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GROUNDWATER GRADIENT AND FLOW DIRECTION Figure 4 shows the groundwater elevation gradient and flow direction determined from depth to water measurements at the three on-site monitor wells on May 22, 2001 The groundwater elevation has increased by an average of 0 1 ]feet at the three monitor wells since the previous quarterly monitoring round on March 16, 2001 The flour direction is to the east The o%erall gradient is 0 001 feet/linear foot RESULTS OF CERTIFIED ANALYSIS OF GROUNDWATER SAMPLES The results of the certified analyses of groundwater samples collected from the three monitor wells on May 22, 2001 are shown in Table 1 Copies of the laboratory reports are included as Appendix C of this report TPH-G concentrations ranged from a maximum of 10,000 ug/l at monitor well NIWl to 1900 ug/l at monitor well MW2 Benzene concentrations ranged from a maximum of 4,400 ug/l at MW1 to 570 ug/l at MW2 MTBE was not detected in concentrations above the laboratory detection limits of 25 ug/l (MW2), 50 ug/1 (MW')), and 200 ug/1 (MVI) Figure 5 shows the distribution of TPH-G, BTEX, and MTBE in groundwater and tine estimated lateral limits of the TPH-G in groundwater as deteimined fiom groundwater samples collected on May 22, 2001 INSTALLATION OF GROUNDWATER MONITORING WELL MW4 DRILLING AND SOIL SAMPLE COLLECTION Woodward Drilling Company, under the supervision of a WEGE geologist, drilled and installed one on-site groundwater monitoring well, MW4, on June 12, 200I The drilling contractor used a mobile rig equipped with 8-inch diameter hollow stem augers to drill the monitoring well Figure 3 shows the location of the monitor well Monitor well MW4 was dr riled to a total depth of 80 feet bgs Groundwater was encountered at approximately 25 feet bgs Relatively undisturbed soil samples were collected at 10, 15 and 20 feet bgs No soil samples were collected below 25 feet because SBI, located approximately 3 feet east of MW4 adequately characterized the soil conditions between 25 and 80 feet bgs Soil samples were collected in 2-inch X 6 inch clean brass sleeves using a 140 lb slide hammer and a California split spoon sampler The soil samples were field screened for the presence of odor, vapor, and visible staining In addition, each sample was field-screened for total volatile organic vapors with a photo- ionizing detector (PID) equipped with a 10 2 EV lamp 3 Arc Pump QM 4-6, 2001