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Y <br /> 5 <br /> f3 <br /> W <br /> , <br /> 12 May 2000 <br /> AGE-NC Project No 97-0312 G <br />' Page 2 of 4 - r <br /> For the large domestic well, a drain valve was opened on the water storage tank The pump was <br /> allowed to cycle on and off several times For the small domestic well;a faucet between the well and <br /> ,= the water,holding tank was opened to allow the pump to cycle several times <br /> 22 COLLECTION OF GROUND WATER SAMPLES <br /> IThe depth to water was re-measured following purging to assure a minimum of 80% recharge prior <br /> to sampling Water samples were retrieved from each purged well using new disposable bailers For <br />' the domestic wells, a sampling port was opened at the well head Samples were collected from the <br /> sampling port only while the pump was operating, to assure fresh water was sampled Each sample <br /> was transferred Into 40-m1 EPA-approved VOA vials containing 0 5 ml of 18% hydrochloric acid <br />' as a sample preservative and Into 1-liter amber bottles without preservative The samples were <br /> labeled, placed in a chilled container and transported under chain-of-custody to McCarnpbell <br /> Analytical Inc (MAI) In Pacheco, a California Department of Health Services (DHS)-certified <br />' analytical laboratory The samples were analyzed for <br /> a Total petroleum hydrocarbons quantified as gasoline (TPH-g) and diesel (TPH-d) In <br /> _ accordance with EPA Methods 5030 and 8015m, <br /> a Volatile aromatic hydrocarbons benzene, toluene, ethylbenzene and total xylenes (BTEX) <br /> with methyl tertiary-butyl ether (MTBE) In accordance with EPA Method 8020/602, and <br /> a Volatile organics and fuel oxygenates MTBE, di-isopropyl. ether (DIPE), ethyl tert-butyl <br /> ether (ETBE), tert-amyl methyl ether (TAME) and tert-butanol (TBA) In accordance with <br /> EPA Method 8260 modified <br /> I <br /> 30. FINDINGS <br />' Ground water elevations were determined by, subtracting the measured depths-to-water from the <br /> surveyed casing elevations (Table 1) 'Ground water flow direction was determined by contouring <br /> the water elevations on a scaled site plan '(Flgure 4) Hydrocarbon-Impact to ground water was <br /> Inferred from laboratory analysis and field observations <br /> I3 1 GROUND WATER ELEVATION AND GRADIENT <br /> N <br /> Ground water elevation Increased an average of 8 41 feet at the site since the December 1999 <br /> monitoring event A greater'Increase in ground water elevation was observed at the former USTs <br /> location, while a lesser Increase was observed at the north end of the site Ground water flow <br /> Advanced GeoEnvironmental,Inc <br /> Y ' <br /> I � x <br /> C <br />