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Additional information

The distribution in a sewage treatment plant (STP) has been estimated using the SimpleTreat model (implemented in EUSES 2.1.2), see table below. Due to the very rapid hydrolysis of tert-butyl(chloro)dimethylsilane, the distribution calculation is done for the silanol hydrolysis product, tert-butyl(dimethyl)silanol.

Table: Distribution modelling for STP

Fraction of emission directed to water by STP

88.22

[%]

Fraction of emission directed to air by STP

9.27

[%]

Fraction of emission directed to sludge by STP

2.51

[%]

Fraction of the emission degraded in STP

0

[%]

tert-Butyl(chloro)dimethylsilane hydrolyses very rapidly to form tert-butyl(dimethyl)silanol and hydrochloric acid. Ready biodegradation is not relevant for hydrochloric acid being inorganic. tert-Butyl(dimethyl)silanol is not expected to undergo any significant biodegradation and is predicted to have low Henry’s Law constant and low log Kow/log Koc. Distribution modelling for STP indicates that water is the main compartment to which it is expected to partition in a sewage treatment plant. Water is also likely to be the main compartment to which tert-butyl(dimethyl)silanol will partition in the wider environment.