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Atmospheric conditions - diurnal and seasonal Phelan
Precipitation and runoff
Thermal radiation - solar, sky, ground
Plant growth and transpiration
Wind
Ground surface
Vapor-Solid
Partitioning
Soil
particle
Liquid-Solid sorption
Vapor-Liquid
Diffusion Partitioning Precipitation Diffusion Partitioning

Evaporation/ Evapotranspiration Solid phase
Condensation Transformation

Microbial
and/or Loss
degradation/
Plant root
Vapor phase
Liquid phase
uptake
Landmine
Figure 21.1. Complex interdependencies affecting landmine chemical signatures in soil

to location-specific weather impacts on laboratory determined landmine chemical
emissions to provide a comprehensive time-series analysis of the changes in explo-
sive vapor emanations at the ground surface (Webb and Phelan, 2003). Data-model
comparisons between simulation results and landmine soil residue chemical data
showed good correlation and affirmed that this approach can provide great insight
into the art of landmine detection (Phelan and Webb, 2003).
A number of soil physics based simulation models have been used to evaluate
landmine chemical vapor transport in soils. The models evolved from simple screen-
ing methods to more complex numerical approaches as insight was gained in the
phenomenon involved.
The Behavior Assessment Model (BAM) (Jury et al., 1983, 1984a, b, c), which
was later modified to become the Buried Chemical Model (BCM) (Jury et al., 1990)
uses a one-dimensional screening model to compare the pollution potential of various
agricultural chemicals. The BAM and BCM models were very useful in categorizing
the relative mobility, volatility and persistence of the landmine signature chemicals
TNT, DNT and DNB in relation to other well-characterized agricultural chemicals.
These models only require a simple set of input parameters: soil-water partitioning
coefficient (K d ), soil-air partitioning coefficient (Henry’s constant, K H ), diffusion
coefficient in air (D G ), and the bio-chemical half-life (T 1/2 ).