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I 1 ' A 1 1' 7 October 2003 AGE-NC Project No 96-0235 ' Page 2 of 5 ' I i ' 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 25 and 60, gallons of water were removed from each of the wells (a minimum of 3 casing-water volumes per ; ' "column 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 r ' water analyzer Field sheets and data are included in Appendix A Purged water was stored on-site in labeled, 55-gallon DOT-approved drums I 1 2 3 F 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-m1 volatile organic analysis (VOA) vials containing 0 5 ml 18% ' hydrochloric acid as a sample preservative and into 1-liter amber bottles without preservative After collection, the samples were properly labeled, placed in a chilled container and transported under ' • chain-of-custody to Cal Tech Environmental Laboratories(CTEL),a State of California Department of Health Services (DHS)-certified analytical laboratory, and were analyzed for o Total petroleum hydrocarbons quantified as (TPH-g) and as diesel (TPH-d) in accordance ' with EPA Method 8015M, ' o Benzene,toluene,ethylbenzene and total xylenes(BTEX)andthe fuel additives di-isopropyl ' t ether(DIP E),ethyl tertiary-butyl ether(ETBE),methyl tertiary-butyl ether(MTBE),tertiary- amyl methyl ether (TAME), tertiary-butyl alcohol (TBA), methanol, ethanol, 1,2- dibromoethane (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B ' i r PI 4 ' r 3.0 FINDINGS r 4� - ' 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 fieldL i I i 3 11 GROUND WATER GRADIENT AND FLOW DIRECTION • Depths to ground water ranged from 16 91 feet to 19 80 feet below the tops of the well casings, ground water was within the screened intervals of the shallow wells,but was approximately 112 feet Advanced Gen Environmental,Inc i 1 I I I I