Chlorotrifluoroethylene

Toxicity to aquatic algae and cyanobacteria

Description of key information

In accordance with column 2 of REACH (REGULATION (EC) No 1907/2006) Annex VII the study on toxicity to aquatic algae and cyanobacteria (required in section 9.1.2) does not need to be conducted as there are mitigating factors indicating that aquatic toxicity is unlikely to occur:
1. CTFE is expected to rapidly partition to atmosphere.
2. CTFE is not expected to partition to water. 
The explanations supporting the above mitigating factors are the following:
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 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 solubilityand a moderate water solubility (the water solubility value of 380 mg/l  has been evaluated in a closed system with the atmosphere saturated of CTFE hence it represents an overestimation of the actual water solubility of CTFE in the natural system), CTFE is expected to primarily and rapidly partition to the atmosphere.
The EQC Fugacity III Model 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. 

Additional information

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) and a moderate water solubility (the water solubility value of 380 mg/l has been evaluated in a closed system with the atmosphere saturated of CTFE hence it represents an overestimation of the actual water solubility of CTFE in the natural system).

The Henry’s Law constant of CTFE was calculated to be 31.500 Pa m3/mol (HENRYWIN v3.20, EPI Suite v4.0), suggesting that the substance is expected to rapidly volatilise from water to the air in fact 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 the properties of CTFE it is expected that the substance primarily and rapidly partition to the atmosphere.

In addition the EQC Fugacity III Model confirms that the whole amount of 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 air, because CTFE is a volatile gas at ambient conditions.

Hence, due to the gaseous nature of the substance and its partition to the atmosphere, as well as the consequent difficulty to appropriately test CTFE and provide meaningful results, no experimental aquatic toxicity data are reported. However, in order to evaluate theaquatic hazard profile of CTFE despite the fact that it is expected to rapidly partition to the atmosphere compartment, the results of the ECOSAR model ( v.1.00, EPI Suite v 4.0) may be applied.

The ECOSAR estimation for acute toxicity for algae is: 96h EC50 1349.048 mg/L, however due to the limited dataset of substances for this class of chemicals the result is not considered reliable.