The goal of the DARPA "Dog's Nose" program is to develop a sensor capable of detecting explosives contained in all buried landmines. In support of the DARPA program, the purpose of the Explosives Fate and Transport (EF&T) experiments is to define in detail the accessible trace chemical signature produced by the explosives contained in buried landmines. We intend to determine the partitioning (soil, air, water), composition, and quantity of explosive related chemicals (ERC) which emanate from different kinds of landmines (predominantly plastic-cased with TNT as the main charge) buried in multiple soil types and exposed to various climatic events. We are also developing a computer model that will enable us to predict the composition and quantity of ERC under a much wider range of environmental conditions than we are able to test experimentally.In our systematic quest to define the signature of a buried mine we have divided our efforts into the following categories:1 . Chemical analysis of the main explosive charge from several sources of TNT and the equilibrium vapor associated with TNT from these sources. 2. The amount and composition of ERC that are found on the exterior of landmines. 3. Determination of the rate at which ERC permeate the casing materials of both plastic and metallic landmines. 4. The effect that different soils have on the transport and fate of ERC as they move through the soil/pore matrix to the surface.5. The effect of environmental factors on ERC, i.e., climate, time since burial, depth of burial, soil properties, sunlight, near surface air movement, and vegetation.

The fate and transport of chemical signature molecules that emanate from buried landmines is strongly influenced by physical chemical properties and by environmental conditions of the specific chemical compounds. Published data have been evaluated as the input parameters that are used in the simulation of the fate and transpon processes. A one-dimensional model developed for screening agricultural pesticides was modified and used to simulate the appearance of a surface flux above a buried landmine, estimate the subsurface total concentration. and show the phase specific concentrations at the ground surface. The physical chemical properties of T N T cause a majority of the mass released to the soil system to be bound to the solid phase soil particles. The majority of the transport occurs in the liquid phase with diffusion and evaporation driven advection of soil water as the primary mechanisms for the flux to the ground surface. The simulations provided herein should only be used for initial conceptual designs of chemical pre-concentration subsystems or complete detection systems, The physical processes modeled required necessary simplifying assumptions to allow for analytical solutions. Emerging numerical simulation tools will soon be available that should provide more realistic estimates that can be used to predict the success of landmine chemical detection surveys based on knowledge of the chemical and soil properties, and environmental conditions where the mines are buried. Additional measurements of the chemical properties in soils are also needed before a fully predictive approach can be confidently applied.

Military test and training ranges operate with live fire engagements to provide realism important to the maintenance of key tactical skills. Ordnance detonations during these operations typically produce minute residues of parent explosive chemical compounds. Occasional low order detonations also disperse solid phase energetic material onto the surface soil. These detonation remnants are implicated in chemical contamination impacts to groundwater on a limited set of ranges where environmental characterization projects have occurred. Key questions arise regarding how these residues and the environmental conditions (e.g. weather and geostratigraphy) contribute to groundwater pollution impacts. This report documents interim results of experimental work evaluating mass transfer processes from solid phase energetics to soil pore water. The experimental work is used as a basis to formulate a mass transfer numerical model, which has been incorporated into the porous media simulation code T2TNT. Experimental work to date with Composition B explosive has shown that column tests typically produce effluents near the temperature dependent solubility limits for RDX and TNT. The influence of water flow rate, temperature, porous media saturation and mass loading is documented. The mass transfer model formulation uses a mass transfer coefficient and surface area function and shows good agreement with the experimental data. Continued experimental work is necessary to evaluate solid phase particle size and 2-dimensional effects, and actual low order detonation debris. Simulation model improvements will continue leading to a capability to complete screening assessments of the impacts of military range operations on groundwater quality. 4

Issued by Sandia National Laboratories, operated for the United States Department of Energy by Sandia Corporation. NOTICE This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government, nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, make any warranty, express or implied, or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represent that its use would not infringe privately owned rights. Reference herein to any spedfc commercial product, proccss, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government, any agency thereof, or any of their contractors or subcontractors. The views and opinions expressed herein do not necessarily state or reflect those of the United States Government, any agency thereof, or any of their contractors.

High order detonation of military ordnance can deposit trace residues of explosive chemical constituents on or in surface soil. Low order detonations can disperse distinct solid phase energetic material as fme particulates to large masses. Mass transfer of solid phase energetics to soil pore water is being evaluated to assess environmental impacts to soil and groundwater. This report documents measurements of solubility and dissolution kinetics of Composition B (60% RDW400? TNT) in water. The solubility of RDX and TNT were determined at environmentally relevant temppatures (7 to 40 "C) in both deionized and tap water. Demilitarized Composition B explosive was cracked and sieved to produce discrete size fractions simulating low order detonation debris for use in dissolution kinetics experiments. The kinetics of dissolution were determined in an unconstrained dissolution process where the solution concentrations were below solubility maxima. Dissolution rates were derived from solution concentration and calculated particle surface area changes over time.