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• 31 October 2003 AGE-NC Project No 95-0173 Page 4 of 8 3 2 COLLECTION AND ANALYSIS OF VAPOR EXTRACTION AIR FLOW SAMPLES Between 20 March 2003 and 23 June 2003, a total of three pairs of extracted air flow vapor samples were collected from the influent and effluent of the SVE unit to measure concentrations of hydrocarbon vapor Air flow samples were not collected during the 20 March 2003 monthly monitoring event due to SVE operations being temporanly suspended for repairs and maintenance The air flow vapor samples were collected in Tedlar bags using a hand air-vacuum pump Following sample collection,the samples were properly labeled,placed in a covered container and transported under chain-of-custody to McCampbell Analytical Inc (MAI)in Pacheco, California Each sample was analyzed within 72 hours of collection for TPH-g, BTEX and MTBE in accordance with EPA Methods 5030/8015M Modified and 8020 4.0, FINDINGS Ground water elevation, flow direction and gradient were determined from field data collected on 24 June 2003, the contaminant impact to ground water was quantified from the laboratory analysis iFrom field and laboratory data collected at the SVE remediation system between 20 March 2003 and 23 June 2003, AGE determined the average TPH-g concentration, the average flow rate and calculated the approximate mass and volume of hydrocarbons removed 41 GROUND WATER ELEVATION AND GRADIENT During the June 2003 ground water monitoring event, depths to ground water ranged between 27 25 and 29 87 feet below the tops ofwell casings,ground water elevations were calculated to be between 18 63 feet(MW-8)and 19 93 feet(MW-5)below mean sea level Ground water elevation at the site decreased an average 0 10 feet between the April 2003 and the June 2003 ground water monitoring events The ground water elevation data for the June 2003 ground water monitoring event is depicted in Figure 3 Ground water flow direction at the site was inferred to be oriented east across the site, at approximate graaients of 0 002 ft/1-t or less, or approximately 11 feet per mile 42 LABORATORY RESULTS OF GROUND WATER SAMPLES A total of nineteen ground water samples were submitted to CAL for analysis TPH-g was detected in ground water samples collected from wells MW-I through MW-4,MW-6,MW-9,MW-1 3(A and Advanced GeoEnvironmental,Inc