Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Data are available for short-term toxicity of the registered substance to fish. A 96 hour LC50 value of >75 ng/L has been determined for effects on mortality of Oncorhynchus mykiss based on mean measured concentrations of the substance in a flow-through test. There are no short-term toxicity data for aquatic invertebrates and algae.

Long-term toxicity data are available for invertebrates, no effects were seen in the long-term study, up to the limit of solubility.

A 21 day EC50 of >47 ng/l and NOEC of ≥47 ng/l have been determined for the effects of the test substance on adult mortality, reproduction and growth of Daphnia magna. The data have been obtained in flow-through tests and are expressed relative to mean measured concentrations of the substance.

These concentrations were measured in test media prepared at a nominal concentration that corresponded with the water solubility of the substance (70 ng/l).

The key result for long-term toxicity in fish is good quality data for the structurally-related substance, decamethyltetrasiloxane (CAS 141-62-8). A 60 day post-hatch NOEC of ≥7.9 µg/l (time weighted mean measured) has been determined for the effects of the structurally-analogous substance, decamethyltetrasiloxane (CAS 141-62-8) on hatching, larval survival, abnormal appearance and behaviour in Oncorhynchus mykiss in the fish early-life stage test (OECD 210).

Short-term aquatic toxicity data for invertebrates is not required because reliable long-term aquatic toxicity data for invertebrates is available.

No data are available with the registered substance on algal inhibition. However, data are available with a structural analogue, decamethyltetrasiloxane (L4, CAS 141-62-8). A 72 hour EC50 value of >2.2 μg/l and NOEC of ≥2.2 μg/l have been determined for the effects of decamethyltetrasiloxane on growth rate of the freshwater algae Pseudokirchneriella subcapitata, based on geometric mean measured concentrations.

Measured long-term sediment toxicity data are available with L5 for three sediment dwelling species; Lumbriculus variegatus, Chironomids riparius and Hyalella azteca:

WoE: 28 day NOEC ≥38 mg/kg dry weight normalised to 5% organic carbon, based on mean measured concentrations, for the effects of L5 on survival and biomass of Lumbriculus variegatus.

WoE: 28 day NOEC ≥27 mg/kg dry weight normalised to 5% organic carbon, based on mean measured concentrations, for the effects of L5 on emergence and combined developmental rate of Chironomus riparius.

WoE: 28 day NOEC ≥59 mg/kg dry weight normalised to 5% organic carbon, based on mean measured concentrations, for the effects of L5 on survival and growth of Hyalella azteca.

There are no reliable data available for toxicity to microorganisms.

A 3 hour EC50 value of >100 mg/l (ASRI) is read-across from the structurally-related substance L4 (CAS 141 -62 -8).