Effects of environmental parameters on the chemical signature of landmines

Abstract

The presence of buried landmines is an environmental problem in many parts of the world; strategies to detect and remove landmines are being developed; one of these strategies is the developing of chemical based sensors. Even when most landmines cases are made from plastic, small amounts of explosive may diffuse through the case (or through cracks), enter the soil and migrate to the surface. The spatial and temporal concentration distribution of chemicals released from a landmine at the soil surface is influenced by: the type of soil, environmental factors, water and gaseous phase mobility, molecular and mechanical diffusion, adsorption characteristics, water content, and compaction. In this work we measure the concentration of chemicals at the surface at different ambient conditions. Experiments are carried out using a series of soil tanks with controlled conditions such as: temperature, moisture content, relative humidity and radiation (UV and Visible). Gas Chromatography (GC-µECD) with Solid Phase Microextraction (SPME) and direct injection were used for the analysis of explosives. The results of the experiments will be used to provide validation for the simulation model describing the spectroscopic signature and its transport though soil. We have obtained the trends on the effect of the ambient conditions on the chemical signature. Of particular interest is the presence of several degradation compounds as time evolves.