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� : r 25 March 2003 AGE-NC Project No 98-0433 ' Page 2 of 5 ' 2 2 GROUND WATER SAMPLE COLLECTION a Prior to the collection of ground water samples, the depth to ground water was re-measured in each ' well to ensure that a minimum of 80% of the initial water volume had recharged Water samples were then collected from each well using a disposable plastic bailer In addition,a water sam le was collected from the domestic well(DW-1)on the site by allowing the well pump to operatey for one ' minute, then collecting a water sample from a dedicated sample tap The water from each monitonng_well was transferred into three chilled 40-m1 volatile organic ' analysis (VOA) vials containing 0 5 ml hydrochloric acid (lS%) as a sample preservative and one 1-liter amber bottle without preservative,water from the domestic well was poured directly into the sample containers from the dedicated sample tap After collection,the samples were labeled and placed In a chilled container for transportation under chain-of-custody t o C at T ech E nvironmental L aboratones, I ne (CTEL), a s tate o f C allfamia Department of Health Services-certified analytical laboratory Each sample was analyzed for • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d) in ' • accordance with EPA Method 8015 Modified and Benzene,toluene,ethyl benzene and total xylene(BTEX)and the fuel additives methyl butyf ' ether (MTBE), tertiary butyl alcohol (TBA), di-isopropyl ether (DIPS), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), ethylene 'Ibromids: (EDB), 1,2- dichloroethane (1,2-DCA), ethanol and methanol in accordance with EPA Method 8260B 1 3.0 FINDINGS 3 Ground water elevations were determined by subtracting the measured depths-to-water from the surveyed casing elevations Ground water flow directions were determined by contouring the water - elevations on a scaled'slte plan(Figure 3) The hydrocarbon-Impact to ground water was quantified by laboratory analysis of the ground water samples 3 1 'GROUND WATER GRADIENT AND FLOW DIRECTION During the January 2003 sampling event,the depth to ground water ranged from 22 75 feet(MW-3) to 24 88 feet(MW-1)below the top ofthe casing(btoc) However,the depth to ground water at wells ' MW-1 (24 88 feet)and MW-6 (24 41 feet)was affected by the presence of free product, the depths were recalculated at 24 69 feet and 23 60 feet btoc,respectively,utilizing the measured thickness of free product in the wells > ' Advanced GeoEnvironmenfal,Inc