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1 ' 09 January 2006 • AGE-NC Protect No 98-0497 ' Page 2 of 4 ' water volumes per well) were purged from all the wells using a Waterra Hydro-LIR II pump equipped with a mechanical arm utilized to surge each well with dedicated tubing Ground water temperature, pH, and conductivity were measured at regular intervals during purging using an Oakton water analyzer Field sheets and data are included in Appendix B Purged water was stored on-site m properly labeled,Department of Transportation(DOT)-approved 55-gallon drums pending proper disposal 2 3 GROUND WATER SAMPLE COLLECTION ' Prior to the collection of ground water samples,the depth to ground water was r - measured in each ' monitoring well to ensure that a minimum 80% of the initial water volume had recharged Water samples were collected from each well using the inertia pump and dedicated tubing The water was transferred into one 1-liter amber bottle and three 40-milliliter(ml)volatile organic analysis(VOA) ' vials containing 0 5 ml 18% hydrochloric acid solution as a sample preservative After collection, the samples were labeled and placed in a chilled container for transport under chain of custody to Cal Tech Environmental Laboratories(CTEL), a California Department of Health Services(DHS)- ' • certified analytical laboratory in Paramount, California The samples were analyzed for • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, respectively) in accordance with EPA Method 8015M, and • Benzene,toluene,ethylbenzene,and total xylenes(BTEX)and fuel additives methyl tertiary- butyl ether (MTBE), di-isopropyl ether (DIPS), ethyl tent-butyl ether (ETBE), tert-amyl methyl ether(TAME), and tertiary butanol (TBA) by EPA Method 8260B 3.0. FINDINGS ' Ground water elevation and flow direction were inferred from field data Hydrocarbon-impact to ground water was assessed by laboratory analysis of the ground water samples ' 3 1 GROUND WATER ELEVATION AND GRADIENT At the time of the June 2005 sampling event, depths to ground water at the site ranged from 64 90 feet(MW-5)to 65 72 feet(MW-4)below the tops of the well casings Ground water elevation at the ' site averaged approximately 40 42 feet below mean sea level(MSL),indicating an average increase in ground water elevations of 0 16 feet since the last monitoring event in March 2005 Ground water . elevation data is included in Table 1 Advanced GeoEnvironmentel,Ine