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to08 June 2001 <br /> AGE-NC Project No 95-0103 <br /> ' Page 2 of 4 <br /> r <br /> 2 2 GROUND WATER SAMPLE COLLECTION <br /> Water samples were retrieved from each purged well using new disposable bailers The samples were <br /> ' transferred into 40-m1 EPA-approved volatile organic analysis (VOA) vials containing 0 5 ml <br /> hydrochloric acid (18%) as a sample preservative The samples were transported in a chilled <br /> container under chain-of-custody to McCampbell Analytical, Inc (MAI), a California Department <br /> ' <br /> of Health Services(DHS)-certified laboratory,for analysis The groundwater samples were analyzed <br /> for <br /> , <br /> ' • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015-modified for gasoline, <br /> ' • Purgeable aromatic compounds-benzene,toluene, ethyl-benzene and total xylenes(BTEX) <br /> with methyl-tert-butyl ether (MTBE) in accordance with EPA Method 8020, and <br /> • Oxygenating fuel additives-tertiary butyl alcohol(TBA),di-isopropyl ether(DIPE),MTBE, <br /> ethyl tertiary butyl ether(ETBE)and tertiary amyl methyl ether(TAME)in accordance with <br /> EPA Method 8260-modlfed <br /> 3.0. FINDINGS <br /> Ground water elevation and flow direction were calculated from field data, hydrocarbon-impact to <br /> ground water was assessed from laboratory analysis of the ground water samples <br /> 3 1 GROUND WATER ELEVATION <br /> Depth to ground water ranged from 10 06 to 12 02 feet below the top of well casings Ground <br /> water elevation increased approximately 141 feet between the November 2000 and May 2001 <br /> ' monitoring events The overall ground water flow direction ranged from the east-southeast to north- A <br /> northwest in the area of the former USTs Locally, in the former dispenser area, and extending <br /> southwest from MW-4,aground water table"low"elevation occurs The average hydraulic gradient <br /> was 0 006 ft/ft Figure 3 depicts the ground water elevation contours at the site <br /> ' 3 2 GROUND WATER ANALYTICAL RESULTS <br /> ' TPH-g was detected in samples from monitoring wells MW-1, MW-3, MW-4, MW-5, and vapor <br /> well VE-6 at concentrations of 4,100 microgram per liter (µg/]), 5,100 µg/1, 12,000 µg/1, 300 µg/1' <br /> and 8,700 µg/l, respectively <br /> ' Advanced GeoEnviron mental,Inc <br />