Institution: | Department of Geography University of Toronto 100 St. George St., Toronto, Ontairo, Canada M5S 1A1 Institute for Environmental Studies University of Toronto, Toronto, Ontario, Canada M5S 1A4 Environmental and Resource Studies Program Trent University, Peterborough, Ontario, Canada K9J 7B8 |
Abstract: | The fugacity or aquivalence approach to environmental modelling is extended to treat chemicals which may be present as several inter-converting species in a multi-media environment. Species-specific and total Z values are defined expressing the capacity of each phase for each species of chemical. Similarly, species-specific and total D values are defined to quantify transport and transformation rates. Fugacity or aquivalence is used as the criterion for partitioning behaviour or physical equilibrium. By defining species proportions on an aquivalence or fugacity fraction basis, the equations for multiple species can be consolidated into a single “pseudo single-component” mass balance equation. Steady-state multi-species, multi-compartment mass balance models can be assembled for such systems and solved in various ways to give mass balances and distributions for all species amounts, concentrations, fluxes and species conversion rates. Examples are presented for a hypothetical substance present as three species in a system under equilibrium and non-equilibrium, steady-state conditions. |