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15 December 2005 AGE-NC Project No. 03-1071 Page 13 of 14 (equivalent to 70 gallons per day/ft) and a storativity value calculated at 0 .00031 (Appendix J) . • Based on transmissivity values of 10 .6 W/day (first stage) and 9 .4 ft'/day (second stage) and an aquifer thickness of 20 ft (screen interval at EW- 1 ), hydraulic conductivity values were calculated at 0 .53 ft/day, or 1 .9 x 10° cm/s (first stage) and 0.47 May, or 1 .7 x 104 cm/s (second stage) (Appendix J); these hydraulic conductivities are consistent with a screened interval located within a silty fine sand. This suggests that although the pilot boring for EW- I encountered some coarser grained sand, the fine silty sand encountered between 30 and 55 feet bsg in previous pilot borings for MW- 1 through MW-4 is more characteristic of the aquifer (see the AGE-prepared Quarterly Report - First Quarter 2004, dated 15 June 2004). • Laboratory analysis of extracted water during the pumping test detected elevated concentrations of TPH-g, BTEX, MTBE, and 1 ,2-DCA in both samples submitted for analysis. Concentrations were as high as 61 ,000 µg/1 TPH-g, 9,900 µg/I benzene, 23,000 pg/l toluene, 2,500 µg/1 ethylbenzene, 18,200 µg/1 xylenes, 220 pg/l MTBE, and 230 µg/1 1 ,2-DCA. All concentrations detected were significantly above the respective MCLS for each contaminant. • On 23 August, a' SVE pilot test was conducted at the site. The SVE unit was operated at approximately 2,500 RPMs for the seven-hour test, with a flow rate measured between 30 scfm (standard cubic feet per minute) and 36 scfm. OV readings ranged from 1158 to 1401 ppm. Induced vacuum measured atthe extraction well (VW-3) was a constant 94 inches of water. • Based upon an effective vacuum potential of 0. 1 inches of water, the calculated effective radius of influence of SVE at the site will be approximately 28 feet (Figure 5). • TPH-g was detected in the soil gas/vapor samples at concentrations ranging from 8,700 pg/l to 10,000 µg/1. Benzene, toluene, ethylbenzene and total xylenes were detected in the gas/vapor samples at concentrations as high as 55 µg/1 benzene (In fluent 1240), 170 µg/1 toluene (In fluent 1440 and 1540), 87 µg/1 ethylbenzene (Influent 1240), and 310 µg/l total xylenes (Influent 1540). MTBE was detected at concentrations ranging between 120 µg/1 (Influent 1040) and 160 µg/1 (In fluent 1440). TPH-g, benzene, toluene, and MTBE were detected at concentrations above their respective MCLS. I 6.0. CONCLUSIONS Based on the ground water aquifer pumping test results, AGE concludes that groundwater extraction is not a feasible interim remediation option for removal of hydrocarbon-impacted ground water at the site. Based on the lack of# inferred radius of influence and the low transmissivity values, the site f Advanced CeoEnvironmental, Inc. f