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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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There are no data describing the long-term toxicity of the registration substance to soil macroorganisms except arthropods. Earthworm reproduction studies are proposed for the structural analogue, silsesquioxanes, phenyl (CAS 70131-69-0).

In the interim period, before the data with phenyl silsesquioxanes become available, data are available for the siloxane decamethylcyclopentasiloxane (D5, CAS 541 -02 -6).

A 28-day LC50 value 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 test substance on mortality and reproduction and growth respectively of Eisenia andrei.

No effects at the highest concentration tested were also determined in a second test with D5: 28-d F0 LC50 values  of >76 mg/kg nominal concentration, >41 mg/kg mean measured concentration, and NOECs of 76 mg/kg nominal concentration, and 41 mg/kg mean measured concentration, have been determined for effects of D5 on survival and weight change of adult earthworms.

56-d F1 LC50 values  of >76 mg/kg nominal concentration, >41 mg/kg mean measured concentration, and NOECs of 76 mg/kg nominal concentration, and 41 mg/kg mean measured concentration, have been determined for effects of D5 on reproduction of the earthworm Eisenia fetida.

Read-across of the terrestrial toxicity data for D5 to 1,3,5-trimethyl-1,1,3,5,5-pentaphenyltrisiloxane (CAS 3390-61-2) is considered to be suitable to derive an interim hazard and risk assessment under REACH for the registration substance.

Refer to Section 6.3 for further discussion.