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26 June 2002 <br /> AGE-NC Project No 95-0141 <br /> Page 2 of 4 <br /> 2 2 COLLECTION AND LABORATORY ANALYSIS OF GROUND WATER SAMPLES <br /> A water sample was collected from each well using a new, clean, disposable plastic bailer <br /> Immediately upon retrieval, the sample was transferred into three properly labeled 40-m1 EPA- <br /> approved VOA vials containing 0 5 ml 18%hydrochloric acid as a sample preservative The samples <br /> were logged on a cham-of-custody farm,stored in a chilled container and transported under chain-of- <br /> custody to Cal Tech Analytical Laboratories (CTEL), a California Department of Health Services <br /> (DHS)-certified laboratory The ground water samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015 Modified, <br /> • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary-butyl ether <br /> (MTBE) in accordance with EPA Method 8021, and <br /> • The oxygenated compounds di-isopropyl ether (DIPE), ethyl tertiary-butyl ether(ETBE), <br /> MTBE, tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), 1,2-dibromoethane <br /> (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B, <br /> . respectively <br /> 30. FINDINGS <br /> Ground water elevations and flow directions were inferred from field data Hydrocarbon-impact to <br /> Iground water was characterized from laboratory analytical data <br /> I3 1 GROUND WATER ELEVATION AND GRADIENT <br /> The average depth of ground water on 17 May 2002 was 19 6 feet below casing top, the average <br /> groundwater elevation of the seven shallow groundwater monitoring wells was approximately 1198 <br /> feet below mean sea level (MSL) Ground water was inferred to flow radially outwards toward the <br /> southwest, south and southeast from a ground water high in the vicinity of MW-4, at gradients <br /> Iranging between 0 002 ft/ft and 0 004 ft/ft <br /> The ground water table occurred within the screened intervals of wells MW-7 and MW-8 but was <br /> I between 9 20 and 10 69 feet above the screened intervals in monitoring wells MW-1 through MW-5 <br /> Monitoring well MW-6 was designed as a piezometer, with a 5-foot screened interval set at <br /> approximately 40 feet below the water table, since it possibly is monitoring a different hydraulic <br /> zone, MW-6 was not used to determine gradient and flow direction <br /> • <br /> Advanced GeoEnvironmental,Inc <br />