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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Link to relevant study record(s)

Description of key information

NOEC (72 h): >= 2 µg/l (read-across from dodecamethylcyclohexasiloxane)

Key value for chemical safety assessment

Additional information

No data are available for the toxicity of phenyl silsesquioxanes (EC No. 939-487-8) to aquatic algae.

However, the constituents have a very high log Kow value (9.0) and long-term toxicity is unlikely to be expressed. This is supported by read-across from decamethyltetrasiloxane (L4, CAS 141-62-8, EC No. 205-491-7, log Kow 8.2) and dodecamethylcyclohexasiloxane (D6, 540-97-6, EC No. 208-762-8, log Kow 9) where no effects have been reported at the limit of solubility in algal inhibition studies. 72-hour NOEC values of ≥2.2 μg/l and ≥2 μg/l have been reported on the effects of L4 and D6 respectively on growth rate of Pseudokirchneriella subcapitata. The read-across data from surrogate substances having similar physico-chemical properties indicate no toxicity at the limit of solubility.

Data with L4 and D6 are also read across to the long-term toxicity to fish and invertebrates endpoints, where experimental studies are available with the registration substance itself. No effects were reported at the limit of solubility of the substances in any of the studies. The fish and invertebrates data support the approach to read-across for the toxicity to aquatic algae endpoint by showing that effects (or lack of) are consistent in the studies with phenyl silsesquioxanes, L4 and D6.