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CONCLUSIONS <br /> Based on the data presented in this report, soils adjacent to the underground tanks contain the <br /> highest concentration of hydrocarbon beneath the site Three vapor wells are located in this <br /> general area and can be used to access the soil for vapor monitoring or vapor extraction, if <br /> necessary Based on the analytical data, well VWC is expected to contain the highest volatile <br /> load of these wells Figure 6 shows the distribution of hydrocarbon in soil at each well point <br /> Groundwater beneath the site currently occurs at about 48 feet below grade in an unconfined <br /> condition Wells MW2 and MW3 have significant dissolved hydrocarbon concentrations, and <br /> wells MW1 and MW4 have less than detectable benzene concentrations New wells MW8 and <br /> MW7 have significant hydrocarbon levels which is interesting since neither well is located near <br /> a suspected source of contamination Also, data from well MW4 suggests these hydrocarbon <br /> levels may be derived from separate source areas, since it contains less than detectable <br /> hydrocarbon levels and is located between the two points (Figure 5) Additional sampling from <br /> these wells is recommended to determine if the levels measured in the new wells is consistent <br /> over time <br /> The remaining proposed wells (MW5 and MW6) which were originally proposed for installation <br /> in off-site locations on Rivara Road and across Pacific Avenue should be re-evaluated Proposed <br /> well MW5 (on Rivara Road) would not appear to aid in definition of the plume given the low <br /> or less than detectable levels found in well MW 1 If future sampling events show that the data <br /> from MW8 and MW7 is consistent over time Well MW5 should be moved to a location <br /> upgradient (west) of MW8 or downgradient (east, on Pacific Avenue) of MW7 Further analysis <br /> of the groundwater data over time should be used to establish the location of this well <br /> Page 10 <br />