A decision support tool for conceptual site model development at contaminated sites

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Environmental Engineering, Turkey

Approval Date: 2009




A conceptual site model (CSM) is simply a description of the environmental conditions at a contaminated site and surrounding area, which provides all interested parties with a vision of the site. CSM mainly identifies the source-pathway‐ receptor linkage to guide for effective site characterization, risk assessment and remedial investigations. Development of CSM is complicated because it is ‘case specific’ and there is no single route to follow during decision making concerning the contaminated site. Moreover, type and extent of information needed varies according to size and level of contamination and site heterogeneity. The objective of this study is to develop a decision support tool that guides the site assessors during identification of possible decision routes that can be encountered; the procedure to be followed; and the information and data to be collected at each stage. This tool also introduces interactions between CSM andsampling strategies designed for various purposes. Developed decision support tool adapts to each specific contaminated site. Furthermore, a detailed review of sampling strategies is presented as a guidance for site assessors. The decision support tool is equipped with standardized tools used for CSM development, i.e. information/data collection forms, illustrative tools and exposure pathway diagram. Information on site, geology, hydrogeology, contamination source, contaminants and receptors is collected via CSM form. Illustrative tools may vary from very simple site sketches to very complex 3D drawings depending on the needs of the specific contamination cases. Exposure pathway diagram (EPD) is used to identify all transport mechanisms and potential exposure pathways. EPD is embedded into a user‐friendly decision assistance tool based on Microsoft Excel and Visual Basic for Applications. The applicability and utility of the decision support tool was tested using two case studies. Case study applications indicated that the developed methodology satisfies the objectives aimed in this study.