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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Biodegradation in water: screening tests: 51% biodegradation (DOC removal) in 28 days (EU C.4-A), based on read-across from an analogous substance.No significant biodegradation of the silanol hydrolysis product, 3 -(trihydroxysilyl)propanethiol, is expected.

Key value for chemical safety assessment

Additional information

There are no reliable ready biodegradation data available for 3 -(triethoxysilyl)propanethiol, therefore good quality data for the analogous substance,

3 -(trimethoxysilyl)propanethiol

, (CAS 4420-74-0), have been read across. Both substances share the same silanol hydrolysis product,

3 -(trihydroxysilyl)propanethiol

l; the other hydrolysis products being ethanol and methanol, respectively, both of which are readily biodegradable.

3 -(Triethoxysilyl)propanethiol

and

3 -(trimethoxysilyl)propanethiol

e are within an analogue group of substances within which, in general, there is no evidence of any significant biodegradation once biodegradation of alkoxy/acetoxy groups has been taken into account.

It is therefore considered valid to read-across the results for

3 -(trimethoxysilyl)propanethiol

to fill the data gap for the registered substance. Additional information is given in a supporting report (PFA, 2013f) attached in Section 13 of the IUCLID 5 dossier.

3 -(Trimethoxysilyl)propanethiol attained

51% biodegradation in 28 days. This biodegradation is attributable to the biodegradation of the methanol hydrolysis product. No significant biodegradation is expected for the silanol hydrolysis product.