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i J I i R > > 1 I i i 17 October 2003 I € AGE-NC Project No 96-0235 1 , "Page 3 of 5 above the screened interval of intermediate wells MW-3 and EW-2 and between 20 04 and 47 19 feet above the screened intervals of the deep wells J I i i ' ;The elevation of ground water in each well was calculated by subtracting the depth to ground water from the surveyed casing elevations (Table 1) Ground water elevations at the site ranged from 1111 `1 78 feet (MW-8A) to 13 31 feet (MW-2) below mean sea level The average ground_water elevation in the wells increased by approximately 0 28 feet since the March 2003 ground water monitonng event , ' Figure 3,and Figure 4 illustrate the ground water potentiometric surface based on the shallow- and, deep-'screened datasets Near the former UST cluster, the shallow-screened data delineate a radial ground water flow pattern, with a net flow towards the east at a gradient of 0 002 ft/ft, the deep- screened data delineated a radial ground'water flow direction toward the northeast at a gradient of 0 003 ft/fl Near the former UST No 3 excavation ground water flow direction at the shallow- screened level was inferred to be towards the southeast at a gradient of 0 005 fUft,ground water flow direction at the deep-screened level was inferred to be toward the south-southwest at a gradient of ,0 015 ft/ft 3 2 ANALYTICAL RESULTS OF WATER SAMPLES TPH-g was detected In the samples collected from MW-1, MW-2, MW-10, EW-1 and EW-2 at concenvations as high as 86,000 micrograms per liter (µg/1) in the sample collected from EW-1 TPH-d was detected in samples collected from MW-2 and EW-at concentrations of 19,000 4gil and 29,000 µg/1, respectively I � ' BTEX compounds were detected in samples MW-1,MW-2,MW-10,EW-1 and EW-2 at maximum'', 'concentrations of 2,400µg/]benzene(MW-1), 1,600 pg/l toluene(EW-1),2,200 µg/1 ethylbenzene ' (MW-1) and 3,320 µg/1 xylenes (EW-1) MTBEzwas detected in the water samples collected from MW-9,MW-10,MW-12B,MW-13(A and ; B), MW-14B and EW-Pat concentrations ranging from 7 0 µg/1'(MW-13A}tor340=µg/1{EW-1} ' Water samples analyzed from MW-2, MW-1113, MW-14B and EW-2 contained detectable concentrations of 1,2-DCA at'5 9 µg/1, 9 3 µg/1 and 8 0 µg/1,respectively Concentrations ofDIPE, ETBE, TAME, TBA, methanol, ethanol'and EDB were not detected'above laboratory reporting ' limits in any of the water samples c6llected during the June 2003 monitoring event I Analytical results of water samples collected during the second quarter of 2003 are summarized on ' Table 2 and 3,analytical results from previous monitoring events are summarized on Tables 4 and 5 iFigures 5 and 6 Illustrate'tlh`e ground water contamination plumes in upper and lower ground water � Advanced GeoEnvironmental,Inc I I � 1 I 1