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' 10 June 1999 • AGE-NC Project No. 95-0185 Page 2 of 4 transferred into two 40-m1 volatile organic analysis(VOA)vials containing 0.5ml 18%hydrochloric ' acid as a sample 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 McCampbell Analytical, Inc. (MAI). Each sample was analyzed in accordance with the following: • EPA Method 8015 Modified for total petroleum hydrocarbons quantified as gasoline and as diesel (TPH-g and TPH-d), • EPA Method 8020 for volatile aromatic compounds (benzene, toluene, ethyl-benzene and 1total xylenes: BTEX) and • EPA Method 8260 Modified for oxygenated fuel additives di-isopropyl ether(DIPE), ethyl tertiary butyl ether (ETBE), methyl-tert-butyl ether (MTBE), tertiary amyl methyl ether ' (TAME) and tertiary butyl alcohol (TBA). 3.0. FINDINGS 1• Ground water relative elevations were determined from field data, and the concentrations of petroleum hydrocarbons were determined by laboratory analysis by an independent DHS-certified analytical laboratory. r 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 well MW-4, which was assigned an arbitrary elevation of 60 feet. During the March 1999 sampling event,the depth to ground water below the tops of the well casings at the site ranged from 17.45 feet to 18.10 feet. The screen interval of the monitoring wells were appropriate to obtain representative samples of the upper most ground water. The average ground water elevations have relatively remained the same since the last quarterly monitoring event in December 1998. Using the relative ground water q Y elevation measurements,the ground water gradient was calculated to be 0.006 for 25 March 1999, directed radically toward the'west from well MW=4 (former UST location);with the flow'direction varying from the Northwest to the Southwest. 3 Advanced GeoEnvironmentai,Inc. {