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.,�.. r. 0,PM-919- REGAL 605 8/16/91 :analysis. All wells tested negative (below detectors limits of 2 MDL/100ml) for Fecal Coliform but monitor wells MW2, MW4, rIW7 and 14146tested positive for Total Coliform at 1600 '.MN1100m1round indicating an active bio colony existing in and near the g water plume. A.b. GROUND WATER: JUNE 27, 1491 Sampling of the monitor wells occurred on June 27, 1991, and snowed similar results to the March, 1991 sampling. Reductions in benzene concentrations were noted in wells MW2, MW/ and MW8, while benzene concentrations increased in wells MW4, MW6 and MW9. Floating product sheen was still present in wells MW1, MW3 and MW10. Monitor wells MW2 and MW8 had moderate to strong bio odors, see Sampling Notes-Appendix B, and Table 1, Figures 5A and 5B. B. SOIL: As has been shown in the "Update Status Report, Flebri-,ary 23, 1990" sail contaminated with gasol4ne range hydrocarbons exists beneath the underground storage tank excavation from the 25 foot depth to top of ground water and at the 40 foot depth to top of ground water around monitor well MW10. The capillary fxinge area (50 foot depth) shows the spread of contaminant out to monitor wells MW1, MW2 and MW3, see Figure 6B. C. VAPOR: As has been stated above Foil contaminaticn e).ists from beneath the tank excavation to the top of the ground water. Overexcavation during the intial tank removal, removed contaminated soil to the 25 foot depth. Prior to replacement of the new double contained fiberglass tanks and dispensing system, 4 inch and 6 inch SCH 40 PVC 0.02 inch slotted pipes were placed vertically at the north corner and west corner of the excavation respectively and manifolded via underground to the treatment compound with SCH 40 2 inch and 4 inch PVC pipe. These pipes are to be used for vapor extraction - soil re:aiediation. WEGE will utilize monitor well MW10 along with the 4 and 6 Lach risers that have been placed '.n t%e tank excavation for soil vapor extraction. Also monitor wells MW1, MW2 and MW3 will be adapted so they may also be utilized for vapor recovery if warranted. Monitor well Mw10 has been connected to the treatment compound with 2 inch SCH 40 PVC pipe running beneath the surface. A needle valve with a sample port will connect this pipe to the steel manifold (vapor extraction manifold) that hooks into the blower to be used for vapor extraction, see Figure 7A and 7B. Also needle PAGE 7