A Generalized, Mass-Conserving Multimedia Transport and Transformation Model: Development of Transfer Factors. S. Guha, IT Corporation, 312 Directors Drive, Knoxville, TN 37923; T. E. McKone and D. H. Bennett, Lawrence Berkeley National Laboratory, One Cyclotron Road, 90-3058, Berkeley, CA 94720; and B. F. Lyon, Oak Ridge National Laboratory, MS-6480, Oak Ridge, TN 37830
This paper describes the development of the compartmentalized mass transfer (CMT) model, which is used to estimate transfer of pollutants between various compartments of a bounded system that includes biotic and non-biotic elements. This model is being developed to meet Total Risk Integrated Models (TRIM) requirement for complete mass balance in a simulated ecosystem. To account for mass-balance, we define a set of compartments collectively accounting for all potential locations of mass within a bounded ecosystem and having sources and sinks outside the bounded system. Each compartment has an address that is indexed according to its spatial location, "domain" type, and chemical species. A system of linked differential equations describing pollutant mass transfer rates between pairs of addresses is at the heart of this model. The product of a transfer factor and pollutant mass in a given compartment address yields a total mass transfer rate for that pathway from that compartment address All linkages between address elements are simultaneously analyzed and transfer factors are estimated to determine the redistribution among compartment addresses over a specific time interval (t, t+dt). The solution of the system of linked differential equations yields the mass inventory at a the text time step, t+dt. To perform calculations, the model requires the distribution of mass among cells at initial time to, a listing of all potential address linkages and a library of algorithms for all domain-based exchanges. The features that make the CMT model unique are its system of linked differential equations across all locations, environmental domains, and chemical species and the estimation of transfer factors between addresses based on a library of algorithms. These features provide flexibility to an analyst in defining the complexity of a simulation.
Work supported by the U.S. EPA under Contract IAG DW89937232-01.