Contaminated sites: a comparison between the Italian and the Swedish approach

Abstract: The assessment of the risk posed by a polluted site towards humans and the environment is an important issue. The methodology to define a conceptual model of the site of study and to perform the risk assessment can differ significantly for each country thus, the comparison between different methods to approach polluted sites, can highlight which are the aspects that should be included or modified in the risk assessment methodology to ensure reliable outcomes. The aim of the study was to compare the Italian and Swedish approaches to deal with contaminated sites and evaluate the respective results. The two risk assessments were performed for the property of Bollnäs Bro 4:4, located in Bollnäs (Sweden). The site presented a diffused contamination by both inorganic and organic pollutants as a consequence to the storage and maintenance of train coaches. Soil samples were taken on site to perform leaching test and determine the site-specific soil to liquid partition coefficient (Kd) of metals. Two software were used: Risk-net 2.0, to determine the threshold  concentrations for risk (CSRs), i.e. the Italian remediation goals, and the Software for site-specific soil guidelines by Kemakta AB to calculate the Swedish sitespecific soil guidelines. The outcomes of the two risk assessments were different both considering the value and the driving exposure pathway, but confirmed the critical pollution of the property. The Swedish site-specific guidelines were found smaller than the Italian CSRs for the majority of the contaminants, but it was not possible to define which approach would have determined the highest remediation costs, due to the non-legally-binding character of the Swedish guidelines. The Italian risk assessment is very detailed, but time consuming. The Swedish methodology, on the contrary, is quick and simple, but is lacking in site-specificity, due to the limited number of editable parameters. Both the approaches have strengths and weaknesses, but further studies, focused both on the physio-chemical and toxicological properties of the pollutants and the mathematical models adopted in each country, are required to perform a deepened comparison between the two methodologies.