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AOC Work Plans <br /> collected at a depth of 10 feet from the north end of the bum pit contained 11,000 mg/kg of copper <br /> and 1,500 mg/kg of lead. <br /> Following excavation of the burn pits in 1994, SSSE collected 11 soil sam les from the excavation <br /> walls and floors of the bum pits(at depths between 6.0 and 13 feet bgs)an I analyzed them for the <br /> copper,chromium, lead,nickel,and zinc only. Laboratory analyses detec d copper,chromium, <br /> lead,and zinc at concentrations of 25 to 39 mg/kg,24 to 36 mg/kg,4.0 to .1 mg/kg, and 35 to 57 <br /> mg/kg respectively,all well below their respective residential PRGs. The ocation of these samples <br /> within the burn pits was not provided in any of the reports reviewed by TVL kCTEC. <br /> In 2001,AGE drilled boring PB 11 down-gradient of the north bum pit. 0 ie grab groundwater <br /> sample was collected and analyzed for metals, formaldehyde,and VOCs. Formaldehyde and <br /> dissolved lead were detected at concentrations of 120 gg/L and 0.032 m respectively. Both <br /> concentrations are above their applicable PRGs; 100 µg/L for formaldehyc e, and 0.015 mg/L for <br /> dissolved lead. <br /> Between 1999 and 2004,three different sampling events were performed c n the stockpiled soil <br /> removed from the bum pits and former teepee structure(discussed above ii i Section 4.2) stockpiled <br /> just north of the northern burn pit(Plate 4.2). Based on the results of the f nal sampling event in <br /> 2004,the soil was properly disposed of offsite in June 2004. There is no evidence that <br /> confirmation sampling of native soil took place after removal of the stockpiles. <br /> Data Gaps <br /> Additional sampling is necessary along the sidewalls and floors of the two blue pits to confirm all <br /> soils in excess of their respective residential PRGs have been removed. In addition,formaldehyde <br /> and dissolved lead were detected at concentration above their respective re 3idential PRGs in a <br /> groundwater sample collected down-gradient of the north bum pit. Installation of several borings <br /> Draft <br /> KB61125 workplan-ESC MACTEC Engineering and Consulting, Inc. 34 <br /> September 28,2005 <br />