The validity conditions of compartment models for cesium migration in
soils are investigated. A compartment model is derived from a diffusio
n-convection model. The model considers free and bound cesium compartm
ents and is applied to measured profiles of Cs-137 of undisturbed soil
in Northern Greece. It is concluded that the rate of cesium transfer
must vary linearly with depth and that from measured equilibrium profi
les, the ratios of model parameters can be determined but not the para
meters themselves.