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' 24 March 1999 <br /> . AGE-NC Project No. 95-0185 <br /> Page 2 of 4 <br /> 2.2. COLLECTION OF GROUND WATER SAMPLES <br /> A water sample was collected from wells MW-2 and MW-3,using a new disposable plastic bailer, <br /> and was transferred into two 40-m1 VOA vials containing 0.5ml 18%hydrochloric acid as a sample <br /> preservative and into one 1-liter amber bottle without preservative. After collection, the samples <br /> were placed in a chilled container and transported under chain-of-custody to McCampbell <br /> ' Analytical, Inc. (MAI). Each sample was analyzed in accordance with the following: <br /> • EPA Method 8015 Modified for total petroleum hydrocarbons quantified as gasoline and as <br /> ' diesel (TPH-g and TPH-d), <br /> EPA Method 8020 for volatile aromatic compounds (benzene, toluene, ethyl-benzene and <br /> ' total xylenes: BTEX) and <br /> • EPA Method 8260 Modified for oxygenated fuel additives di-isopropyl ether (DIPE), ethyl <br /> tertiary butyl ether (ETBE), methyl-tert-butyl ether (MTBE), tertiary amyl methyl ether <br /> ' (TAME) and tertiary butyl alcohol (TBA). <br /> 1• <br /> 3.0. FINDINGS <br /> ' Ground water relative elevations were determined from field data, concentrations of petroleum <br /> hydrocarbons was determined by laboratory analysis by an independent DHS-certified analytical <br /> ' laboratory. TPH-d was encountered in ground water samples from MW-2 and MW-3; monitoring <br /> wells that have yielded samples impacted by TPH-g were not sampled this quarter. <br /> ' 3.1. GROUNDWATER GRADIENT AND FLOW DIRECTION <br /> The relative elevation of ground water in each well was calculated by subtracting the ground water <br /> depth from the surveyed casing elevation. Monitoring well casing elevations were surveyed relative. <br /> to MW-4,which was assigned an arbitrary elevation of 60 feet. During the December 1998 sampling <br /> ' event,the depth to ground water below the tops of the well casings at the site ranged from 17.76 feet <br /> to 18.20 feet in well MW-4, however correcting for the free product in the well the depth to water <br /> is calculated to have been approximately 17.15 feet. <br /> The screen interval of the three located monitoring wells were appropriate to obtain representative <br /> samples of the upper most ground water. <br /> Ground water elevations have decreased an average 1:32 feet since the last quarterly monitoring <br /> ' event in monitoring wells MW-2 and-MW-3..With only two points of reliable relative ground water _ <br /> Advanced GeoEnvironmental,Inc. <br /> 1 <br />