Chlorotrifluoroethylene

Endpoint summary

Additional information

Aquatic toxicity studies are not proposed by the registrant because direct or indirect exposure of the aquatic compartment is unlikely to occur as the substance is a volatile gas with a boiling point in the range of -26.2°C (The Beilstein database. Reference: Miller - 1951 ) to -26.8°C (The Beilstein database. Reference: Henne - 1948) which primarily and rapidly partition the atmosphere where it remains.

The above considerations have been deducted on the following basis:

The Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7a: Endpoint Specific Guidance, Appendix R.7.1-4 indicates that substances with a Henry's Law constant of around 1 hPa m3/mole will rapidly volatilise from water. On the basis of a Henry’s Law constant of 31,500 Pa m3/mol (HENRYWIN v3.20, EPISUITE v1.00), a vapour pressure of 612 kPa at 25°C (ISCS No. 0685, NIOSH) and a moderate water solubility, CTFE is expected to primarily and rapidly partition to the atmosphere.

The value of water solubility of 380 mg/l was experimentally determined in a completely sealed system with an atmosphere saturated with CTFE. Although the value of 380 mg/l itself reveals a moderate water solubility, it represents an overestimation of the actual water solubility of CTFE in the natural system since the experimental conditions did not represent the natural conditions.

The EQC Fugacity III Model (Version 2.02, The Canadian Centre for Environmental Modelling and Chemistry, May 2003)

confirms that all the CTFE released to air remains in this compartment. The model was run assuming emission only to air. In case of an accidental emission, CTFE is only released to atmosphere, because CTFE is a volatile gas at ambient conditions with a boiling point in the range of -26.2°C (The Beilstein database. Reference: Miller - 1951 ) to -26.8°C (The Beilstein database. Reference: Henne - 1948). Therefore, CTFE would not be expected to partition into water.

The specific properties of the substance, cited above, indicates the difficulty to properly test CTFE and provide meaningful results of its aquatic toxicity for this reason any experimental aquatic toxicity data are available. However, in order to evaluate the aquatic hazard profile of CTFE despite the fact, that it is expected to rapidly partition to the atmospheric compartment, the ECOSAR model may be applied.

All ECOSAR results are reported in the specific endpoints of this section however, the ECOSAR model cannot be considered reliable for the ECOSAR class of chemicals which CTFE is assigned to, since the results are either based on a very limited dataset of substances or, as for the most sensitive and critical group of the food chain the fish, the coefficient of determination R^2 is low.