Sustainable Environmental Clean-up : Dynamic assessment for sustainable remediation of contaminated sites

Abstract: Soil and groundwater contamination is an increasingly recognised threat to public health and the environment around the globe. New types of contaminants continue to emerge, and awareness of their threat, continues to develop. Many countries have national clean-up programs with priority lists of the most hazardous contaminated sites. Investigation and remediation of these sites, however, take a long time. An important reason is that dealing with contaminated sites has high practical complexity and uncertainty, making it hard to decide whether a specific remedy measure should be implemented. This depends not only on hydrological and biogeochemical heterogeneities and variabilities at a site, but also on associated health, environmental, economic, and social impacts of taking or not taking an action in the long run. Contaminant fate and transport models help to understand and predict subsurface behaviour and potential risks. As well, sustainability assessment tools can help in the decision-making process. These tools aim at quantifying environmental, economic, and social impacts and comparing different scenarios of remediation to give an overview of all potential impacts with time. However, integration of contaminant transport models and sustainability assessment tools has not been performed, leading to a lack of a holistic but pragmatic view of the whole system. This could admittedly result in fixing one problem while generating new ones. Thus, this thesis integrates these into a novel system that recognizes variations of involved factors in time. For this, a contaminant transport model (INSIDE-T) and a sustainability assessment tool (INSIDE) were developed with the aim of coupling through a system dynamics approach and simulations, for its unique capabilities in integrating multiple types of data/information sources. This integration can provide a holistic, but pragmatic guide for decision-making in remediation actions. The new tool, DynSus, enables site managers to assessconsequences of their decisions in site clean-up projects in terms of contaminant spread risk, social, environmental, and economic impacts from a dynamic life cycle perspective. For this, experience from experienced site managers and stakeholders is used and the methodology is implemented, among others, on a seriously contaminated site in Sweden overseen by the Swedish Geological Survey as the main case study of the thesis. The results show that ”gentle” remedy measures, which are often considered sustainable, may not be the best options in terms of life cycle impacts, although they generally gain significantly higher sustainability scores at the beginning of the remediationprocess. The time these measures rank below more invasive methods is calculated by DynSus.