Groundwater Flow and Contaminant Transport Analysis of the Kitzville Dump, St. Louis County, Minnesota

Abstract

The Kitzville Dump was used as a municipal and industrial solid waste disposal site for approximately 35 years. After the site was closed and capped in 1981, chemical analyses of monitoring wells installed at the site indicated leachate was entering the groundwater. Two confined glacial outwash aquifers overlie Precambrian bedrock at the site. Hydrogeologic characteristics determined at the site indicate the general groundwater flow direction to be from the northwest to the southeast at an average rate of 20 ft/yr. A three-layer groundwater flow model provided the basis for analysis of solute transport at the site. The solute transport model was initially calibrated to chloride. Additional contaminants analyzed were benzene, toluene, cadmium, and lead. Retardation factors were determined for each of these chemical species. Results of the solute transport model indicate that the contaminant plume is moving in the general direction of groundwater flow. The migration rate varies among the chemical species analyzed, with chloride having the highest and cadmium the lowest rate. The extent of the contaminant plume does not pose a threat to any existing water supplies; however, future development in the area would necessitate further testing to ensure that health standards are maintained.