The role of geotechnics in the risk assessment procedure for polluted sites

The National Environmental Code made the site-specific risk assessment an essential tool for the management and remediation of contaminated sites. The paper underlines the role of geotechnical expertise for Risk Assessment of contaminated sites and illustrates specific aspects, also derived by practical applications. The paper offers an overview of the risk assessment procedure and points out how the appropriate definition of the subsoil model greatly affects the formulation of the assessment and, consequently, the risk results and the remediation design. The effects of several soil parameters affecting the risk assessment procedure and results are examined and the application of new techniques in evaluating the migration pathways are described and discussed. With reference to the migration models implemented in computer codes, the paper addresses the importance of appropriate model to predict contaminant leaching and transport to groundwater and the issue of contaminant volatilization by comparing results of commonly used volatilization models and direct measurements of vapor emissions.