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' 20 May 1999 <br /> AGE-NC Project No 95-0142 <br />' Page 2 of 4 ` <br /> 2 2 GROUND WATER SAMPLE COLLECTION <br />' <br /> Water samples were collected from each purged well (MW-3, MW-4, MW-5, MW-6, and VW-1 <br /> through VW-4)using new,clean, disposable plastic bailers Immediately upon retrieval,the samples <br />' were transferred into EPA-approved 40-m1 VOA vials containing 0 5 milliliter hydrochloric acid <br /> (18%) as a sample preservative The vials were then labeled and placed in a chilled container The <br /> samples were transported under chain-of-custody to McCampbell Analytical, Inc (MAI) a DHS- <br /> certified laboratory in Pacheco, California for analysis Ground water samples were analyzed in <br /> accordance with <br />' EPA Method 8015 Modified for total petroleum hydrocarbons quantified as gasoline (TPH- <br /> g), <br /> • EPA Method 8020 for volatile aromatic hydrocarbons (benzene,toluene, ethyl-benzene and <br /> total xyelens BTEX), <br /> • EPA Method 8260 Modified for di-isopropyl ether(DIPE), ethyl tertiary butyl ether(ETBE), <br /> methyl tertiary butyl ether (MTBE), tertiary amyl methyl ether (TAME) and tertiary butyl <br /> • alcohol (TBA) <br /> 3.0. FINDINGS <br /> Ground water flow direction and gradient were calculated from the field data The current <br />' distribution of dissolved petroleum hydrocarbons was inferred from the laboratory analytical results <br /> from the ground water samples <br /> 31 GROUND <br /> WATER GRADIENT AND DIRECTION <br />' Depth to ground water at the site ranged from 24 85 feet to 25 69 feet below the well casing tops <br /> Between December 1998 and March 1999, ground water elevation decreased an average 147 feet <br /> The relative ground water elevation data is depicted in Table 1 During the December 1999 <br /> imonitoring event,the ground water flow direction appeared to be easterly The relative elevation of <br /> ground water surface at the site is illustrated on Figure 3 <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> ' TPH-g was detected in samples collected from wells V W-I through VW-4 at concentrations ranging <br /> • from 620 micrograms per liter(µg/1)to 190,000µg/1 TPH-g was detected in the samples collected <br /> Advanced GeoEnvironmental,Inc. <br /> i <br />