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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Reference
Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:

Description of key information

Key value for chemical safety assessment

Additional information

Testing for toxicity to terrestrial organisms is not considered necessary because:

In accordance with Column 2 of REACH Annex IX, there is no need to further investigate the effects of this substance in a long or short-term terrestrial toxicity study because, as indicated in guidance R.7.11.6 (ECHA 2016), 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 silanol hydrolysis product is not readily biodegradable but has low potential for bioaccumulation (based on log Kow <3 (-2.9)) and there is no reason to expect any specific mechanism of toxicity beyond narcosis. The low log Kow indicates that partitioning to the terrestrial compartment is expected to be minimal.

Short-term toxicity testing has been carried out with a structural analogue of the registered substance. During these tests, it is likely that organisms were exposed to the parent substance and some hydrolysis product of the test substance during the fish and Daphnia tests, and mostly the hydrolysis products during the algal test. The occurrence of more severe toxic effects in the terrestrial compartment that were not expressed in these aquatic studies (conducted at concentrations of parent substance loaded up to 120 mg/l) would be considered unlikely.

 

PNECsoil has been calculated from the aquatic data on the basis of the equilibrium partitioning method. The PNEC calculated by Equilibrium Partitioning has been derived for the purpose of chemical safety assessment and the risk characterisation ratios are below 1.

 

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

 

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.