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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Description of key information

Short-term toxicity to terrestrial invertebrates: LC50 (28-day): >4074 mg/kg dry weight, Eisenia andrei, read-across from an analogous substance, decamethylcyclopentasiloxane (D5, CAS 541-02-6) within the Reconsile Siloxanes Category.

Long-term toxicity to terrestrial invertebrates: NOEC (56-day): ≥4074 mg/kg dry weight for effects on reproduction and growth, Eisenia andrei, read-across from an analogous substance, decamethylcyclopentasiloxane (D5, CAS 541-02-6) within the Reconsile Siloxanes Category.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
4 074 mg/kg soil dw
Long-term EC10, LC10 or NOEC for soil macroorganisms:
4 074 mg/kg soil dw

Additional information

There are no data describing the long-term toxicity of the registration substance to soil macroorganisms. However, data are available within the Siloxanes Category for the siloxane decamethylcyclopentasiloxane (D5, CAS: 541-02-6). A 28-day LC50value of >4074 mg/kg dry weight and a 56-day NOEC of ≥4074 mg/kg dry weight have been determined for the effects of the read-across substance on mortality and reproduction and growth respectively of Eisenia andrei.

An earthworm reproduction study has already been proposed for a structurally-similar substance within the Siloxanes Category, Silsesquioxanes, Phenyl (CAS 70131-69-0). The approach to chemical safety assessment for octaphenylcyclotetrasiloxane will be reconsidered once further data becomes available.

Read-across of the terrestrial toxicity data for D5 to octaphenylcyclotetrasiloxane is considered to be suitable as an interim approach for the purpose of chemical safety assessment.

Refer to Section 6.3 for further discussion.