The site is located in Lac Du Flambeau, Wisconsin on the Indian Reservation of the Lac Du Flambeau Band of Lake Superior Chippewa Indians (Tribe). It is located next to Tower Creek and near Haskell Lake. This site most recently operated as a fireworks stand until a fire in October 2006 damaged the building. The local volunteer fire department responded and used significant amounts of water to extinguish the fire. The water-soaked, partially burned fireworks debris remained in the building until July 2007 when the Tribe received a Brownfields grant for debris removal. The Tribe then performed a Phase II environmental site assessment using another Brownfields grant to sample soil, groundwater, and nearby drinking water wells. The samples showed the presence of perchlorate and metals in the soil perchlorate in the groundwater.
In December 2007, the Tribe contacted the USEPA with concerns over the contaminated groundwater. USEPA and START (Superfund Technical Assistance and Response Team) conducted a site visit in January 2008 and determined a full site assessment was needed. The site assessment was conducted by USEPA and START from May 12 to May 14, 2008. During the assessment samples collected included wipe, sediment, surface water, soil, and groundwater. Sample results found perchlorate in soil at concentrations ranging from 120 to 990 milligrams per kilogram and in ground water at concentrations ranging from 9.8 to 120 micrograms per liter. Both mediums exceed the Region 9 Preliminary Remediation Goals for residential soil and tap water. Based on the fact that some Tribal members still live off the fish they catch and the food they grow, results from the site assessment, and recommendations from the USEPA Water Division and the Agency for Toxic Substances and Disease Registry, the determination was made to perform a Removal Action.
During the week of November 3, 2008 removal activities included completion of excavation of contaminated soil and hauling of waste.
Approximately 382 tons of contaminated soil was excavated and stockpiled. Confirmation samples were collected from the walls and floor of the excavation. All confirmation sample analytical results for perchlorate were below the Region 9 Preliminary Remediation Goals for residential soil, with levels ranging from 0.20 to 428 parts per billion (ug/kg).
Fourteen loads of concrete mixed with rebar were hauled off site to a local recycler.
Approximately 6,000 gallons of septic waste from an underground septic tank was removed and disposed of by A-1 Septic, Lac Du Flambeau, Wisconsin.
During the week of November 11, 2008 removal activities included hauling all non-hazardous soil off-site, installation and sampling of three ground water monitoring wells, site cleanup and demobilization.
Approximately 382 tons of non-hazardous perchlorate contaminated soil was hauled off site and disposed of at the Waste Management Valley Trail RDF Landfill in Berlin, Wisconsin.
The excavated area was backfilled with fill provided by the Lac Du Flambeau Tribal Roads Department. The excavated area was graded and rye seed was spread over the entire site.
Three ground water monitoring wells were installed and developed by Badger State Drilling. A temporary well was installed and ground water samples were collected. The temporary well and a pre-existing water well on site were both appropriately abandoned.
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Groundwater samples will be collected from the newly installed monitoring wells in the spring of 2009 and if necessary in the fall of 2009. Results from these samples will determine whether removal of the contamination source has limited further contamination of the groundwater or if other remediation activities are needed.
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