Use of physicochemical parameters to assess the environmental fate of organic pollutants: The fugacity model

The use of Mackay fugacity is introduced to determine the partition of organic pollutants in multiphase environmental systems. The fugacity, f, of a substance is defined as its tendency to escape from a given phase and has the units of pressure. Therefore, the fugacity of a gas is closely related to the partial pressure and the fugacity of a pure solid or liquid is given by its equilibrium vapor pressure at specified temperature. In addition, an environmental system constitutes different phases such as air, water, soil, sediment, suspended solids in a fluid, biota and so forth. To estimate the distribution of a pollutant among the different phases, the first step is to evaluate the fugacity capacity for the pollutant in the different phases. This model allows the use of different partition constants in an easy way, to determine the distribution of a chemical between different phases in equilibrium of an environmental system. Moreover, other complex calculations can be performed using other levels of increasing complexity.