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, <br /> 16 December 2005 <br /> 1 AGE-NC Project No 98-0465 <br /> Page 5 of 6 <br />' 5.0. SUMMARY AND CONCLUSIONS <br /> Based on data collected at the site, AGE concludes <br />' a The ground water elevations on-site ranged from 7 98 to'8 15 feet below MSL Ground <br /> water flow at the UST location was inferred to be dominantly towards the northeast under <br />' a gradient of 0 002 ft/ft to 0 003 ft/ft <br /> • BTEX compounds were not detected in the ground water samples collected and analyzed <br /> during the Third Quarter 2005 s I <br />'} <br /> TPH-g was detected in the ground water sample collected from well MW-1 at <br /> 1 concentration of 350 pg/l Historically, TPH-g has not been detected above laboratory <br />' reporting limits in monitoring wells MW-2 through MW-4 <br /> • MTBE was detected in samples collected from MW-1 and MW-3 at concentrations of <br />' 350 pg/l and 12 µg/1, respectively The concentration of MTBE in MW-1 exceeds the <br /> Primary State and Federal established maximum containment level (MCL) of 13 µg/1 for <br /> MTBE in drinking water However, the MTBE concentration in MW-3 has dropped to dust <br /> below the MCL since the 2"d quarter monitoring event <br />' • • The lateral and vertical extent of MTBE-impacted ground water has historically been defined <br /> I <br /> in all directions, in the north by well MW-2, in the east by borings B-1 and B-4, in the south <br />' by boring B-5, and in the west by borings B-2 and B-3 During this quarterly monitoring <br /> event,grab groundwater samples were not taken from any of the borings,however,definition <br />' of the MTBE-impacted ground water to the north(in the direction of ground water flow) is <br /> still confirmed by MW-2, suggesting that the plume has not migrated significantly since the <br /> last,quarter <br />' Based on the available data it is not likely that the MTBE plume at the adjacent Sanchez <br /> property is co-mingled with the MTBE Plume at the Country Club Food and Fuel site <br /> Though the non-detect, northwestern boundary of the MTBE plume at the Country Club <br />' Food and Fuel site (Figure 4) was determined by soil sample results from boring locations <br /> B-2 and B-3'dated 30 March 2005; it is highly improbable that the plume could have <br /> migrated the 75+ feet northwest necessary for commingling, especially given the low v <br />' hydraulic gradient of 0 002 ft/ft found at the site and the northeasterly flow of ground water <br /> inferred for this quarter <br /> 1 1 I 5 ♦ ' t <br /> f <br /> I <br /> 4 <br /> l <br /> i <br /> I � <br /> u <br /> Advanced GeoEnvironmentai,Inc <br /> I <br /> 1 � <br /> , <br />