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Classification & Labelling & PBT assessment

PBT assessment

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PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB
Justification:

PBT AND VPVB ASSESSMENT

PBT/vPvB screening criteria have been used to assess whether the substance fulfils the PBT or vPvB criteria.

 

Persistence Assessment

Triethoxy(methyl)silane is expected to hydrolyse rapidly in contact with water to methylsilanetriol and ethanol (half-life approximately 5.5 hours at 20-25°C and pH 7). Therefore, the substance is not persistent. The hydrolysis product ethanol is readily biodegradable and therefore also not persistent. A reliable ready biodegradation study is available for a structurally-analogous substance, which indicates that no significant biodegradation is expected for the silanol hydrolysis product.

 

Bioaccumulation Assessment

Triethoxy(methyl)silane is expected to hydrolyse rapidly in contact with water to methylsilanetriol and ethanol (half-life approximately 5.5 hours at 20-25°C and pH 7). Therefore, the parent substance will not bioaccumulate. The hydrolysis products methylsilanetriol and ethanol have low log Kow values (<3) and, therefore, are not likely to bioaccumulate either. Therefore, the substance does not meet the criteria for bioaccumulation; it is not B and not vB.

 

Toxicity Assessment

The substance is not considered as T for the environment, since the lowest measured EC50 for the substance was >500 mg/l and the lowest predicted EC50 for the hydrolysis product was 2115 mg/l. Both do not meet the screening criteria for T for the environment (EC/LC50 <0.1 mg/l). The substance is not classified for specific target organ toxicity, carcinogenicity, mutagenicity or reproductive and developmental toxicity in mammals. The criteria for “T” based on mammalian effects are therefore not met.

 

Summary and overall Conclusions on PBT or vPvB Properties

The substance is expected to hydrolyse very rapidly in the presence of water and therefore it does not meet the criteria for PBT or vPvB. The hydrolysis product may persist in the environment but does not meet the criteria for B and T and therefore the hydrolysis product should not be concluded as PBT or vPvB.