Transport of Biological and Chemical Threat Agents in Soil

4 TRANSPORT OF BIOLOGICAL AND CHEMICAL THREAT AGENTS IN SOIL 

A biological and chemical threat agent that is soluble in water and does not exert a vapor pressure will generally exist in the soil in two phases as dissolved solute in soil water and as a sorbent to soil particles or organic matter. Mathematically, the partition of a specific chemical can be written as 

For solute diffusion coefficients independent of solute concentration, Equation (3.4.5) becomes 

If the initial concentration of the solute in the soil is negligible, only diffusion occurs, and there is no uptake of the solute the solute will diffuse downward, and the solute concentration distribution will be as follows  

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