Geological characterization and solute transport model investigations of contaminated sites in urban areas (Denmark)

In Denmark, contaminations from industry and farming represent a significant threat to groundwater resources. On a national level, there is a focus on identifying and locating these contaminated sites. Once located, contaminations are mapped and monitored and remediation efforts are undertaken. Remediation is time consuming and expensive and it is often difficult to identify the original source of the contamination that would otherwise give indications to its extent and composition. Moreover, as cities grew, many contaminations are now located in urban areas where data compilation and remediation efforts are often challenged by logistics. The general lack of knowledge about theses contaminations introduces significant uncertainties in the projections on the fate of the contaminant.
We carry out a geological characterization of two contaminated sites situated in urban areas. The existing data from the two field sites includes only lithological profiles from boreholes. In order to increase the density of the field data, the two areas were mapped with Electrical Resistivity Tomography (ERT). Based on the borehole information and the high-density geophysical data, detailed 3D geological models of the two sites were constructed. The 3D geological models serve as a basis for simulating groundwater flow and contaminant transport at the field sites. The study demonstrates how detailed information about the geological setting in conjunction with contaminant transport modelling, can minimize the uncertainties of projections on the fate of the contaminant.
Based on the work, we were able to pinpoint the best strategies and solutions for future remediation efforts at the two sites.