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16 December 2004 <br /> • AGE-NC Project No. 95-0137 <br /> 1 Page 3 of 5 <br /> The soil-vapor sample was collected from the SVE effluent stream in a Tedlar vapor bag using a <br /> vacuum pump attached to the effluent stream.The sample was labeled,placed in a pre-chilled cooler <br /> and transported under chain of custody to transported to CTEL. The samples were analyzed for: <br /> ' Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015 Modified; and <br /> 1 Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary butyl ether <br /> (MTBE) in accordance with EPA Method 8020. ' <br /> AThe results of the laboratory analysis are included in Appendix C. <br /> 1 <br /> 3.0.- FINDINGS <br /> 1 Ground water elevation, flow direction and gradient were determined from field.data collected on <br /> 21 October 2004; the contaminant impact to ground water was quantified from the.ground water <br /> laboratory data. Soil vapor concentration were quantified from laboratory data. <br /> 1i . <br /> 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION <br /> Depths to ground water during the October 2004 monitoring event ranged from 25.24 to 26.05 feet <br /> below the well casing tops;the depth to ground water remained stable since the July 2004 monitoring <br /> ' event.The calculated ground water elevations ranged from 31.62 feet(MW-4)to 34.62 feet(MW-5). <br /> The ground water elevation calculated for well MW-2 was approximately one-quarter of a foot <br /> ' greater than the four surrounding well ground water elevations observed;this well did not produce <br /> the minimum of three-well volumes for the purge process and was slow to recharge after the well <br /> was purged.The calculated ground water elevation of well MW-2 was not used to determine ground <br /> water flow and gradient. <br /> r <br /> The ground water flow direction southeast of the former UST location was inferred to be northwest <br /> 1 - .� <br /> at a significant ground water gradient of 0.033 ft/ft,but was essentially flat northwest of the_former -,.. <br /> UST area(Figure 3). <br /> ' 3.2. ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> ' TPH-g, TPH-d and BTEX compounds were not detected in the ground water samples. The lead <br /> scavenger 1,2-DCA was the only contaminant detected,at a concentration of 51 micrograms per liter <br /> r <br /> 1 Advanced GcoEnvironmental,Inc. <br />