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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Reliable terrestrial toxicity data are available with triethoxy(octyl)silane (CAS 2943-75-1, EC No. 220-941-2) for toxicity to soil organisms except arthropods (OECD TG 222) and toxicity to soil microorganisms (OECD TG 216).  

The key values for chemical safety assessment are:

OECD TG 222 Earthworm reproduction test:

            28-day NOEC value for adult Eisenia fetida survival: 308.6 mg/kg dry substrate

            28-day LC10 value for adult Eisenia fetida survival: 351.7 mg/kg dry substrate

            NOEC value based on reproduction: 308.6 mg/kg dry substrate

            EC10 value for effects on reproduction: 44.71 mg/kg dry substrate

These results are based on nominal test substance concentrations. It is likely that the test organisms were exposed to parent substance at the beginning of the test, with increasing amounts of hydrolysis products as the study progressed.

 

OECD TG 216 Soil nitrogen transformation test:

A 28-day NOEC value of 320 mg/kg dry weight (nominal) has been determined for the effects of triethoxy(octyl)silane on the nitrogen transformation rate of terrestrial microorganisms.

These results are based on nominal test substance concentrations. It is likely that the test organisms were exposed to parent substance at the beginning of the test, with increasing amounts of hydrolysis products as the study progressed.

 

Triethoxy(octyl)silane (CAS 2943-75-1) falls under soil Hazard Category 3 (indication for high adsorption based on log Kow >3, but no indication of aquatic toxicity (no effects in aquatic studies)). For Hazard Category 3 substances, a confirmatory long-term study is required: the above reported OECD TG 222 study was conducted. ECHA guidance Chapter R.7c (ECHA 2017) states the following: “If PEC/PNECscreen >1 or indication of risk from confirmatory long-term soil toxicity test: Conduct long-term toxicity tests according to the standard information requirements Annex X (invertebrates and plants), choose lowest value for derivation of PNECsoil”.

In accordance with the ECHA guidance, because effects were observed in the OECD TG 222 earthworm study as well as the soil microorganisms study, a long-term toxicity to terrestrial plants study is required.

A long-term toxicity to terrestrial plants study in accordance with OECD TG 208 is therefore proposed with triethoxy(octyl)silane (CAS 2943-75-1, EC No. 220-941-2) and is awaiting approval by ECHA.