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t <br /> 29 October 2004 <br /> AGE-NC Project No 97-0351 <br /> ' Page 2 of 4 <br /> ' 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each monitoring well using the dedicated, disposable plastic <br /> bailer or Waterra check bailer after allowing the well to achieve a minimum 80%recovery of the pre- <br /> purge water volume The samples from each well were transferred into three 40-milliliter (ml) <br />- - volatile organic analysis(VOA)vials containing 0 5 ml 18%hydrochloric acid solution as a sample <br /> preservative The samples were labeled with the monitoring well designation,date,time of sampling, <br /> and the sampler's initials and transported in a chilled container under chain of custody to Cal Tech <br /> Environmental Laboratories (CTEL), a Department of Health Services (DHS)-certified analytical <br /> ' laboratory for analysis The samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> method 8015M, <br /> • Volatile aromatic compounds benzene, toluene, ethylbenzene, and total xylenes (BTEX) in <br /> accordance with EPA method 8260B, <br /> • Fuel oxygenates tertiary butanol(TBA),di-isopropyl ether(DIPE),ethyl tertiary-butyl ether <br /> (ETBE), tertiary-amyl methyl ether (TAME), and methyl tertiary-butyl ether (MTBE) in <br /> ' accordance with EPA method 8260B, and <br /> • Lead scavengers ethylene dibromide(EDB)and 1,2-dichloroethane(1,2-DCA)in accordance <br /> ' with EPA method 8260B <br /> ' 3.0 FINDINGS <br /> ' Ground water elevation and flow direction were inferred from field data, hydrocarbon impact to <br /> ground water was quantified by laboratory analysis of the ground water samples <br /> ' 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> '- The elevation of ground water in each of the monitoring wells was calculated by subtracting the <br /> depth to ground water from the surveyed relative casing elevations(Table 1) Depths to ground water <br /> averaged about 8 98 feet below surface grade(bsg) Ground water elevations at the site ranged from <br /> 0 95 feet (MW-5) to 107 feet (MW-2) above mean sea level (MSL) The ground water flow <br /> direction at the former UST area was generally toward the northeast with a calculated gradient of <br /> 0 001 foot/foot (ft/ft) During this monitoring event, the ground water elevations were within the <br /> ' screened intervals of the wells Figure 3 illustrates the contoured ground water elevations as <br /> measured on 06 August 2004 <br /> Advanced CeoEnvironmental,Inc <br />