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i '18 January 2001 1 AGE-NC Project No. 95-0109 ;Page 2'of4 2.2. COLLECTION OF GROUND WATER SAMPLES The depth to water was remeasured'after purging to ensure a.mininnum of 80.per,cent'recharge prior to sampling.'Water samples were collected from each purged well using disposable plastic bailers. Immediately upon retrieval, the samples'were transferred into three 40-m1 EPA-approved VOA vials containing 0.5inl 18%hydrochloric acid as a sample preservative. The samples were labeled, stored- on ic_ e; and transported in a chilled container, under chain-of-custody, to McCampbell Analytical, ;. Inc. (MAI), a State of California' Department 'of Health Services (DHS)-certified analytical laboratory.-All samples were analyzed for: Total petroleum.h drocarbons quantified as. gasoline (TPH-g) in accordance with EPA _ .. r.Methods-503a/8015m; Volatile. aromatic compounds -benzene, toluene, ethylbenzene'and xylenes (BTEX) and• methyl'tertiary-butyl ether(MTBE) in accordance with EPA method 80201602;.and ' Volatile organic compounds including fuel oxygenates - di-isopropyl ether.(DIPE), ethyl tertiary-butyl ether (ETBE), MTBE, tertiary-amyl methyl ether (TAME), tertiary butanol . (TBA), ethanol and methanol in accordance with EPA Method 8260M. '. 3.0. FINDINGS Groundrwater elevation and,flow direction were calculated from field data; hydrocarbon-impact to ' ground.water was quantified by laboratory analysis.of the groundwater samples. ; 3.1. GROUND WATER GRADIENT AND DIRECTION The deptli to ground water.ranged'from 50.89 feet bsg north of the site to 53.83 feet bsg south of the site during..the December 2000 monitoring-,event. Ground water elevation, in each well was ' determined by subtracting the'deptli.to water from the well head elevation. Groundwater elevations at the site increased an average of 0.39 feet between the September 2000.and December.'2000' '• monitoring events,`Ground water'elevation contours, based upon data collected on 15 December 2000;are depicted in'Figure 3: The inferred ground water flow direction is toward the south. Ground water elevations are summarized on Table 1. is � : � , : : , . . _ , . . _ : . •• . •x , • , . :- : , .. ;. 1 Advanced GeoEnvironmental,Ihic.