Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Stability

A photochemical trajectory model has calculated a photochemical ozone creation potential (POCP) of zero for the test substance (HFC-143a) demonstrating a negligible contribution to photochemical ozone production (Hayman and Derwent, 1997).

Several national and international reports and studies are available that provide global warming potential (GWP) values for the test substance (generally reported as HFC-143a). Transport modelling has predicted an atmospheric lifetime of 1,1,1,-trifluoroethane to be 47.2 years (Naik et al, 2000) compared with 53.5 years as previously reported by Grainer et al (1999). In addition, the IPCC’s Fourth Assessment Report predicted an atmospheric lifetime of 52 years.

The substance is non-ozone depleting but is a global warming substance. The substance is a gas and expected to fully partition to the air compartment with an estimated half-life in air of up to 53.5 years, using the most conservative estimate. Releases of HFCs are unlikely to cause damage at a local level, but they do have a global environmental effect as greenhouse gases contribute to global warming. Although their global warming potential is high (up to 3800 times for HFC-143a over a 100 year horizon), the relatively small amounts involved mean that they play a small role compared to other greenhouse gases.

 

Biodegradation

Based on calculations using EpiWin software (US EPA, 2008) 1,1,1,-trifluoroethane is predicted to have a very short residence time in aqueous bodies. It is also predicted that it will not biodegrade, but will volatize into the atmosphere.

 

Bioaccumulation

The substance is not likely to bioaccumulate through the ecosystem. The substance has a predicted Log Kow of <1.35 (at 20 degrees C) and high vapour pressure at ambient conditions indicating a low potential for bioaccumulation.

 

Transport and Distribution

A Henry's Law constant of 11.2 kPa m3/mol has been reported in the Physical Properties Handbook.

The substance is only released to the atmosphere during manufacture and use. Fugacity-based modelling (US EPA, 2008) predicts that upon release to the air over 99.9% will remain in the air and less than 0.1% will partition into the combined soil and water compartments. Therefore, due to its high Henry's Law constant of 11.2 kPa m3/mol and low adsorption potential, it will partition mainly to the atmosphere following emission to the environment.

Additional information

No additional information