Efficiency of capping contaminated sediments in situ. 2. Mathematics of diffusion-adsorption in the capping layer

Simple analytical models for hydrophobic organic pollutant release from a contaminated sediment capped (covered) with a clean material are presented. Three situations are considered: a base case of uncapped contaminated sediment, a case associated with high sediment contamination levels with essentially constant contaminated layer pore-water concentration, and a more general case in which the leaching of the pollutant from the contaminated sediment layer is considered. The model results are compared to experimental data from laboratory bench-scale simulators. Both models show generally good agreement with the experimentally observed fluxes, indicating that the fundamental transport mechanisms are well understood