[Heavy metals: soil characteristics and methods of evaluating parameters for defining "contaminated soils"]

The excessive content of toxic elements in the human environment is associated with the etiology of a number of diseases. Soils' pollutants decontamination regards the main industrialised countries. Heavy metals represent the main problem for soil pollution characterisation. The first approach for pollution evaluation is the determination of total metal concentration; the evaluation of their bioavailability is required for a correct knowledge of the environmental risk. In the present work is shown the procedure to evaluate the sites, which require decontamination and which need the following data: knowledge of the threshold for each metal in the soil and its range, chemical analysis of the components, determination of bioavailability and soil destination. The bioavailability is easily calculated by the procedure of aimed extractions.