A multidisciplinary approach to evaluate the effectiveness of natural attenuation at a contaminated site

This study evaluates the natural attenuation of chlorinated hydrocarbons as remediation action in a contaminated site downtown the city of Parma (Italy). To achieve this goal, a combination of new investigation methods (bio-molecular analysis, compound specific isotope analysis, phytoscreening) has been proposed. The approach (named circular multi step) allows to: fully understand the phenomena that occur at the study site, design new investigation activities, and manage best practices. Consequently, each step of the approach improves the conceptual and numerical models with new knowledge. The activities carried out at the study site allowed to detect a contamination of perchloroethylene in a large part of the city of Parma and, of main importance, underneath a kindergarten. The results of the study did not show significant natural attenuation of chlorinated hydrocarbons and that the detected contamination could refer to the same unknown contaminant source. Furthermore, the innovative phytoscreening technique was applied to assess the presence of chlorinated hydrocarbons at the ground level. The plume spread was estimated through numerical modeling starting from potential contaminant sources. This study enhances the knowledge of groundwater flow and contamination in Parma and allows authorities to design new investigation/reclamation activities through management actions.