Hydrogeologic controls on contaminant distribution within a multi-component DNAPL zone in a sedimentary rock aquifer in south central Wisconsin

This thesis study focused on the nature and hydrogeologic controls on a zone of multi-component DNAPL within the sedimentary bedrock near a former chemical recycling and distribution facility in south central Wisconsin. The DNAPL apparently entered the subsurface in the 1950s and 1960s and moved down through 27m of unconsolidated sand and gravel glacial overburden into the bedrock. The DNAPL flowed through 16 to 29m of the well- to poorly-cemented sandstone of the St. Peter Formation and accumulated in the underlying layered, silty, feldspathic sandstone of the Lone Rock Formation. The DNAPL zone contains free-product DNAPL, residual DNAPL, aqueous-phase, and sorbed VOCs consisting of aromatic, aliphatic, and chlorinated aliphatic compounds. Free-product DNAPL was observed in the upper 10m of the Lone Rock Formation between 43 and 53m below ground surface. Between 1999 and 2002, pumping of bedrock wells produced 34,000L (9000ga) of DNAPL from the Lone Rock. The DNAPL was recovered from a zone approximately 11m thick, 69m wide, and 92m long. (Abstract shortened by UMI.)...