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LIKA Corporation advanced three soil borings in an upgradient <br /> direction from the sump and wet room wall. Based on these <br /> values, the copper and lead soil cleanup levels were estimated <br /> to be 35 and 10 mg/kg respectively. Onsite background soil <br /> concentrations were used as cleanup levels given the placement <br /> of dredged materials under the building. <br /> Excavation and removal of soils was the remedial action <br /> selected. Excavation and removal of soils from the interior <br /> sump, the interior strip, and the exterior strip was performed <br /> by LIKA Corporation (with Department oversight) as an Interim <br /> Remedial Measure from April to May, 1987. <br /> A total of 201 cubic yards of soil and concrete associated with <br /> the sump were excavated and taken to a Class 1 (hazardous waste) <br /> landfill. Analysis of post-excavation soil samples showed a <br /> copper concentration with a geometric mean of 36. 3 ppm (range <br /> 211-18 . 5) and a lead concentration with a geometric mean of 7 . 9 <br /> ppm (range 13 . 2-2 .7) for the sump excavation. <br /> A total of 198 cubic yards of soil and pavement associated with <br /> the exterior strip of contaminated soil were excavated and taken <br /> to a Class 1 (hazardous waste) landfill . Analysis of post <br /> excavation soil samples showed a copper concentration with a <br /> geometric mean of 33 . 9 ppm (range 104-25. 5) and a lead <br /> concentration with a geometric mean of 10. 5 ppm (range 14 .5-4 . 3) <br /> for the exterior strip excavation. <br /> A total of 49 cubic yards of soil and concrete associated with <br /> the interior strip of contaminated flooring was excavated and <br /> taken to a Class 1 (hazardous waste) landfill. Analysis of post <br /> excavation soil samples showed a copper concentration with a <br /> geometric mean of 33 . 9 ppm (range 43-27 . 5) and a lead <br /> concentration with a geometric mean of 7 . 9 ppm (range 8 . 5-7. 0) <br /> for the interior strip excavation. <br /> Soils directly beneath the exterior wall footing were unable to <br /> be excavated. The copper concentration of soils under the <br /> footing had a geometric mean of 43 . 7 ppm (range 2255-26) and a <br /> lead concentration with a geometric mean of 10.7 ppm (range <br /> 15. 1- <8. 5) . <br /> Groundwater seeping into the sump area during excavation was <br /> stored on site in Baker Tanks. Water quality constituents of <br /> the collected groundwater were analyzed. Three tanks met <br /> Stockton Municipal Code (SMC) requirements for the discharge of <br /> wastewater and were disposed into the regional sewer line. <br /> Three other tanks revealed the need for pretreatment; one tank <br /> was too basic in pH and while two others contained copper <br /> concentrations above SMC standards. LIKA Corporation <br /> transported these tanks to 1443 Navy Drive where they were <br /> treated in the LIKA pretreatment system. Interior monitoring <br /> wells not destroyed during soil excavation were sealed accord- <br />