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between sampling/augering. Upon obtaining the soil sample the <br /> sleeve was withdrawn from the sample barrel and the uncovered ends <br /> were screened with the HNU-PID, then sealed with aluminum foil, <br /> Plastic end caps, then sealed with dLat tape, labeled, put into s <br /> zip lock freezer bag, and placed upon dry ice in a cooler for <br /> preservation. The chain of custody was filled out prior to <br /> leaving the site and the samples were hand delive. ee to ChemTech <br /> Laboratories (State of California Cert. # 359) . <br /> CONCLUSIONS <br /> The results of ground water monitoring, August 24, 1990, indicate <br /> that the ground water has dropped approximately eight feet since <br /> early January, 1990, and is flowing predominately to the <br /> southeast. Chemical results of the water samples taken from the <br /> monitor wells show contamination to the ground water with gasoline <br /> range hydrocarbons. <br /> Soil contamination as limited to below the 20 foot depth of the <br /> eastern and western portions of the pump island area and at the 30 <br /> foot depth southeast of the tank excavation. This Contamination <br /> is of gasoline range hydrocarbons. Soil contbLminated with aged <br /> gasoline hydrocarbons still exists at the 20 foot depth beneath <br /> the western and eastern pump island excavations and at the 30 foot <br /> depth southeast of the tank area excavation. <br /> RECOMMENDATIONS <br /> 1. Finish aeration of the excavated soil, and use this soil <br /> to back fill (appropriately compacted) the excavations to <br /> the surface. <br /> 2. Place three onsite vapor extraction wells; one each <br /> through the compacted back fill of the tank excavation, <br /> the compacted back fill of the eastern pump island area <br /> and the compacted back fill of the western pump island <br /> area into native soil to the 40 foot depth, see <br /> Figures 7A and 7C. <br /> 3. Manifold the vapor recovery wells to a common treatment <br /> facility near the dumpster area of the site, see Figure <br /> 7A. <br /> 4. Perform a vapor source - pilot test. <br /> b, Perform a cost/benefit for the best means to treat the <br /> vapors generated by a vapor recovery system based off of <br /> the pilot test. <br /> 5. Perform quarterly ground water monitoring. <br /> i 5 <br />