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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

Key value for chemical safety assessment

Additional information

The following information is taken into account for any hazard / risk / persistency assessment:

The chemical safety assessment according to Annex I indicates that it is not necessary to conduct the simulation test on ultimate degradation in surface water and the sediment simulation test, or to identify degradation products.

Simulation tests (water and sediments) are not considered necessary because:

  • The substance is used under highly controlled conditions and, therefore, exposure of the aquatic environment is low (see Section 9 for further details).

  • The substance and its likely hydrolysis products are unstable. The registered substance will hydrolyse rapidly in contact with water. The interim hydrolysis products are progressively shorter alpha-omega siloxanediols and the most likely ultimate hydrolysis product is methylsilanetriol. The risk characterisation ratios (RCRs) for the aquatic and sediment compartment, even with the conservative assumption that the silanol hydrolysis product is not biodegradable, are <1. At higher concentrations, polymeric species are expected to dominate.