Proof-of-Concept Application of Tier 2 Modeling Approach within the Training Range Environmental Evaluation And Characterization System.

摘要

The Training Range Environmental Evaluation and Characterization System (TREECS) is being developed for the Army to forecast the fate of and risk from munitions constituents (MCs), such as high explosives (HE), within and transported from firing/training ranges to surface water and groundwater. The overall objective is to provide environmental specialists with tools to assess the potential for migration of MCs into surface water and groundwater systems and to assess range management strategies to protect human and environmental health. Tier 1 consists of screening-level methods that assume highly conservative, steady-state MC loading and fate. Tier 1 requires minimal data input and can be easily and quickly applied by environmental staff. If MC concentrations predicted with Tier 1 exceed protective health benchmarks at receptor locations, then further evaluation with Tier 2 is recommended to obtain more definitive results. Tier 2 provides time-varying analyses since it does not make the highly conservative assumptions of steady-state (time- invariant) conditions with no MC loss or degradation as used for Tier 1. Tier 2 solves mass balance equations for both solid and non-solid phase MC with dissolution. MC residue loadings to the range soil can vary from year to year based on munitions use; thus, media concentrations computed with Tier 2 should be closer to those expected under actual conditions. Media concentrations will also reflect time phasing associated with time-varying MC loading conditions and transport arrival times, which can be greatly extended for the vadose zone and groundwater. Having time as a dimension in the analysis provides a powerful tool for examining range management strategies to promote attenuation of media concentrations. This report describes the proof-of-concept application of the prototype TREECS Tier 2 modeling approach and provides recommendations for final implementation and use of those methods.