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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

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Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

A 14-day LC50 value of >1000 mg/kg dry weight and NOEC of =1000 mg/kg dry weight have been determined for the effects of the test substance on mortality of Eisenia fetida. It is likely that the test organisms were exposed primarily to the hydrolysis products of the test substance. The 14-day LC50 is equivalent to >830 mg/kg dwt when expressed in terms of the silanol hydrolysis product, 3-(trihydroxysilyl)propyl methacrylate.

A 28-day EC50 620 mg/kg dwt and EC25 359 mg/kg dwt (nominal) have been determined for the effects of the test substance on nitrogen transformation by terrestrial microorganisms (OECD 216). A NOEC of 100 mg/kg dwt (nominal) was derived for the study. It is likely that the test organisms were exposed primarily to the hydrolysis products of the test substance. The 28-day results are equivalent to EC50 of 515 mg/kg dwt and EC25 of 298 mg/kg dwt, and the study NOEC is equivalent to 83 mg/kg dwt, when expressed in terms of the silanol hydrolysis product, 3-(trihydroxysilyl)propyl methacrylate.

Approach to the Terrestrial Chemical Safety Assessment

 

The registered substance, 3-trimethoxysilylpropyl methacrylate (CAS 2530-85-0, 219-785-8), will hydrolyse rapidly (half-life 1.87 hours at pH 7 and 20°C) in contact with water and atmospheric moisture to 3-(trihydroxysilyl)propyl methacrylate and methanol. REACH guidance (ECHA 2016, R.16) states that “for substances where hydrolytic DT50 is less than 12 hours, environmental effects are likely to be attributed to the hydrolysis product rather than to the parent itself”. ECHA Guidance Chapter R.7b (ECHA, 2017) states that where degradation rates fall between >1 hour and <72 hours, testing of parent and/or degradation product(s) should be considered on a case-by-case basis. Therefore, in accordance with REACH guidance, the environmental hazard assessment, including sediment and soil compartments due to water and moisture being present, is based on the properties of the silanol hydrolysis product 3-(trihydroxysilyl)propyl methacrylate.

The non-silanol hydrolysis product, methanol, is not expected to contribute to toxicity to terrestrial organisms. 

 

Hydrolysis product: 3-(trihydroxysilyl)propyl methacrylate

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 to invertebrates/higher plants study because, as indicated in guidance R.7.11.6 (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 not readily biodegradable but is highly water soluble and has a low potential for adsorption (based on log Kow <3 (-0.9) and log Koc 0.6), therefore exposure of the terrestrial compartment is expected to be low. No toxicity was observed in short-term aquatic tests conducted with the registered substance (and exposure was to the hydrolysis products, 3-(trihydroxysilyl)propyl methacrylate and methanol) and the occurrence of more severe toxic effects in the terrestrial compartment that were not expressed in the aquatic studies would be considered unlikely.

Reliable terrestrial toxicity tests to soil macroorganisms except arthropods (earthworms, short-term) and soil microorganisms are available for the registered substance, in which exposure was predominantly to the hydrolysis products, 3-(trihydroxysilyl)propyl methacrylate and methanol. No toxicity was observed in the toxicity to soil macroorganisms except arthropods study, therefore the PNECsoil has been calculated by applying an assessment factor of 1000 to the 28-day soil microorganisms EC50 value of 515 mg/kg dwt (expressed in terms of the silanol hydrolysis product).

 

Overall, it is concluded that the risk characterisation conclusion is sufficiently conservative 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, CSR Section 7, and Chapters 9 and 10 of the Chemical Safety Report, respectively.