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( S t -+ 16 October 2003 AGE NC Project No 96-0235 Iry I , Page 2 of 5 ' After recording water level measurements, each of the 24'wells was purged of standing water utilizing a Waterra inertial pump or a dedicated disposable plastic bailer, between 5 and 60 gallons of water were removed from each of the wells(a mmzmum of 3 casing-water volumes per well) ,For ' the intermediate and deep wells, ground water was purged from near the top of the water column to remove water trapped within the non-screened interval of the well 'casings Ground water temperature,pH and conductivity were measured at regular purge-volume intervals using an Oakton ' water analyzer Field sheets and data are included in Appendix A Purged water was stored on-site in labeled, 55-gallon DOT-approved drums t2 1 2 Collection and Analysis of Ground Water Samples Water samples were collected from each purged well using new disposable plastic bailers after } ' allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume Each water sample was transferred into 40-rnl volatile organic analysis (VOA) vials containing 0 5 ml 18% ' hydrochloric acid as a sample preservative and Into 1-liter amber bottles without preservative rAfter collection, the samples were properly labeled, placed in a chilled container and transported under chain-of-custody to McCampbell Analytical,Inc (MAI),a State of California Department of Health Services (DHS)-certified analytical laboratory, and were analyzed for lie TPH-g and TPH-d in accordance with EPA Method 8015M, ' a BTEX and the fuel additives DIPE, ETBE,MTBE, TAME, TBA, methanol, ethanol,EDB and 1,2-DCA in accordance with EPA Method 8260E 3.0 FINDINGS I 1 The hydrocarbon-impact to ground water was quantified by laboratory analysis of'the ground water samples Ground water elevation and gradient was determined by utilizing data collected from the field i ' 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION i I s Depths to ground water ranged from 17 19 feettto 20 33 jeet below the tops of the well casings, ground water was within the screened intervals of the shallow wells,but was approximately 10 9 feet above the screened interval of intermediate wells MW-3 and EW-2 and between 19 67 and 47 57 feet above the screened intervals of the deep wells , ' The elevation ofound water in each well was calculated b subtracting the depth to ground water gr' Y from the surveyed casing elevations (Table 1) Ground water elevations at 'the site ranged from a t Advanced GeoEnvironmental,Inc 1 t