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' 30 March 1999 <br /> AGE-NC Project No 96-217 <br />' Page 3 of 5 <br />' 3 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each monitoring well using a new disposable bailer The samples <br />' were transferred into four 40-m1 EPA vials containing 0 5 ml 18% hydrochloric acid as a <br /> preservative The samples were transported in a chilled container under chain-of-custody to <br /> McCampbell Analytical Inc (MAI) of Pacheco, California and analyzed in accordance with <br /> a EPA Method 5030/8015m and 602 for total petroleum hydrocarbons quantified as gasoline, <br /> volatile aromatic compounds (benzene,toluene, ethylbenzene and total xylene BTE&X)and <br />' methyl tertiary butyl ether (MTBE) , <br /> EPA Method 8260 for volatile organic compounds, and by <br />' a EPA Method 8260m for inethyl-tert-butyl ether MTBE and other oxygenated fuel additives, <br /> including tertiary butyl alcohol (TBA), di-isopropyl ether (DIPS), ethyl tertiary butyl ether <br />' (ETBE) and tertiary amyl methyl ether (TAME) and other volatile organic compounds <br /> 4.0 FINDINGS <br /> Data obtained at the site demonstrates the ground water elevation and flow direction on the subject <br />' property and the degree of petroleum hydrocarbon impact on ground watei as presented in the <br /> following subsections <br />' <br /> 41 GROUND WATER ELEVATION E ATION AND GRADIENT <br />' The elevation of ground water in each well was calculated by subtracting the depth to ground water <br /> from the surveyed casing elevation (Table 1) Monitoring well casing elevations were surveyed <br />' relative to monitoring well MW-1 Groundwater was approximately 0 6 foot higher than during the <br /> 23 September 1997 ground water monitoring event, and was approximately 0 4 feet higher than <br /> during the,I I July 1996 ground water monitoring event Ground water gradient on 18 November <br />' 1998 was calculated to be 0 004 ft/ft directed north 10' west, consistent with previous flow direction <br /> deteiminations The relative ground water elevation at the site is illustrated in Figure 3 <br />' 42 LABORATORY RESULTS OF GROUND WATER SAMPLES <br />' TPH-g was detected in ground water samples from monitoring wells MW-1 and MW-3 at <br /> concentrations of 270 µg/I and 180 µg11, respectively The same samples contained toluene, <br /> ethylbeiizene and total xylenes at maximuin concentrations of 1 5 /,cg/l, 1 0 µg11 and 1 4 gg/l, <br /> I <br /> Advanced GeoEmironrnental, Inc <br /> I <br />