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1 i <br /> 03 April 2002 <br /> AGE-NC Project No 98-0534 <br /> 1 Page 2 of 4 <br />' 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> After the depth to ground water was measured to ensure that a minimum of 80% well-volume <br />' recharge had been achieved, a water sarni ple was collected from each well using a dedicated and <br /> disposable plastic bailer Immediately upon retrieval, samples were transferred into one-liter amber <br /> bottles and three 40-m1 EPA-approved volatile organic analysis(VOA)vials containing 0 5 ml 18% <br /> hydrochloric acid as a sample preservative The samples were logged on a chain-of-custody form, <br /> stored in a chilled container under ice The samples were later transported under chain-of-custody <br /> to Cal Tech Environmental Laboratories (Cal Tech), a State of California Department of Health <br />' Services (DHS)-certified analytical laboratory for analysis The samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and diesel (TPH-d) in <br />' accordance with EPA Method 8015 Modified, <br /> • Benzene, toluene, ethylbenzene and total xylenes(BTEX)in accordance with EPA Method <br /> 8020, and <br /> • Oxygenated compounds - di-isopropyl. ether (DIPE), ethyl tertiary-butyl ether (ETBE), <br /> methyl tertiary-butyl ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary butanol <br /> (TBA), ethanol,methanol, 1,2-dibromoethane(EDB) and 1,2-dichloro ethane(1,2-DCA)in <br /> accordance with EPA Method 8260-Modified <br /> 3.0. FINDINGS <br /> Ground water elevation flow direction and <br /> , gradient were determined from field data collected on <br /> 08 January 2002, the contaminant impact to ground water was assessed from the laboratory data <br /> 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> The relative elevation of ground water In each well was calculated by subtracting the depth to ground <br /> water from the relative casing elevation(Table 1) The average depth to ground water on 08 January <br /> 2002 was 7 8 feet below the tops of the well casings,presently the water table is above the screened <br /> interval of the wells Ground water was inferred to be flowing towards the north and south away <br /> I from an east-west trending hydraulic saddle at the main UST area,with a gradient of approximately <br /> 0 009 to 0 01 feet/feet (see Figure 3) The ground water elevation of monitoring well MW-5 <br /> appeared anomalously high, above the range of the surrounding wells by 1 9 feet,therefore the data <br /> from that well was not used to map the ground water elevation <br /> Advanced GeoEnvironmental,Inc <br />