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14 May 2002 <br /> . AGE-NC Project No 98-0426 <br /> Page 3 of 5 <br /> 3 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each purged well using new disposable plastic bailers Each <br /> water sample was transferred into three 40-m1 VOA vials containing 0 5 ml 18%hydrochloric acid <br /> as a sample preservative After collection, the samples were properly labeled, placed in a chilled <br /> container and transported under chain-of-custody to McCampbell Analytical, Inc (MAI), a <br /> California Department of Health Services-certified laboratory The samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Methods 5030/8015 modified, <br /> • Benzene,toluene,ethylbenzene and xylenes(BTEX)and methyl tertiary-butyl ether (MTBE) <br /> in accordance with EPA Method 8020, and <br /> • The fuel oxygenates MTBE, di-Isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), <br /> tertiary-amyl methyl ether (TAME), and tertiary butanol (TBA) In accordance with EPA <br /> Method 8260 modified <br /> • 3 3 WELL HEAD SURVEY <br /> On 25 October 2001 and 05 March 2002,a California state-licensed survey engineer from Baumbach <br /> &Piazza,Inc surveyed the elevation of a reference point on the top of the casings of ground water <br /> monitoring wells MW4 and MW5 and MW1 through MW3, respectively, to the nearest 0 01-foot <br /> relative to City of Stockton Bench Mark Datum#26 at 9 90 feet above mean sea level (MSL) The <br /> results of the monitoring well survey are contained in Table 2 The surveying reports are presented <br /> in Appendix C <br /> I <br /> 4.0. FINDINGS <br /> Ground water flow direction and gradient'were Inferred from data collected in the field, the <br /> hydrocarbon impact to ground water was quantified by the laboratory data obtained from the ground <br /> water samples <br /> r4 1 GROUND WATER ELEVATION 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 elevations (Table 1) Depths to ground water ranged from 23 40 feet to <br /> 24 51 feet as measured from the top of the well casings, the water table was within the screened <br /> Advanced GeoEnvironmental,Inc <br /> I <br />