The paper describes a series of theoretical aspects concerning residual soil pollution by heavy metals. Heavy metals, unlike organic and radionuclide pollutants, are considered to be the most persistent/resistant polluting substances in the soil, displaying a tendency for accumulation. The behavior of heavy metals in the soil depends on the physical and chemical properties of the soil, as well as on their origin and source. Knowledge of the properties of heavy metals is very important, having in view the necessity of applying isolation measures for a contaminated site.
