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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: Not readily biodegradable: 0% biodegradation (inorganic carbon analysis) in 28 days (OECD 310), read-across from a structurally-related substance.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

No data are available for the submission substance, 2,4,6,8,10-penta methylcyclopentasiloxane.

However, the substance is predicted to hydrolyse rapidly to methylsilanediol, which is then expected to hydrolyse further to methylsilanetriol.

Therefore, good quality data for the structurally-related substance trimethylsilanol (CAS 1066-40-6), have been read across.

Methylsilanetriol and trimethylsilanol are within ananalogue group of substances. Within this analogue group, in general, the substances exhibit no evidence of any significant biodegradation once hydrolysis and subsequent biodegradation of alkoxy/acetoxy groups has been taken into account.

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

0% degradation in 28 days (inorganic carbon analysis) was determined for trimethylsilanol.

References:

PFA (2013f), Peter Fisk Associates, Biodegradation Main Analogue Group report, PFA.300.005.007.