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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance is highly insoluble in water, hence indicating that aquatic toxicity is unlikely to occur
other:

Description of key information

Key value for chemical safety assessment

Additional information

No reliable toxicity to aquatic invertebrates data are available for 2,4,6-trimethyl-2,4,6-tris(3,3,3-trifluoropropyl)cyclotrisiloxane (CAS 2374-14-3).

 

Testing is not required for the following reasons:

- It is technically not feasible to conduct an aquatic study due to the very low water solubility of the substance (1.3E-06 mg/l) and very high log Kow (9). These values indicate that maintaining stable aqueous test solutions will be extremely difficult. This was confirmed by the attempted long-term study with Daphnia magna. Furthermore, once dissolved, the substance will have the tendency to adsorb onto the glassware under experimental conditions and onto dissolved organic matter in the natural environment.

- Above a log Kow of 6 short-term toxicity effects are not expected, because the very limited aqueous solubility prevents toxic concentrations being achieved in exposure media.

- The long-term Daphnia test performed at the limit of functional water solubility showed no acute effects.

- The physicochemical properties and very high value of Koc (6) means that if the substance could enter a wastewater treatment plant in influent waste waters, it would partition mainly to sludge (a small proportion may be volatilised), with a negligible amount passing to water. The result is that exposure of freshwater or marine aquatic compartments is negligible.

- The substance is not manufactured or used as such in the EU and is registered in accordance with the REACH Regulation (Article 6) in order to support import of polymers. Residual unbound monomer in polymer is very low and the substance is of extremely low water solubility, such that unintentional release to the aquatic environment from end use of the polymers is negligible.