Registration Dossier

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.234 mg/L
Assessment factor:
500
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
2.34 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.023 mg/L
Assessment factor:
50
Extrapolation method:
assessment factor
PNEC marine water (intermittent releases):
0.234 mg/L

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
10 mg/L
Assessment factor:
10
Extrapolation method:
assessment factor

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
0.995 mg/kg sediment dw
Extrapolation method:
equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.1 mg/kg sediment dw
Extrapolation method:
equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
PNEC soil
PNEC value:
0.062 mg/kg soil dw
Extrapolation method:
equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Conclusion on classification

Classification related key information

Hydrolysis:

Diethoxy(dimethyl)silane CAS 78-62-6: hydrolysis half-life = 5.5 h at 20-25 °C and pH7 (QSAR)

 

Biodegradation:

Not readily biodegradable: 0% (inorganic C-analysis) in 28 d (OECD 310) based on read-across from CAS 1066-40-6

 

Bioaccumulation:

Diethoxy(dimethyl)silane (parent): Log Kow = 3 (QSAR)

Dimethylsilanediol (hydrolysis product): Log Kow = -0.4 (QSAR)

Ethanol (hydrolysis product): Log Kow = - 0.3 (measured)

 

Acute toxicity:

to fish: LC50 (96 h) > 126 mg/L (measured arithm. mean, OECD 203)

to aquatic invertebrates: EC50 (48 h) > 117 mg/L (measured arithm. mean, OECD 202)

to algae: ErC50 (72 h) > 118 mg/L (measured arithm. mean, OECD 201)

 

Chronic toxicity:

to algae: NOErC (72 h) ≥ 118 mg/L (measured arithm. mean, OECD 201)

 

Conclusion on classification:

Diethoxy(dimethyl)silane (CAS 78-62-6) hydrolyses rapidly in water (estimated DT50 5.5 h at pH7), to dimethylsilanediol and ethanol. The silanol hydrolysis product is not readily biodegradable. Acute toxicity data are available for all three trophic levels from the silanol hydrolysis product. No toxicity was observed in any trophic level up to the highest tested concentration of 126 mg/L. On this basis, Diethoxy(dimethyl)silane is not classified as hazardous to the environment according to Regulation (EC) No 1272/2008 (CLP).