Tris(2-methoxyethoxy)vinylsilane

Toxicity to terrestrial plants

Description of key information

A NOEC of =100 mg/kg dwt has been determined for the effects of the test substance on emergence of Triticum aestivum, Lepidium sativum and Brassica alba seedlings. 17-day EC₅₀ values for effects on growth of the three species were 29, 94 and >100 mg/kg dwt respectively. The NOEC is equivalent to =38 mg/kg d.w. and the EC₅₀ values are equivalent to 11, 36 and 38 mg/kg dwt, respectively, when expressed in terms of the silanol hydrolysis product.

Additional information

The need for long-term testing in terrestrial plants is waived because application of the equilibrium partitioning method indicates that the substance is of low risk to terrestrial plants. This conclusion is supported by the existing short-term data.

Test data are only available for short-term toxicity to terrestrial plants. A NOEC of =100 mg/kg dwt has been determined for the effects of the test substance on emergence of Triticum aestivum, Lepidium sativum and Brassica alba seedlings. 17-day EC₅₀ values for effects on growth of the three species were 29, 94 and >100 mg/kg dwt, respectively (determined graphically). The effect concentrations can be expressed in terms of the silanol hydrolysis using the following calculation: (MW hydrolysis product / MW parent ) * effect concentration = effect concentration in terms of the silanol hydrolysis product.

The NOEC is equivalent to =38 mg/kg dwt and the EC₅₀ values are equivalent to 11, 36 and >38 mg/kg dwt, respectively, when expressed in terms of the silanol hydrolysis product.

17-day LOECs for growth are reported as 10 mg/kg, 100 mg/kg and >100 mg/kg dwt respectively in Triticum aestivum, Lepidium sativum and Brassica alba (determined by t-test based on mean plant weight). These values are equivalent to 3.8, 38 and >38 mg/kg dwt respectively, when expressed in terms of the silanol hydrolysis product. Whilst indicative NOECs can therefore be determined as 1 mg/kg, 10 mg/kg and >10 mg/kg dwt (or 0.38, 3.8 and >38 mg/kg dwt in terms of the silanol hydrolysis product), this would be a highly conservative interpretation in view of the unusually large spacing of the dose levels for a test of this type (spacing factor of 10; OECD 208 recommends spacing factor should not exceed 3). The study is not supported by analytical work and no information is reported relating to the OECD 208 validity criterion for normal growth, morphology and lack of visible signs of phytotoxicity. This study was assigned a reliability 2 score because it is a guideline study conducted in accordance with GLP however, the dose spacing is very large, analytical verification was not performed, and some details are not available to assess validity against criteria of OECD 208.

OECD 208 is technically a short-term study, designed to assess the potential effects of substances on seedling emergence and growth. Therefore, it is specific to a part of the plants life-cycle and does not cover chronic effects or effects on reproduction; however, as ECHA guidance on information requirements and chemical safety assessment makes clear, this test is assumed to cover a sensitive stage in the life-cycle of a plant and therefore data obtained from this study can be used as estimates of chronic toxicity. A full life cycle higher plant test is not usually a REACH requirement and is not recommended in this case.