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4.0 CONCLUSIONS AND RECOMMENDATIONS <br /> In sod, concentrations of TPH-as-gasoline, BTEX and MTBE were detected throughout the soil <br /> column Concentrations of gasoline compounds appear to exist throughout the unsaturated <br /> vadose zone soils, and within the capillary fringe and saturated soil intervals The highest <br /> concentrations were detected in the soil samples collected between 25 and 40 feet bgs from the <br /> well boring through the former UST Concentrations of gasoline compounds declined significantly <br /> at and below the groundwater table The lateral extent of impacted soil appears to be defined to <br /> l the vicinity of the former UST#3, and to the west at MW-6 The vertical extent of impacted sod is <br /> not defined at the total depth of investigation of 60 feet bgs <br /> In roundwater, gasoline hydrocarbons are concentrated as free product near former UST#3 and <br /> g , g Y p , <br /> dissolved concentrations of gasoline compounds decrease with distance from the source area <br /> As shown on Figures 5 and 6, the lateral extents of TPH-as-gasoline and benzene in groundwater <br /> appear to be fully defined As shown on Figure 7, the lateral extent of MTBE is mostly defined, <br /> ' except for low concentrations at MW-4 to the east and MW-7 to the west of the former UST <br /> source area The vertical extent of impacted groundwater has not been investigated <br /> The installation of the remedial feasibility test wells was completed so that remedial tests could be <br /> conducted The results of the remedial tests will be used to design a soil and groundwater <br /> remediation system at the site <br /> ' Based on these conclusions, Ramage Environmental recommends that the remedial feasibility <br /> tests be completed, and the vertical extent of impacted soil and groundwater be investigated, as <br /> soon as funding is available in the county facilities management budget In the meantime, <br /> quarterly groundwater monitoring and monthly free product removal should continue <br /> 1L <br />� L <br /> �s <br /> 13 <br />