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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Endpoint summary

Administrative data

Description of key information

Additional information

Reliable short-term toxicity tests results are available for freshwater fish (Danio rerio), invertebrates (Daphnia magna) and algae (Pseudokirchneriella subcapitata) with tetraethyl orthosilicate (CAS 78-10-4; EC No. 201-083-8). The relevant short-term values are:

Fish: LC50 (96 h): >245 mg/l (measured DOC) (>113 mg/l when expressed in terms of concentration of the hydrolysis product, monosilicic acid) (Hüls, 1993).

Daphnia: EC50 (48 h): >844 mg/l (based on DOC analysis of initial stock solution) (>389 mg/l when expressed in terms of concentration of the hydrolysis product, monosilicic acid) (Hüls, 1989).

EC50 (48 h): >75 mg/l (measured concentration, based on analysis of the parent substance by GC/FID) (highest measured concentration tested) (test guideline OECD TG 202 (Daphnia sp. Acute immobilisation test)).

Algae: EC50 (72 h): >100 mg/l; NOEC: ≥100 mg/l (nominal) (EC50 >46 mg/l and NOEC ≥46 mg/l when expressed in terms of concentration of the hydrolysis product, monosilicic acid) (Springborn Smithers, 2008).

The rapid hydrolysis of tetraethyl orthosilicate (CAS 78-10-4) (half-life 4.4 hours at pH 7 and 20-25°C) indicates that, under conditions relevant to ecotoxicity assessment, it will hydrolyse to monosilicic acid (CAS 10193-36-9; EC No. 233-477-0) and ethanol (CAS 64-17-5; EC No. 200-578-6) over the course of the tests and therefore the test organisms in each test were exposed primarily to the hydrolysis products, with the exception of the flow-through Daphnia test in which the organisms were exposed to a mixture of the parent substance and its hydrolysis products.

Reliable toxicity to microorganisms data are available with tetraethyl orthosilicate (CAS 78-10-4); a 3-hour EC50 value of >100 mg/l has been derived for the effects of the substance on respiration of activated sludge (Desmares-Koopmans, 2010).

Refer to IUCLID Section 6, CSR Section 7.0, for further discussion of the approach to chemical safety assessment.