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15 December 2005 • AGE-NC Project No 98-0465 _ J Page 3 of 8 k adjacent site (Sanchez Property) ranged from 9 63 feet (MW-4) to 9 83 feet (MW-2) below MSL ' (Table 2) During this monitoring event, the ground water elevations were within the screened intervals of the wells The depth to water onsite and at the adjacent Sanchez property may have been ' "influenced by the pump and treat system located at the adjacent site and in operation for three days dust prior to the quarterly monitoring event This may in part explain the Linear depression in ground water gradient located at MW-2 on the Sanchez property,as well as the drop in average ground water- elevation this quarter (Figure 3) Onsite wells MW-1 through MW-4, and wells MW-2 through MW-7 on the adjacent site were used ' to model ground water flow direction and calculate the gradient The ground water flow direction was inferred generally towards the northeast at the former UST location,though as Figure 3 shows, the northern portion of Sanchez property exhibits a southerly ground water flow direction The hydraulic gradient was determined to be between 0 002 feet/feet (ft/ft) and 0 005 ft/ft Figure 3 illustrates the contoured ground water elevations as measured on 20 October 2005 Ir , 32 ANALYTICAL RESULTS OF QUARTERLY GROUND WATER SAMPLES ' • BTEX compounds were not detected at concentrations at or above the laboratory reporting limits in p rY p g any of the ground water samples TPH-g was detected in the ground water sample collected from ' MW-1 at a concentration of 440 µg/1 ' MTBE was detected in samples collected from MW-1 and MW-3 at concentrations of 440 µg11 and 55 µg11, respectively' No other fuel oxygenated compounds were detected in the ground water analysis at or above laboratory detection limits Analytical results of groundwater samples are summarized in Table 1 The laboratory report(CTEL Project No CT214-0510135), quality assurance/quality control report, and chain of custody forms are included in Appendix E Documents confirming the upload of laboratory electronic deliverable ' format (EDF) files and depth to water measurements to GeoTracker are included in Appendix F I J 1t i 4.0. SUMMARY AND CONCLUSIONS ' Based on data collected at the site, AGE concludes • The ground water elevations on-site ranged from 9 54 to 9 75 feet below MSL Ground ' water,flow at the UST location was inferred to be dominantly towards the north under a • gradient of 0 002 ft/ft to 0 005 ft/ft ' Advanced CeoEnvironmentai,Inc