Dimethyl ether-boron trifluoride

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

In contact with water, dimethyl ether - boron trifluoride rapidly decomposes to form dimethyl ether and boron trifluoride dihydrate. The PBT assessment was consequently based on the properties of the hydrolysis products. Both decomposition products do not fulfil the PBT/vPvB criteria.

- Boron trifluoride and its breakdown products are not expected to bioaccumulate in fish/earthworm tissues due to their high solubility and octanol-water partition coefficients which are quite low. Moreover due to the expected very short half-life in aqueous media (hydrolysis), boron trifluoride is not expected to be persistent in aquatic and terrestrial media. Considering all those elements one can safely conclude that secondary poisoning is not expected as birds and terrestrial top predators will not be exposed to boron trifluoride and its breakdown products via food consumption.

- Boron trifluoride and its breakdown products fulfil the Toxic criterion: concerning the aquatic compartment EC50 or        LC50 > 0.1 mg/L and NOEC for mammals > 30 mg/kg food. However, boron trifluoride is classified as R48.

In conclusion, boron trifluoride does not fulfil the PBT/vPvB criteria. Concerning dimethyl ether, the substance is identified as being potentially persistent as stipulated in the ECHA Guidance on information requirements and chemical safety assessment, but not bioaccumulative (due to LogKow < 3.0). There is no other evidence of chronic toxicity, as identified by the classifications T, R48 or Xn, R48 according to Directive 67/548/EEC or specific target organ toxicity after repeated exposure (STOT RE category 1 or 2) according to Regulation EC No 1272/2008. In conclusion dimethyl ether does not fulfil the PBT/vPvB criteria.

Likely routes of exposure:

Because the substance does not fulfil the PBT and vPvB criteria, no emission characterisation is performed.