Cleanup at Clark's Lane/Gilmore Avenue Ground Water Contamination Site in Winona

Approximately 25 area residences with impacted private drinking water wells were connected to City water as of November 1990, and the majority of the residents were awarded State compensation for water service replacement and for permanent sealing of their wells. In November 1990, Leaf's Services, Inc., under State order, was asked to respond to the contamination, and their response included the cleanup of two identified release areas. These two areas included an indoor drain and an outdoor "pit" that were both used for disposal of dry cleaning wastes. Subsequently, and beginning in 1991, the MPCA retained consultants and other support remediation services to investigate the extent and magnitude of the contaminant plume and to evaluate and design a ground water remediation system. MPCA contractors completed the installation of a groundwater remediation system in 1992, and conducted a soil gas survey of the site in 1998. From the soil gas survey, it was concluded that a significant mass of contaminated soil remains underneath and within 25 feet of Leaf's building. Soil vapor concentrations of PCE and trichloroethylene (TCE, a typical breakdown product of PCE), were observed at significant levels. The survey report also recommended that additional soil sampling be completed in order to better define the source zone of contamination.