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28 December 2004 <br /> AGE-NC Project No 01-0839 <br /> Page 2 of 4 <br /> I After collection, the samples were properly labeled, placed in a chilled container, and transported ; <br /> under chain of custody to Cal Tech Environmental Laboratories (CTEL), a California Department <br /> of Health Services-certified analytical laboratory, for analysis The samples were analyzed for <br /> • Total petroleum hydrocarbons as gasoline(TPH-g)in accordance with EPA Method 8015M, <br /> and <br /> • Benzene,toluene, ethylbenzene, and total xylenes(BTEX),di-isopropyl ether(DIPE), ethyl <br /> tertiary-butyl ether(ETBE),methyl tertiary-butyl ether(MTBE),tertiary-amyl methyl ether <br />' (TAME), tertiary-butyl alcohol (TBA), ethylene dibromide (EDB), and 1,2 dichloroethane <br /> (1,2-DCA) by EPA Method 8260B <br /> 3.0 FINDINGS <br /> The ground water elevation, flow direction, and gradient were determined from field data The <br /> contaminant impact to ground water was quantified by the laboratory analytical data <br /> I • <br /> 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> IAt the time of the August 2004 sampling event, depths to ground water ranged from 74 39 feet to <br /> 74 69 feet below the tops of the well casings (Table 1) Ground water elevations at the site ranged <br /> from 40 77 feet(MW-3)to 41 01 feet(MW-1)below mean sea level(MSL) During this monitoring <br /> event,the ground water level was within the screened interval of the wells, indicating that the wells <br /> were properly screened to yield representative shallow ground water samples <br /> IThe ground water flow direction was calculated from the well elevation data The net ground water <br /> flow direction was inferred to be towards the northwest at the former UST excavation at a gradient <br /> of approximately 0 004 ft/ft (Figure 3) <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in the water samples collected from wells MW-3 and MW-4 at concentrations <br /> of 5,300 micrograms per liter(µg/1) and 100 µg/1, respectively <br /> MTBE was detected in the water samples collected from wells MW-3 and MW-4 at concentrations <br /> of 4,900 µg/1 and 100 µg/l, respectively <br /> IAdvanced GeoEnvirnnmental,Inc <br /> I <br />