ENVIRONMENTAL GEOLOGY AND THE INVESTIGATION, REMEDIATION AND REDEVELOPMENT OF A FORMER MANUFACTURING SITE IN MINNEAPOLIS, MINNESOTA

Historical uses of this Minneapolis site have included: a former battery manufacturer, stores, clinics, a dairy, residences and farmland. Redevelopment plans include a five-story mixed commercial and residential use building with an underground parking garage.

The local geology consists of 2 to 21 feet of uncontrolled fill on top of Des Moines lobe outwash sands with a layer of clayey sand at approximately 10 feet below ground surface. Debris found in the fill soils during the initial investigation include: battery casings, concrete, glass, bituminous, transite pipe, lumber, cinders, ash, scrap metal and flooring materials. This overlies the Prairie du Chein dolostone bedrock found 300 to 400 feet below ground surface.

Contaminants found on the site include: lead, arsenic, selenium, volatile organic compounds (VOCs), polyaromatic hydrocarbons (PAHs), asbestos and petroleum. These are believed to be mostly associated with the battery manufacturer. Remediation of the site included the excavation of two main areas of high lead, arsenic, and selenium concentrations to 13 feet below ground surface. The soil was mixed with Enviroblend®, a chemical used to leave metal-bearing soils non-hazardous, stockpiled and tested for disposal at the landfill. The top 4 feet of soil on the site, which contained low levels of lead, arsenic, selenium, VOC and PAH contamination, was directly loaded into trucks and transported to the landfill. Contamination from petroleum was noted from 4 to 15 feet below ground surface and was subsequently tested, excavated and hauled to the landfill.