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Ecotoxicological information

Ecotoxicological Summary

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Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.2 mg/L
Assessment factor:
50
Extrapolation method:
assessment factor
PNEC freshwater (intermittent releases):
1.7 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.02 mg/L
Assessment factor:
500
Extrapolation method:
assessment factor

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
1 mg/L
Assessment factor:
100
Extrapolation method:
assessment factor

Sediment (freshwater)

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

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
0.074 mg/kg sediment dw
Assessment factor:
10
Extrapolation method:
equilibrium partitioning method

Hazard for air

Hazard for terrestrial organisms

Soil

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

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Short-term ecotoxicity data for three trophic levels are available for the substance or can be read-across from trimethoxyvinylsilane. This substance hydrolyses rapidly to vinylsilanetriol, which is a close structural analogue of the hydrolysis product of the triacetoxyethylsilane, ethylsilanetriol. The test organisms in each test with trimethoxyvinylsilane were primarily exposed to the hydrolysis product vinylsilanetriol. The rapid hydrolysis of triacetoxyethylsilane means it is appropriate to calculate a PNECfreshwater on the basis of data for the silanol hydrolysis product. The relevant short-term values are:

Fish:LC50 (96 h): 251 mg/l

Daphnia:EC50 (48 h): 169 mg/l

Algae:EC50 (7 d): 210 mg/l

In addition, a 21-day NOEC value of ≥100 mg/L has been determined for the effects of trichloro(ethyl)silane on survival and reproduction of Daphnia magna when expressed in terms of nominal concentrations. When expressed in terms of mean measured TOC concentration in the test medium the NOEC was ≥10 mg/L. A NOEC of 25 mg/l was determined in the algal test for trimethoxyvinylsilane. It is again likely that the test organisms were primarily exposed to the hydrolysis products of the substance.

The standard approach to PNEC calculation when long-term data are available for two trophic levels, including that which was found to be most sensitive in the short term tests, is to apply an assessment factor of 50 to the NOEC.

Therefore, PNECaquatic is10/50 =≥0.2mg/l.

Conclusion on classification

Triacetoxyethylsilanehydrolyses very rapidly and the silanol hydrolysis product is not readily biodegradable.

The substance is not classified for the environment in the EU according to the Regulation (EC) No. 1272/2008 because reliable data for the substance and for suitable read-across substances present EC/LC50 >100 mg/l and long-term NOEC values are >1 mg/l.