Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The test substance is a gas under all environmental conditions and only slightly soluble in water. It has a high vapour pressure and therefore environmental releases will result in virtually all of the substance compartmentalising into the atmosphere. Any potential atmospheric deposition to land and water would result in rapid redistribution from soil and water due to its volatility and low sorption to soil. This is supported by a Level I fugacity model (Mackay, 2003) which is used to calculate the theoretical distribution of VDF between four environmental compartments (air, water, soil, sediment) at equilibrium in a unit world. The model calculates that 100% of VDF partitions to the atmosphere and a very small portion partitions to water (0.03%).

VDF is not expected to hydrolyse under normal environmental conditions.

VDF undergoes reactions with hydroxyl radicals in the atmosphere. Using a degradation rate constant of 2.27E-12 cm3/molecule/ses the half life of VDF AOPWIN™ vv1.92a (U.S. EPA, 2008), based on a 12-hr day with an OH radical concentration of 1.5E6 OH/cm3, is 4.7 days (see Annexes 2 and 3 for the QMRF and QPRF).

No data on biodegradability is available. Information from related gaseous materials (pentafluoroethane and vinylidine chloride) generally showed ≤ 5% degradation (SIDS, 2005 and NITE, 1992) Based on these analogous substances, VDF is not expected to be readily biodegradable (see Annex 4 for the Reporting Format).

Only a calculated organic carbon-water partitioning coefficient (Koc) is available from KOCWINv2.00 (U.S. EPA,, 2008). The calculated Koc is estimated to be 11.9 L/kg (log value is 1.08)(see Annexes 5 and 6 for the QMRF and QPRF).

VDF has an experimental log Kow of 1.24. This value indicates that possible bioaccumulation in the food chain is not significant. Based on its limited water solubility and the substance being a gas, it can be concluded that VDF will volatilize rapidly, and therefore partition nearly exclusively to air (>99%) and will not remain in the water. Significant contact with the organisms in the food chain can therefore considered to be negligible. This is supported by the BCF of 3.06 L/kg calculated with BCFBAFv3.00 (U.S. EPA, 2008)(see Annexes 7 and 8 for the QMRF and QPRF).