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i I29 December 2004 AGE-NC Project No 95-0130 IPage 9 of 10 • The volume of hydrocarbons extracted by the SVE system was calculated to be approximately 573 gallons (equivalent to 3,578 pounds) of petroleum hydrocarbons (Appendix F) between the 31 August and 01 October 2004 monitoring periods (Table 7) I 5.0. RECOMMENDATIONS Based upon the results of the Third Quarter 2004 Investigation, AGE recommends • Continued quarterly ground water monitoring of wells VW-1 (B and C), VW-2A, VW-3A, MW-6(A-E)and MW-7(A-E) The Fourth Quarter 2004 ground water monitoring event was performed on 23 November 2004 Conduct future ground water monitoring events concurrently with the Knowles/Roek Property site (102 South Wilson Way) and the Arco AM/FM site (130 South Wilson Way), • In accordance with Interim Remediation Work Plan-May 2003,interim groundwater pump- and-treat (P-T) remediation was initiated at the site on 17 November 2004, start-up P-T remediation results are forthcoming and will be reported in Quarterly Report - Fourth Quarter 2004 • Continued quarterly depth-to-water measurements in all monitoring wells at the site, but reduced ground water sampling frequency from a quarterly to a semi-annual program, AGE believes that continued quarterly ground water sampling from these wells at this stage of the investigation is not cost effective and will not provide enough useful information to ' supplement the ongoing investigation Semi-annual sampling events should be adequate to monitor ground water impact at these wells and should be re-evaluated on a semi-annual basis • The most intense hydrocarbon-Impact was reported in the ground water samples collected from soil vapor extraction wells VW-1/2/3 with TPH-g as high as 180,000 µg/1,benzene as high as 60,000 µg/1 and MTBE as high as 2,300 µg/1 Furthermore, the site recently underwent building demolition, and the site is temporarily wide open with no building or surface obstructions Therefore,AGE recommends installing two-inch diameter pneumatic ground water pumps In VW-1C (48-63 feet),VW-2A(43-63 feet) and VW-3A(43-63 feet) to augment interim ground water remediation efforts, extracted ground water from wells VW-1 C,VW-2A and VW-3A would be routed to the existing ground water pump-and-treat ' system IAdvanced GeoEnvironmental,Inc