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' 01 February 2005 <br /> • AGE-NC Project No 98-0497 <br /> Page 2 of 4 <br /> 2 2 GROUND WATER SAMPLE COLLECTION <br /> Prior to the collection of ground water samples, the depth to ground water was re-measured to each <br /> t monitoring well to ensure that a minimum 80% of the initial water volume had recharged Water <br /> samples were collected from each well using a clean, disposable plastic bailer The water was <br /> transferred into one 1-liter amber bottle and three chilled,40-milliliter(ml)volatile organic analysis <br /> (VOA) vials containing 0 5 ml hydrochloric acid solution (18%) as a sample preservative After <br /> collection,the samples were labeled and placed in a chilled container for transportation under chain- <br /> of-custody to Cal Tech Environmental Laboratories (CTEL), a Department of Health Services <br /> (DHS)-certified analytical laboratory Each sample was analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, <br /> ' respectively) in accordance with EPA Method 8015M, and <br /> • Benzene, toluene, ethylbenzene, and total xylenes (BTEX) and methyl tertiary-butyl ether <br /> ' (MTBE) in accordance with EPA Method 8021 <br /> ' . 3.0. FINDINGS <br /> Ground water elevation and flow direction were inferred from field data Hydrocarbon impact to <br /> ground water was assessed by laboratory analysis of the ground water samples <br /> ' 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> Ground water elevations were determined by subtracting the measured depths to water from the <br /> surveyed casing elevations The average ground water elevation at the site was 44 06 feet below <br /> mean sea level(MSL),the average depth to water was 68 98 feet below the tops of the well casings <br /> The average ground water elevation in the wells decreased by approximately 3 32 feet between the <br /> May and September monitoring events Ground water was within the screened interval of each <br /> monitoring well <br /> ' The water table flow direction at the former UST location was determined to be generally northeast <br /> under a hydraulic gradient of approximately 0 008 foot/foot(ft/ft) Figure 3 illustrates the contoured <br /> ' ground water elevations as measured on 28 September 2004 <br /> f <br /> 1 <br /> • <br /> ' Advanced GeoEnviron mental,Inc <br />