Dichloro(3-chloropropyl)methylsilane

Toxicity to aquatic algae and cyanobacteria

Description of key information

72 h E_rC₅₀: 437 mg/l S. subspicatus (read-across from CAS 13501-76-3), or 321 mg/l when expressed in terms of the silanol hydrolysis product (3-chloropropyl)methylsilanediol.

72 h NOEC: 57 mg/l S. subspicatus (read-across from CAS 13501-76-3), or 42 mg/l when expressed in terms of the silanol hydrolysis product (3-chloropropyl)methylsilanediol.

Key value for chemical safety assessment

EC50 for freshwater algae:

321 mg/L

EC10 or NOEC for freshwater algae:

42 mg/L

Additional information

There are no reliable data for the effects of the registered substance on growth of aquatic algae. A 72-hour EC₅₀ value of 437 mg/L and NOEC of approximately 57 mg/L have been determined for the effects of the structurally analagous substance (3-chloropropyl)diethoxtmethylsilane (13501-76-3) on growth rate of Scenedesmus subspicatus. The results are interpreted with reference to nominal concentrations of the test substance. However it is likely that the test organisms were predominantly exposed to the hydrolysis products of the substance during the study, and not the parent compound. This is because the substance hydrolyses in water, as indicated by the DOC concentrations in the stock solution. The test media preparation included a stirring period of 18 h and the exposure regime was static.

The results may be expressed in terms of concentration of the hydrolysis product, (3-chloropropyl)methylsilanediol, by applying a molecular weight correction: (MW of silanol = 154.67 / MW of parent = 210.78) * EC₅₀ = 437 mg/l and NOEC = 57 mg/l = EC₅₀ 321 mg/l and NOEC 42 mg/l as (3-chloropropyl)methylsilanediol.