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Short-term toxicity to fish data are available with the registration substance:

A 14 day EC50 value of >159 ng/l and a NOEC value of 159 ng/l (highest concentrations tested), based on mean measured concentrations, have been determined for the effects of the test substance on sublethal effects and mortality of Oncorhynchus mykiss, in accordance with OECD Guideline 204.

The test solution preparation method and test system design indicate that the test organisms were predominantly exposed to the parent substance.

A 96 hour LC50 value of >182 ng/l and a NOEC value of 182 ng/l (highest concentrations tested), based on mean measured concentrations, have been determined for the effects of the test substance on mortality of Oncorhynchus mykiss, in accordance with OECD Guideline 203. All fish in the control and treatment groups appeared normal throughout the test and showed no overt signs of toxicity.

The test solution preparation method and test system design indicate that the test organisms were predominantly exposed to the parent substance.

Algal data are available, read across from structurally similar substance 3,3-bis[(dimethylvinylsilyl)oxy]-1,1,5,5-tetramethyl-1,5-divinyltrisiloxane (CAS 60111-54 -8):

A 72-hour EC50 value of >15 ng/l and NOEC of ≥15 ng/l have been determined for the effects of the read-across substance, 3,3-bis[(dimethylvinylsilyl)oxy]-1,1,5,5-tetramethyl-1,5-divinyltrisiloxane (CAS 60111-54 -8) on growth rate of Pseudokirchneriella subcapitata. The test substance has a water solubility of <10 ng/l and therefore the results indicate that it is not toxic at its solubility limit.

A long-term toxicity to invertebrates study with Daphnia magna is available with the registration substance. The relevant long-term data are:

A 21 day EC50 value of >191 ng/l, a NOEC value of 191 ng/l and a LOEC value of >191 ng/l (highest concentrations tested), based on mean measured concentrations, have been determined for the effects of the test substance on survival, growth and reproduction of Daphnia magna, in accordance with OECD Guideline 211.

The test solution preparation method and test system design indicate that the test organisms were predominantly exposed to the parent substance.

Although it is not an annex requirement for this substance, long-term sediment toxicity data are also available. Due to the low solubility, high log Kow and high adsorption potential of the registration substance, testing with sediment organisms is relevant:

A 28 day EC50 value of >56 mg/kg sediment dry weight, a NOEC value of 56 mg/kg sediment dry weight and a LOEC value of >56 mg/kg sediment dry weight (highest concentration tested) based on mean measured concentrations have been determined for the effects of the test substance on emergence of Chironomus riparius, in accordance with OECD Guideline 218.

A 28 day EC50 value of >56 mg/kg sediment dry weight (highest concentration tested), a NOEC value of 10 mg/kg sediment dry weight and a LOEC value of 17 mg/kg sediment dry weight based on mean measured concentrations have been determined for the effects of the test substance on development of Chironomus riparius, in accordance with OECD Guideline 218.

The author notes that the midge emergence development rate NOEC with measured concentrations is slightly lower than the calculated M4Q sediment solubility limit of 15 mg/kg-dw. The Lowest-Observed-Effect Concentration (LOEC) for midge emergence and combined midge development rate, based on the mean measured concentrations of applied test substance, was established to be >56 and 17 mg/kg, respectively. As the midge development LOEC value is approximately equivalent to the calculated M4Q sediment solubility limit of 15 mg/kg-dw, physical deposition of the chemical in sediment may be adversely affecting midge development.

Refer to IUCLID Section 6 endpoint summary for further discussion of the approach to chemical safety assessment and justification for read across.