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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

Hazard assessment conclusion:
no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Conclusion on classification

CLASSIFICATION RELATED KEY INFORMATION

The registered (parent) substance ethoxy(trimethyl)silane (CAS 1825-62-3) hydrolyses rapidly in contact with water under environmentally relevant conditions (DT50 = 2.2 min at 25 °C and pH 7, EU Method C.7). Therefore, the environmental hazard and risk assessment is based on the silanol hydrolysis product, i.e. trimethylsilanol. The other, alcohol hydrolysis product, ethanol, is not expected to affect the environmental hazard profile of the parent substance (OECD SIDS, 2004).

Abiotic degradation - Hydrolysis

DT50 = 2.2 min at 25 °C and pH7 (EU Method C.7)

 

Biodegradation in water

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

 

Bioaccumulation

Ethoxytrimethylsilane (parent): Log Kow = 3.7 (QSAR)

Trimethylsilanol (hydrolysis product): Log Kow = 1.19 (measured)

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

 

Aquatic acute toxicity:

Fish

LC50 (96 h) = 271 mg/L (measured geometric mean, OECD 203; RA CAS No. 1066-40-6)

Aquatic invertebrates

EC50 (48 h) = 124 mg/L (measured, OECD 202; RA CAS No. 1066-40-6)

 

Algae

ErC50 (72 h) > 684 mg/L (measured geometric mean, OECD 201; RA CAS No. 1066-40-6)

  

Chronic aquatic toxicity

Algae

NOErC (72 h) = 44 mg/L (measured geometric mean, OECD 201; RA CAS No. 1066-40-6)

 

Classification according to CLP

Ethoxytrimethylsilane (CAS 1825-62-3) hydrolyses rapidly in water (DT50 = 2.2 min at pH 7 and 25 °C), to the hydrolysis products trimethylsilanol and ethanol. The silanol hydrolysis product is not considered readily biodegradable, while the second hydrolysis product ethanol is readily biodegradable (OECD SIDS, 2004). Acute aquatic toxicity data are available for all three trophic levels for the silanol hydrolysis product. Acute aquatic toxicity was recorded in excess of 100 mg/L and a NOEC (72 h) of 44 mg/L was derived in the study with aquatic algae. On this basis, ethoxytrimethylsilane is not classified as hazardous to the environment according to the consolidated version of Regulation (EC) No 1272/2008 (CLP) and all further amendments (ATPs).