The Contaminant Transport, Transformation, and Fate Sub-Model for Predicting the Site-Specific Behavior of Distributed Sources (Munitions Constituents) on U.S. Army Training and Testing Ranges

摘要

Contaminant Transport, Transformation and Fate (CTT&F) sub-model was developed for coupling with existing watershed hydrological modeling systems to predict the site-specific behavior of distributed sources (munitions constituents) on U.S. Army training and testing ranges. Physical transport and transformation processes across the land surface are simulated using distributed approach and routed through channels to the watershed outlet. The CTT&F sub-model includes the ability to represent explosive contaminant processes at the watershed scale including: partitioning of contaminants to solid particles, freely dissolved, dissolved organic carbon (DOC) bound dissolved, and sediment sorbed particulates, erosion and settling of particle associated contaminants, diffusive and mixing exchanges across the water column and upper soil (sediment) interface. CTT&F has the capability to simulate biodegradation, hydrolysis, oxidation, photolysis, volatilization, dissolution, and other transformation processes. To demonstrate model capabilities, CTT&F was coupled with a Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model, then tested and validated to simulate RDX and TNT transport and transformation using two experimental plots. These experiments examined dissolution of solid contaminants into the dissolved phase and their subsequent transport to the plot outlet. Model results were in close agreement with measured data. Such model can be used to forecast the fate of munitions constituents within and transported from training ranges and to assess range management strategies to protect human and environmental health.