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Environmental fate & pathways

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The distribution in a sewage treatment plant (STP) has been estimated using the SimpleTreat model (implemented in EUSES 2.1.2/Chesar 3.5), see table below. Due to the rapid hydrolysis of the parent substance, the distribution calculation is done for the hydrolysis products, 3-(trihydroxysilyl)propyl methacrylate and methanol.

Table: Distribution modelling for STP

 

3-(Trihydroxysilyl)propyl methacrylate

Methanol

 Unit

Release directed to water

99.95

12.62

[%]

Release directed to air

8.84E-10

0.095

[%]

Release directed to sludge

0.044

0.037

[%]

Release degraded

0

87.24

[%]

3-Trimethoxysilylpropyl methacrylate hydrolyses rapidly to 3-(trihydroxysilyl)propyl methacrylate and methanol. 3-Trimethoxysilylpropyl methacrylate is readily biodegradable but failing the 10-day window. Once the biodegradation of the alkoxy groups is taken into account, there is evidence that the methacrylate side-chain is biodegrading to some extent, but as a worst-case; 3-(trihydroxysilyl)propyl methacrylate is considered to be not biodegradable. Methanol is readily biodegradable.

3-(Trihydroxysilyl)propyl methacrylate has very low Henry’s Law Constant, and low log Kow/log Koc. Distribution modelling for STP indicates that water is the main compartment to which 3-(trihydroxysilyl)propyl methacrylate is expected to partition in a sewage treatment plant. Water is also likely to be the main compartment to which it will partition in the wider environment.