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i, i� z 09 January 1998 AGE-NC Project No. 95-0185 Page 2 of 4 preservative and into one 1-liter amber bottle without preservative. After collection, the samples ' were placed in a chilled container and transported under chain-of-custody to Mc Campbell Analytical, Inc. (MAI). Each sample was analyzed as follows: By EPA Method 8015 M for total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d), By EPA Method 8020 for volatile aromatic compounds(benzene,toluene,ethyl-benzene and total xylenes: BTE&X) and methyl-tert-butyl ether(MTBE), and ' By EPA Method 8260 for other oxygenated fuel additives tertiary butyl alcohol (TBA), di- isopropyi ether (DIPE), ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME) and to confirm and quantify MTBE detected by EPA Method 8020. ' 3.0. FINDINGS 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION The relative elevation of ground water in each well was calculated by subtracting the ground water ' depth from the surveyed casing elevation. Monitoring well casing elevations were surveyed relative to MW-4, which was assigned an arbitrary elevation of 60 feet. During the October 1997 sampling event, the depth to ground water below the tops of the well casings at the site ranged from 20.89 to 21.54 feet. The average ground water elevation of the property has decreased approximately 3.44 feet since the last quarterly monitoring event. The ground water flow direction determined from the data collected during the October 1997 sampling event was toward the southeast,at a hydraulic gradient of 0.0038 ft/ft. The relative ground water elevations at the site are contoured on Figure 3 - Relative Ground Water Elevation. ' Ground water at the site has a very. ry low gradient.rent. At such a low gradient, normal measurement error can equal or even surpass the differences between wells, and can greatly influence the inferred ' ground water flow direction determination. The regional ground water flow direction is generally southwest. With a low gradient on the site, small measurement errors or minor changes of local recharge and/or discharge of ground water canproduce the observed variation of ground water flow direction from the expected-regional'flow direction to the obserrved flow direction. ' 3.2. LABORATORY RESULTS OF GROUND WATER SAMPLES TPH-d-was detected in groundwater samples collected froln'monitoring wells MW-1, MW-2,MW-3 Advanced GcoEmironmental,Inc.