Some aspects of the state of the art of contaminated sites remediation in Italy

The remediation of contaminated sites has been faced in Italy and elsewhere in the world with a series of works originated by the availability of specific technologies for the recovery of soils and groundwater quality, acting in accordance with the principle of sustainability. A framework of rules (target values and type of intervention) and a summary of the quality of soil and groundwater in Italian contaminated sites must be mentioned first. The design of the remediation was also permitted by the improvement of the site characterization, with specific equipments addressed for example to identify the stratigraphy of the contaminants, the presence of volatile compounds, the sampling of water of significant groundwater quality, etc.. The text describes some interventions relating to physical and hydraulic barriers that involve substantial capital and O&M costs and also the consumption of natural resources. Subsequently they are also considered important in situ interventions that resulted in a reduction in the concentration and significant recovery of the pollutants mass. The evolution of the residual concentration in the groundwater must be considered by monitoring natural attenuation. Despite the recovery of the mass of pollutants even up to 90-99%, values of cleanup (expected concentrations of the order of μg/L) which are established by national legislation have not been achieved. It can be stated that the scientific community is considering the new paradigm expressed by the "order of magnitude of the flow of pollutant mass" to replace the old paradigm consisting in the "limit value of final concentrations".