CoZMo-POP 2 – A fugacity-based dynamic multi-compartmental mass balance model of the fate of persistent organic pollutants

CoZMo-POP 2, a dynamic multimedia fate and transport model (MFTM) for describing the long-term fate of persistent organic pollutants (POPs) in a coastal environment or the drainage basin of a large lake is described. The modelled environment, consisting of up to 19 compartments, includes the forest, soils and fresh water bodies of the drainage basin, and a variable number of sequentially arranged marine water units, representing estuarine, coastal, open and deep water environments. Two sediment compartments in each water basin allow to account for the possibility of the simultaneous occurrence of eroding and accumulating bottoms in a water basin. As the movement of POPs in the environment is closely associated with the movement of air, water and organic matter, the model constructs complete steady state mass budgets for air, water and particulate organic carbon (POC) between the model compartments from the environmental parameters supplied by the user. This assures that these input parameters, which can be stored in a database, are all mutually compatible and internally consistent. The CoZMo-POP 2 model takes into account seasonably variable wind speeds, temperatures, canopy developments and OH radical concentrations, and allows for the definition of time-variant emission scenarios. CoZMo-POP 2 is a flexible, dynamic MFTM that can be used for detailed investigation of a particular fate process using a generic environmental scenario, as well as for simulations of the behaviour of a particular POP in a particular environment. All of the model equations, which are expressed in fugacity notation, are provided.