Dynamic distribution of nitrate in Lower Connecticut River Basin: A multimedia screening-level modeling approach

Abstract

A GIS-integrated spatial-compartmental modeling approach was presented for analyzing the dynamic transport and distribution of chemicals in the multimedia environment system. The intermedia mass transport processes were incorporated into a GIS-based modeling framework, which supported the multi-media analysis and exposure assessment by simulating the meteorological and hydrologic processes at watershed-airshed scale. In order to simplify the inter-phase transfers and allow for scenario analysis, the modeling framework adopted a dynamic fugacity approach to formulate the inter-media mass transport across uniform (air, water, vegetation) and nonuniform (soil and sediment) environmental compartments. For the approach to be of practical use, parameter input could be minimized by theoretical and empirical description of inter-media mass transport processes and estimation methods for associated biochemical transformation parameters. The model was applied to simulate dynamic nitrate distribution in the lower Connecticut River basin. Input parameters included a geographic description of each environmental compartments, meteorological data, emission rates, and chemical prosperities. The numerical model primarily provided a screeninglevel assessment of the compartmental distractions and inter-media transport rates of nitrate in the basin. The predicted concentrations were comparable with the data from measurements and outputs from other models. These results suggest that this multimedia modeling approach is appropriate for perform a dynamic screening-level simulation of the transport and distribution of chemicals at watershed-airshed scale.