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MNi4GEA5 OESIGYER4AON$y,lAttS and an 8,000 gallon tank (Tank 5) that currently contains GB11 Figure 3 presents the locations of existing USTs. In July and August 1994, WESTON conducted a soil and groundwater investigation at the site During the investigation, two soil borings (SB-1 and SB-2) were completed in proximity to the , former locations of Tanks 1 and 2 to determine the potential lateral extent of petroleum impacted soil Five soil samples were collected from each boring One boring was completed next to Tank 3 (HP-1) and one boring was completed next to Tank 4 (HP-2) Two soil samples and a Hydropunch'b groundwater sample were collected from each boring Figure 3 shows the locations of soil samples collected during WESTON's 1994 investigation , Three monitor wells, MW-1, MW-2 and MW-3, were installed in the vicinity of the Tank 1 and 2 excavation in July 1994 (Figure 3) The monitor wells were sampled in August 1994 and four times (quarterly) in 1995 If no contamination is observed during the removal of Tanks 7 and 8, these monitor wells will be abandoned as specified in Appendix A Table 2 presents groundwater depth and elevation data collected at the site Figure 4 presents typical groundwater contours and flow direction (August 1994) The highest groundwater elevations generally occur ' at the site during the spring and range in elevation from -21 81 to -21 94 ft MSL The lowest groundwater elevations generally occur at the site during the fall and range in elevation from -26.87 to -27 04 ft MSL Groundwater gradients have ranged from 0 013 to 0 0024 Groundwater flow is towards the north 3.0 NATURE AND EXTENT OF CONTAINATION 3.1 SOIL CONTAMINATION The results of analyses conducted on soil samples collected from the bottom of the tank excavations are summarized in Table 3 The results of the analyses conducted on soil samples collected from soil borings are shown in Table 4 EPA methods used to analyze the samples are also presented in the tables As illustrated in Tables 3 and 4 total petroleum hydrocarbons- extractable (TPHe) is the primary contaminant detected in soil e Tanks 1 and 2 1 Figure 5 presents TPHe concentration contours for soil found initially at Tanks 1 and 2 Soni contaminated with up to 5,500 mg/kg of TPHe was removed from the excavation down to a depth of 27 ft below ground surface (bgs) in 1987 A sample collected from the bottom of the U1PR0JECIS\SANJ0Q19JCMVCD 2 3 May 1996 ,