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Environmental fate & pathways

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Degradation

HCFC 123 is a stable molecule in water. Abiotic hydrolysis or phototransformation in water are not considered significant degradation pathways, due to the absence of hydrolysable groups and to the very high volatility of the molecule.

In the atmosphere, HCFC 123 is subject to hydroxyl radical-mediated photodegradation in the troposphere, resulting in a calculated global atmospheric lifetime ranging from 1.2 to 2.4 years.

Due to the absence of direct or indirect exposure to these compartments, the stability of HCFC 123 in soil and sediment is to be considered as not relevant.

HCFC 123 resulted not readily biodegradable under aerobic conditions, but a significant biodegradation was observed in one study under anaerobic conditions.

Bioaccumulation

In view of the low octanol-water partition coefficient (Log Kow = 2.17), HCFC 123 is not expected to bioaccumulate in the environment.

Environmental distribution

Due to the high Henry's Law Constant and to the predicted low adsorption potential, HCFC 123 is expected to distribute mainly in the atmospheric compartment following its emission into the environment.

The environmental distribution of HFC-125 was estimated be means of the Fugacity Model Level III (2002), under the assumption that 100% release occurs in air. The Level III model’s results indicated that HFC-125 would partition mainly into the air compartment (99.8%) and about 0.12% and 0.04% in water and soil compartments, respectively.

Volatilisation of HCFC 123 from the water compartment was estimated by means of EPISUITE v4.00. The model estimated a removal half life of 1.29 hours and 117.8 hours in rivers and lakes, respectively, indicating a low persistency of the substance in the water compartment.