Trifluoro(trifluoromethoxy)ethylene

Distribution modelling

Administrative data

Endpoint:

distribution modelling

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented and published methodology.

Data source

Reference

Reference Type:

other: Software calculation

Title:

EQC Model Version 3.13

Author:

The Canadian Environmental Modelling Centre (Trent University)

Year:

2021

Bibliographic source:

EQC (EQuilibrium Criterion) Model
https://www.trentu.ca/cemc/resources-and-models/eqc-equilibrium-criterion-model

Report date:

2021

Materials and methods

Model:

calculation according to Mackay, Level III

Calculation programme:

EQC Model Version 3.13

Release year:

2 021

Media:

other: soil - air - sediment -water

Test material

Test material information

Constituent 1

Reference substance name:

Trifluoro(trifluoromethoxy)ethylene

EC Number:

214-703-7

EC Name:

Trifluoro(trifluoromethoxy)ethylene

Cas Number:

1187-93-5

Molecular formula:

C3F6O

IUPAC Name:

1,1,2-trifluoro-2-(trifluoromethoxy)ethene

Test material form:

other: gas

Details on test material:

Test materials: the model is applied to the pure substance.

Study design

Test substance input data:

- Molar mass: 166 g/mol
- Data temperature: 25°C
- Water solubility: 31.5 g/m3
- Vapour pressure: 101325 Pa
- log Pow: 1.42
- Koc = 69.03
- Melting point: -155 °C

- Reaction half-life estimates for
- Air: 96 h
- Water: negligible ( a numerical value is needed for the model, therefore 100000 h is set)
- Soil: negligible ( a numerical value is needed for the model, therefore 100000 h is set)
- Sediment: negligible ( a numerical value is needed for the model, therefore 100000 h is set)

Results and discussion

Percent distribution in media

Air (%):

99.982

Water (%):

0.011

Soil (%):

0.006

Sediment (%):

0

Any other information on results incl. tables

The EQC Fugacity III Model clearly shows that all the PMVE released to atmosphere remains in this compartment. The rates of transfer to soil and water are reduced and only negligible amounts of the total emission distribute in these compartment and in sediments. Most of the reduced amount of PMVE that partitions into water then tends to comes back into air because of intermedia exchange and the rest is removed by advection. 

Applicant's summary and conclusion

Conclusions:

PMVE released to atmosphere remains substantially in this compartment. The rates of transfer to soil and water are reduced and only negligible amounts of the total emission distribute into these media and in sediments. Most of the reduced amount of PMVE that partitions into water then tends to comes back into air because of intermedia exchange and the rest is removed by advection.

Executive summary:

In order to understand the environmental fate of perfluoromethylvinylether (PMVE) the EQC Fugacity III Model has been applied (Version 3.13, The Canadian Centre for Environmental Modelling and Chemistry).

The EQuilibrium Criterion or EQC model is based on an evaluative multimedia model described by Mackay D. et al. The EQC model uses chemical-physical properties to quantify a chemical's behaviour in an evaluative environment. Three degrees of complexity are treated in the EQC: particularly, levels I and II assume thermodynamic equilibrium is achieved; level II also includes advective and reaction processes. Level III is a non-equilibrium, steady-state assessment of chemical fate in the environment.

The results of Level III model, which describes a situation more complex and realistic than previous models, are here presented.

The physico-chemical properties requested by this model are the following:

- water solubility: 31,5 mg/L

- vapour pressure: 101325 Pa (Vapour pressure of liquid PMVE at the boiling point)

- log Kow : 1.42

- melting point : -155.15°C

As input parameter a reaction half life in air of about 96 hours (4 days) has been entered too, while half-lives of 100000 h have been set for the other compartment.

Since in case of accidental emission PMVE is expected to be released only in air, an emission rate of 1000 kg/h has been assumed in this compartment, even if significanlty higher of the actual emissions into the environment.

To be noted that some of the reported input values are themselves conservative for the modellisation. For instance the reported water solubility value of 31.5 mg/L is itself not representative of the actual solubility of the substance in the natural environment as it was obtained with the use of laboratory conditions much more stringent (completely closed system with a PMVE saturated atmosphere) than the environmental ones. Also the entered vapor pressure value is considered conservative as it is the vapor pressure of the substance during the phase transition liquid to gas which occurr at -26°C while the data is entered as it was obtained at the temperature of 25°C, significantly undestimating the volatility of the substance in the model. Despite of this, the EQC Fugacity III Model clearly shows that essentially, all the PMVE released to atmosphere remains in this compartment. The rates of transfer to soil and water are reduced and only negligible amounts of the total emission distribute in these media and in sediments. Most of the reduced amount of PMVE that partitions into water then tends to comes back into air because of intermedia exchange and the rest is removed by advection.