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sy= -'�': , -q- -..- o-_z_ c r - Z x�1=. -._ _ - ___x � 4 -'z __-_S _ � t _�Y' .z -__•--+• y=-:.,y-�l_c r, r -v... s s__ r,- _f - __�_ a I fr 1 23 October 2003 _ AGE-NC Project No 97-0312 r` Ige3 of 4 Pa 1 I r � , 3 11 GROUND WATER ELEVATION AND GRADIENT Depths to ground water at the site ranged between 62 18 to 62 93 feet below top of casing (btoc), ground water elevations were between 34 16 feet (UST-2, UST-4) and 34 28 feet (UST-6) below _ mean sea level (MSL) The average ground water elevation had increased by an average of 3 0 feet since the December 2002 monitoring event The!ground water table occurred above the screened IJ intervals of monitoring wells UST-2 through UST-4, the ground water table occurred within the screened intervals of momtoringrwells UST-5 and UST-6 Monitoring well UST-7 was designed to monitor deeper ground water,with a 5-foot screened interval set at approximately 24 feet below the water,table, since It possibly is monitoring a different hydraulic zone, UST-7 was not used to - determine gradient and flow direction F , General ground water flow direction at the site was inferred to be northwest with an averagegradient of approximately 0 0006 ft/ft or less Figure 3 depicts the ground water elevation contours for I 1 February 2003 I Monitoring data from USTI 2,UST-3 and UST-4 was combined with monitoring data collected from ' the adjacent Moore Truck Lines=property to determine an approximate regional groundtwater flow direction ' ' � r 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES 1 - - During the February 2003 monitoring event,,TPH-g, benzene and 1,2-DCA were detected in the _ sample collected from UST-5 at concentrations of 270 micrograms per liter(µg/1),4 3 µg/1 and 300, µg/1,respectively`TPH-d was detected'in the sample collected from UST-3 at a concentration of 62' 1, ' µg/1 MTBE ani 1,2-DCA were detected in the sample collected from UST-6 at concentrations of 1 ! 0 73 µg/1`and 64 µg/1;respectively Tetrachloroetherie was detected in the sample collected from ' UST-7 at a concentration,of 0 74 µg/1 „ I ; Icy � ` � { , 1 No`other target analytes were detected at,or above laboratory reporting levels in the,ground water- - samples collected this quarter The laboratory reports ,(MAI 'Lab IDs' 030231,5-001 through , ' 0302315-007)and chain-of-custody forms are included in Appendik B Analytical results of water - samples collected during the first quarter 2003 are summarized on Tables 2 and 3 The analytical results of all water samples are summarized onryTables 4 and 5 Flgixres 4;5 and`6 illustrate the areal' ' extent of TPH-g/d-, benzene- and 1,2-DCA-impacted ground water, respectively� 1 � ! f i ” I I i I 1 9 Advanced GeoEnvlronmental;Inc I 10 1 2 I I 1 I s