Multimedia Transport Modeling for ChemicalDynamics at Watershed Scale

摘要

A GIS-integrated multimedia model (GIM3) was presented for analyzing the dynamicdistribution of chemicals in the multimedia environmental system. In this model, multimediatransport and exposure assessment were incorporated in a GIS-based framework, whichsupported the spatial characterization and the simulations of meteorological and hydrologicprocesses at watershed-airshed scale. A set of equations are established to formulate the intermediamass transport across uniform (air, water, vegetation) and nonuniform (soil and sediment)environmental compartments. For the approach to be of practical use, the transport and reactioncoefficients are estimated by theoretical and empirical methods adopted from literatures. Thecurrent model has a more detailed environmental description than previous multimedia modesin order to give a more accurate representation of environmental fate of chemicals. Suchdetailed environmental descriptions are particularly valuable when chemical heterogeneity isexpected within environmental media as occurs with more relative chemicals or local scalesimulations. Information obtained from such analysis, which includes chemical concentration