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i I08 August 2004 AGE-NC Project No 95-0128 IPage 2 of 4 I2 12 Ground Water Sample Collection A water sample was collected from each monitoring well using a new disposable bailer after ' allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume Immediately upon retrieval, the samples were transferred into three 40-milliliter (ml) EPA-approved volatile organic analysis (VOA) vials containing 0 5-ml 18% hydrochloric acrd (sample preservative) and I one 1-liter amber bottle without preservative The samples collected were logged on a chain of custody form,placed in a chilled container and transported to Cal Tech Environmental Laboratories (CTEL) a California Department of Health Services (DHS)-certified laboratory, for analysis The ground water samples were analyzed for • Total petroleum hydrocarbons quantified as gasoline and as diesel (TPH-g and TPH-d) in Iaccordance with EPA Method 8015 Modified, • Benzene, toluene, ethylbenzene and xylene (BTEX) in accordance with EPA 8260B, and • Fuel additives di-isopropyl ether(DIPE), ethyl tertiary-butyl ether(ETBE), methyl tertiary- butyl ether(MTBE),tertiary-amyl methyl ether(TAME),tertiary butanol(TBA),methanol, lie ethanol, 1,2-dibromo ethane (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B 3.0. FINDINGS Ground water elevations were determined by subtracting the measured depths to ground water from the surveyed casing elevations Ground water flow directions were determined by contouring the water elevations on a scaled site plan Contaminant impact to ground water was assessed by laboratory analysts 3 1 GROUND WATER ELEVATION AND GRADIENT I The depth to ground water in July 2004 ranged from 33 83 feet (MW-15) to 36 73 feet (MW-13) 1 elov" +I_ 11 'rl,o A ro« loY..Y+,,,,, 1..YY1—oil tlom the da" .nge 1 fTom . VVIV YY Llly YYe11 VUJ11150 111V &LVL111L YYl"LVi e1V Y11L1V11 VU1V Ul[1LVG 11 V,11 Lily .]allle 4LLLLN, rW1E,V�l 11 Vlll 21 86 feet(MW-7)to 23 92 feet(MW-17)below mean sea level(MSL) The depth to ground water increased approximately 1 2 feet since the last sampling event The ground water table occurred within the screened interval of the shallow-screened monitoring wells, however, wells MW-1 to MW-3,MW-11B,MW-12B and MW-18 are deeper-screened wells and are currently drowned The I depth to ground water and ground water elevation data is summarized in Table 1 The areal ground water flow direction was inferred to be east to northeast at gradients of between 0 005 ftlft to 0 406 ft/ft (Figure 3) Advanced GcoEnvironmental Inc I