Procedural Steps in Human Risk Assessment for Contaminated Sites: An Italian Case-Study Application with the ARA-CoSSSLs Approach

Within the increased attention to the absolute risk assessment for potentially contaminated sites at the Italian level, the definable ARA-CoSSSLs modeling approach for human health protection was recently derived with predominant reference to the USEPA SSLs procedure. The basic aim of the ARA-CoSSSLs applications regards the possible technical-scientific improvement and better understanding of significant aspects in carrying out the human risk assessment at a given site. Particularly, the final reliability of the human risk assessment depends on the scientific plausibility of the procedural steps implemented during the elaboration of the available site investigation and information data. In this perspective, this article deals with the procedural elaboration steps conceived and implemented for the ARA-CoSSSLs casestudy application at a potentially contaminated subarea of a major Italian priority industrial site. Specific indications and aspects are addressed in the paper on the following procedural steps: (1) the usefulness of selection criteria for contaminants of concern; (2) the consideration of the possible soil gas loss (during drilling and/or sampling and/or analytical operations) for a reliable definition of subsurface representative concentrations for organic contaminants; (3) the geostatistical definition of the site areal extent, with a proposed conservative scenario in case of sparse spatial concentration data.