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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Toxicity to terrestrial plants

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Administrative data

Link to relevant study record(s)

Description of key information

There are no data for the substance. A 17-day NOEC of ≥100 mg/kg soil dry weight has been determined for the effects of the read-across substance Trimethoxy(2-methylpropyl)silane (CAS 18395-30-7) on emergence and growth of Triticum aestivum (wheat), Lepedium sativum (cress) and Brassica alba (mustard) seedlings.

Key value for chemical safety assessment

Additional information

No test data for toxicity to terrestrial plants are available for Trichloroisobutylsilane.  

However, short-term toxicity data are available for the related substance Trimethoxy(2-methylpropyl)silane. Trichloroisobutylsilane (CAS 18169-57-8) and Trimethoxy(2-methylpropyl)silane (CAS 18395-30-7) both hydrolyse to Isobutylsilanetriol. The hydrolysis half-lives of Trichloroisobutylsilane and Trimethoxy(2-methylpropyl)silane indicate that, under conditions relevant to ecotoxicity assessment, they will hydrolyse to Isobutylsilanetriol over the course of the tests. The other hydrolysis products are hydrogen chloride and methanol, respectively; the properties of these substances are well characterised. Methanol is non-toxic to the environment and it is considered unlikely that its presence significantly affected the results of the test performed with Trimethoxy(2-methylpropyl)silane. Effects of hydrogen chloride are limited to those that result from changes to pH and these would not be expected to occur in soil.

Further testing for terrestrial toxicity (including long-term testing with plants) is not considered necessary because:

- The substance hydrolyses rapidly in contact with water and the log Kowof the hydrolysis product is <3.

- The substance is used under highly controlled conditions and, therefore, exposure of soil is low.

- PNECsoil has been calculated from PNECfreshwater on the basis of the equilibrium partitioning method; the risk characterisation ratios (RCR) based on PNECsoil derived from this method are <1.