ARCHIVED REPORTS_XR0005722 - Laserfiche WebLink

Home Browse Search

I _ ' 26 September 2002 • AGE-NC Project No 95-0173 ' Page 4 of 8 ' 4.0. FINDINGS Ground water elevation, flow direction and gradient were determined from field data collected on ' 20 June 2002, the contaminant Impact to ground water was quantified from the ground water laboratory data ' From field and laboratory data collected at the SVE remediation system between 11 March 2002 and 11 June 2002, AGE determined the average TPH-g concentration, the average flow rate and calculated the approximate mass and volume of hydrocarbons removed 4 1 GROUND WATER ELEVATION AND GRADIENT ' During the June 2002 ground water monitoring event,depths to ground water in the monitoring wells were measured between 25 65 and 28 17 feet below the tops of well casings,ground water elevations were calculated to be between 17 03 feet (MW-8) and 18 20 feet (MW-5) below mean sea level Ground water elevation at the site decreased an average 0 29 feet between the March 2002 and the June 2002 groundwater monitoring events Nine of the wells were"drowned",the screened-Interval was approximately 3 feet below the water table in wells MW-1 through MW-4 and between 10 and 30 feet below water In wells AW-lA through AW-2B ' The ground water elevation data for the June 2002 ground water monitoring event is depicted in Figure 3 Ground water flow direction at the site was Inferred to be toward the northeast at a gradient of 0 004 ft/ft or less, or approximately 22 feet per mile (Figure 3) I4 2 LABORATORY RESULTS OF GROUND WATER SAMPLES A total of sixteen ground water samples were submitted to Castle Analytical Laboratory (CAL), a DHS-certified laboratory, for analysis TPH-g was detected In ground water samples collected from wells MW-1 through MW-4, MW-6, AW-1A, AW-1B, AW-2A and AW-2B, at concentrations as high as 160,000 micrograms per liter (gg/1) In the sample from AW-2A BTEX compounds were detected in ground water samples collected from wells MW-1 through MW-4, MW-6, AW-lA, AW-1B, AW-2A and AW-213 at concentrations as high as 35,000 µg/l (toluene, AW-2A) The maximum benzene concentration was detected from sample AW-2A at a concentration of 13,000 µg/1 MTBE was detected in water samples collected from MW-4 and MW-5 at concentrations as high as 11 µg/1 (MW-4), 1,2-DCA was detected in a water sample collected from MW-5 at a IAdvanced Geo Environmental,Inc