Disilane, chloro Me derivs.

Biodegradation in water: screening tests

Description of key information

Biodegradation in water, screening tests: Not readily biodegradable: 0% (inorganic carbon analysis) in 28 days (OECD 310) for read-across substance trimethylsilanol.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The submission substance is a multiconstituent substance with three major constituents: 1,2-dichloro-1,1,2,2-tetramethyldisilane, 1,1,2-trichloro-1,2,2-trimethyldisilane and 1,1,2,2-tetrachloro-1,2-dimethyldisilane. No data are available for the submission substance. However, the substance hydrolyses very rapidly in contact with water to give

the silanol derivatives of the three constituents, 1,2-dihydroxy-1,1,2,2-tetramethyldisilane, 1,1,2-trihydroxy-1,2,2-trimethyldisilane and 1,1,2,2-tetrahydroxy-1,2-dimethyldisilane.

A reliable study conducted according to an appropriate test protocol (OECD 310), and in compliance with GLP is available for trimethylsilanol, which is a close structural analogue of the hydrolysis products of the three constituents. This is selected as the key study. Biodegradation is not relevant for hydrogen chloride as it is inorganic.

The use of such read-across is supported by evidence that within a category of small molecule silicon-dominated organosilicon compounds, without reactive functional groups in the side chain, there is no evidence of any significant biodegradation in ready biodegradation tests (Data gap filling report for ready biodegradability of silicon-dominated substances PFA.151.004.022A).