(3-chloropropyl)triethoxysilane

Endpoint summary

Additional information

One reliable short-term toxicity test result is available with the registered substance, (3-chloropropyl)triethoxysilane (CAS 5089-70-3, EC 225-805-6) for freshwater invertebrates (Daphnia magna) that represents exposure of the test organisms to the parent substance. The relevant short-term value is :

Daphnia: EC₅₀ (48 h): 21.2 mg/l (nominal, measured values were within 20% of nominal values), expressed in terms of the concentration of the parent substance.

This value is supported with data from studies conducted with the registered substance (3-chloropropyl)triethoxysilane (CAS 5089-70-3) for freshwater fish (Danio rerio), invertebrates (Daphnia magna) and algae (Scenedesmus subspicatus (new name: Desmodesmus subspicatus)) that represent exposure of the test organisms to a mixture of the parent substance and its hydrolysis products, (3-chloropropyl)silanetriol and ethanol. The relevant short-term values are:

Fish: LC₅₀ (96 h): 80 mg/l, expressed in terms of the concentration of the parent substance;

Daphnia: EC₅₀ (48 h): 140 mg/l, expressed in terms of the concentration of the parent substance;

Algae: E_rC₅₀ (72 h): >819 mg/l, expressed in terms of the concentration of the parent substance.

The relevant long-term value is:

Algae: NOE_rC (72 h): 237 mg/l, expressed in terms of the concentration of the parent substance.

Results from these data are currently used for the derivation of aquatic PNECs. New studies will be conducted with the parent substance, (3-chloropropyl)triethoxysilane (CAS 5089-70-3), for the following endpoints: short-term toxicity to fish and toxicity to aquatic algae. Long-term aquatic toxicity studies will be proposed (depending on the results of the new short-term studies).

Because it is likely that the current data reflect exposure to a mixture of the parent substance and the hydrolysis products initially, then the hydrolysis products by the end of the exposure, read-across has been used to provide information for the assessment of the toxicity of the silanol hydrolysis product.

Reliable short-term toxicity tests have been read-across from (3-chloropropyl)trimethoxysilane (CAS 2530-87-2, EC 219-787-9) for freshwater fish (Danio rerio), invertebrates (Daphnia magna) and algae (Scenedesmus subspicatus (new name: Desmodesmus subspicatus)). The relevant short-term values are:

Fish: LC₅₀ (96 h): >79 mg/l, expressed in terms of the concentration of the silanol hydrolysis product, (3-chloropropyl)silanetriol;

Daphnia: EC₅₀ (48 h): 685 mg/l, expressed in terms of the concentration of the silanol hydrolysis product, (3-chloropropyl)silanetriol;

Algae: E_rC₅₀ (72 h): >657 mg/l, expressed in terms of the concentration of the silanol hydrolysis product, (3-chloropropyl)silanetriol.

The relevant long-term value is:

Algae: E_rC₁₀ (72 h): 405 mg/l, expressed in terms of the concentration of the silanol hydrolysis product, (3-chloropropyl)silanetriol.

A reliable long-term toxicity to aquatic invertebrates study is available with the registration substance, (3-chloropropyl)triethoxysilane for Daphnia magna. Exposure of the test organisms was primarily to the hydrolysis products, (3-chloropropyl)silanetriol and ethanol. The long-term value is:

Daphnia: NOEC (21 d): =66 mg/l, expressed in terms of the concentration of the silanol hydrolysis product, (3-chloropropyl)silanetriol.

Results from the read-across data and long-term toxicity to aquatic invertebrates data conducted with the registration substance will be used for the derivation of sediment and soil PNECs.

An activated sludge respiration inhibition 3-hour NOEC value of 320 mg/l was determined for the registered substance, (3-chloropropyl)triethoxysilane (CAS 5089-70-3; EC No. 225-805-6), in a reliable study conducted according to an appropriate test protocol (OECD 209), and in compliance with GLP.

Refer to IUCLID Section 6 endpoint summary (CSR Section 7.0) for further discussion of the approach to chemical safety assessment and justification for read across.