Dichloro(methyl)(phenyl)silane

Endpoint summary

Additional information

Reliable short-term toxicity to aquatic invertebrates data are available with the registration substance dichloro(methyl)(phenyl)silane (CAS 149-74-6).

The relevant short-term value is:

Daphnia:

Key EC₅₀ (48 h): >100 mg/l nominal concentration (Wacker 2003). This EC₅₀ is equivalent to >81 mg/l when expressed in terms of concentration of the silanol hydrolysis product methylphenylsilanediol.

 

No other data are available for the registration substance, dichloro(methyl)(phenyl)silane (CAS 149-74-6). However, data are available with the structurally related substances, dichloro(3-chloropropyl)(methyl)silane (CAS 7787-93-1), 3-chloropropyl(diethoxy)methylsilane (CAS 13501-76-3) and trichloro(phenyl)silane (CAS 98-13-5). All substances hydrolyse to structurally similar silanol containing hydrolysis products (see the ecotoxicological discussion for justification of read-across).

The relevant short-term values are:

Fish:

WoE LC₅₀ (96 h): >107 mg/l nominal concentration, Cyprinus carpio, read-across from dichloro(3-chloropropyl)methylsilane (CAS 7787-93-1) (Evonik 1997). This LC₅₀ is equivalent to >86 mg/l when expressed in terms of concentration of the silanol hydrolysis product (3-chloropropyl)(methyl)silanediol.

WoE LC₅₀ (96 h): 574 mg/l, Danio rerio, read-across from (3-chloropropyl)diethoxymethylsilane (CAS 13501-76-3) expressed in terms of measured concentrations of Dissolved Organic Carbon (DOC) (Evonik 1995). It is very likely that the test organisms were exposed to the hydrolysis products (3-chloropropyl)(methyl)silanediol and ethanol.

WoE LC₅₀ (96 h): >100 mg/l nominal concentration, Oncorhynchus mykiss, read-across from trichloro(phenyl)silane (CAS 98-13-5) (Springborn Smithers 2009). This LC₅₀ is equivalent to >74 mg/l when expressed in terms of concentration of the silanol hydrolysis product phenylsilanetriol.

 

 

Algae:

WoE ErC₅₀ (72 h): 437 mg/l, ErC₁₀ 137 mg/l and NOEC 57 mg/l nominal concentration, Desmodesmus subspicatus, read-across from (3-chloropropyl)diethoxymethylsilane (CAS 13501-76-3) (Evonik 1994). The results are equivalent to EC₅₀ 321 mg/l and EC₁₀ 101 mg/l when expressed in terms of concentration of the silanol hydrolysis product (3-chloropropyl)(methyl)silanediol.

WoE ErC₅₀ (72 h): >100 mg/l and ≥100 mg/l (nominal concentration), Oncorhynchus mykiss, read-across from trichloro(phenyl)silane (CAS 98-13-5) (Springborn Smithers 2009). The ErC₅₀ and NOEC are equivalent to >74 mg/l and ≥74 mg/l, respectively, when expressed in terms of concentration of the silanol hydrolysis product phenylsilanetriol.

 

The rapid or moderate hydrolysis rates of the registration and read-across substances, and test media preparation methods, mean it is likely that the test organisms in each test were exposed primarily to the hydrolysis products of the tested substances.

 

Data with trichloro(phenyl)silane (CAS 98-13-5) have been included because the substance is a structural analogue of the registration substance and as evidence of the low toxicity of the phenyl group.

 

An activated sludge respiration inhibition study (OECD 209) is available for trichloro(phenyl)silane (CAS 98-13-5). This data is read-across to the submission substance. A 3-hour EC₅₀ value of >1000 mg/l was determined.