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I <br />' 22 March 1999 <br /> • AGE-NC Project No 95-0143 <br />' Page 2 of 5 <br />' 2 2 COLLECTION OF GROUND WATER SAMPLES <br /> Water samples were collected from each well for both monitoring events using new, disposable <br />' bailers and, upon retrieval,were transferred into 40-m1 EPA-approved VOA vials containing 0 5 ml <br /> 18% hydrochloric acid as a sample preservative The samples were labeled and transported under <br /> chain-of-custody, in a chilled container, to McCampbell Analytical, Inc (MAI), a California <br />' Department of Health Services (DHS)-certified analytical laboratory in Pacheco, California The <br /> samples were analyzed for <br /> I0 Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 5030/8015 <br />' a Volatile aromatic compounds (benzene, toluene, ethylbenzene and xylenes BTE&X) with <br /> methyl tertiary-butyl ether (MTBE) in accordance with EPA Method 602, and <br /> I Oxygenated compounds (dr-isopropyl ether [DIPE], ethyl tert-butyl ether [ETBE], MTBE, <br /> tert-amyl methyl ether [TAME] and tert-butanol [TBA]) in accordance with EPA Method <br /> 8260 <br /> • Samples collected during the November 1998 monitoring were also analyzed for volatile organic <br /> compounds in accordance with EPA Method 8260 <br /> 3.0. FINDINGS <br /> I3 1 GROUND WATER ELEVATION AND GRADIENT <br /> The elevation of ground water in each well was calculated by subtracting the depth to water from <br /> the surveyed casing elevation (Table 1) Due to suspect data, ground water elevations and flow <br /> direction for 03 November 1998 were not calculated Between August 1998 and February 1999, <br /> ground water elevations decreased an average of I 1 I feet During the February 1999 monitoring <br /> event, ground water was within the screened interval of MW-17 and near the top of the screened <br /> interval in MW-16 Ground water was above the screened interval of the remaining wells at the site <br /> from almost one foot above the screened interval in MW-15 to 7 6 feet above the screened interval <br /> in MW-3 The approximate hydraulic gradient was calculated to be 0 001 ft/ft with a northeasterly <br /> flow direction on the subject property However, a steeper gradient of 0 003 ft/ft was measured north <br /> of the site Ground water elevation contours for the February 1999 monitoring event are illustrated <br /> in Figure 3 <br /> I <br /> I <br /> Advanced GeoEnvironmental,Inc <br />