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Ecotoxicological information

Sediment toxicity

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Reference
Endpoint:
sediment toxicity: 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

No sediment toxicity data are available with the registered substance.  

In accordance with Column 2 of REACH Annex IX, there is no need to further investigate the effects of this substance in long-term sediment toxicity studies because, as discussed in guidance R.7.8.10 (ECHA 2017), the quantitative chemical safety assessment (conducted according to Annex I of REACH) indicates that the Risk Characterisation Ratio is well below 1, and therefore the risk is already adequately controlled and further testing is not justifiable.

The silanol hydrolysis product, [3-(2,3-epoxypropoxy)propyl]silanetriol, upon which the chemical safety assessment is based, is highly water soluble and has a low log Kow value and therefore, exposure of and accumulation in the sediment compartment is expected to be low.

The substance is not adsorbing (based on log Koc -0.33) and has low bioavailability (based on log Kow <3 (-2.6)). Toxicity to fish was observed in the short-term aquatic tests, which may be due to the presence of an epoxide ring which is a known structural alert for fish. However, invertebrates and algae showed low/no toxicity in short and long-term tests, therefore, the occurrence of more severe toxic effects in the sediment compartment that were not expressed in the aquatic studies would be considered unlikely.

The PNEC calculated by the Equilibrium Partitioning Method has been determined for the purpose of deriving a 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.