations up to 120 mg/l of parent substance), would be considered unlikely.

 

Based on the acute aquatic data, read across from a structural analogue, no short-term effects were seen in any trophic level, although a chronic endpoint NOEC of 60 mg/l was reported in the algal test. Thus, toxicity of 3-(trihydroxysilyl)propiononitrile to fish species is not expected.

 

A PNEC has been derived for the purpose of chemical safety assessment. An assessment factor of 1000 was applied to derive the freshwater PNEC. This high assessment factor to derive the predicted no-effect level already reflects the typically higher value of a short-term EC₅₀ compared to a long-term NOEC/EC₁₀. 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/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 9 and 10 of the Chemical Safety Report, respectively.