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µ+ruGERS oes�veAscaxsutwn w excavation at a depth of 27 ft contained 12 mg/kg of TPHe Soil samples collected above the ' estimated high groundwater table north and south of the excavation contained 2.1 mg/kg to 7 1 mg/kg of TPHe Soil samples collected between the estimated high groundwater table and the ' August 1994 water table contained up to 11 mg/kg of TPHe Benzene, toluene, ethylbenzene, and xylene (BTEX) were not detected in soil samples. ' An estimated 16,610 fe of soil containing an estimated 900 lbs TPHe was removed during the excavation of Tanks 1 and 2. Figures 6 and 7 present the horizontal and vertical extent of TPHe ' remaining in soil following the removal of Tanks 1 and 2 The estimated extent of petroleum impacted soil remaining in place is 53,200 fe Based on an average TPHe concentration of 6 39 ' mg/kg the estimated mass of TPHe present in soil is 32 lbs I Tank 3 The Figure 5 presents TPHe concentration contours for soil found initially at Tank 3 Trichlorofluoromethane (TCFM, a refrigerant likely related to laboratory refrigeration of the samples), TPHe, and total lead were detected at 0 15 mg/kg, 50 mg/kg, and 12 7 mg/kg, respectively, in a sample collected from the bottom of the excavation Soil contamination at Tank 3 is limited to an area immediately beneath the Tank 3 excavation, where TPHe was detected at 50 mg/kg TCFM was also detected in soil, however, there is no known use for TCFM at this site, and it is most likely a laboratory contaminant The maximum concentration of total lead (12.7 mg/kg) detected in soil beneath the excavation is well below the total threshold limit concentration of 1,000 mg/kg for lead and is most likely naturally occurring. ' An estimated 7,250 fe of soil containing an estimated 17 lbs TPHe was removed during the excavation of Tank 3 Figure 6 presents the horizontal extent of TPHe remaining in soil following the removal of Tank 3 The estimated extent of petroleum impacted soil remaining ' in place is 660 ft' The estimated mass of TPHe present in soil is 1 6 lbs Tank 4 i ' Figure 8 presents the extent of TPHe in soil at Tank 4 TCFM and TPHe were detected at 0.18 mg/kg and 70 mg/kg, respectively, from the bottom of the excavation The TCFM detected is most likely a laboratory contaminant The maximum concentration of total lead (11 3 mg/kg) detected in soil beneath the excavation is well below the total threshold limit concentration of 1,000 mg/kg for lead and is most likely naturally occurring f 1 L\PROJEC1WANJOQ+SJCMVCD 3 3 May 1946