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5 <br /> AM � <br /> CLEARWATER <br /> G R O U P f ISI C <br /> • Eyrie —ai pilaf &micas <br /> That, while testing showed that limited contaminant migration had occurred, this movement <br /> was mostly restricted to the subject site A soil sample collected from boring SI-5 (drilled and <br /> sampled in October, 1993), located near the eastern site boundary, was shown to contain low <br /> levels of hydrocarbon contamination Concentrations were approximately half those measured <br /> in sample UGS, collected from soil immediately beneath the former unleaded UST <br /> Grab groundwater samples were collected by Kennedy/Jenks Consultants in March, 1995 <br /> Results of sample analysis confirmed that a limited fraction of fuel hydrocarbons had migrated <br /> beyond the property boundary As shown on the attached figure, concentrations attenuated <br /> significantly with distance from the former tank basin, with the extent of benzene dissolved in <br /> groundwater (above 1 ug/1) shown to be in the vicinity of SV-3/SV-4, approximately 100 feet <br /> from the former UST basin It should be noted that the Kennedy/Jenks sampling effort <br /> confirmed the presence of contamination in the vicinity of the nearby 7-11 convenience store <br /> The pattern of contaminant distribution in sampling points confirmed that this release was <br /> associated with the activities at this convenience store <br /> Concentrations of fuel hydrocarbons measured in groundwater samples collected from the <br /> monitoring wells installed during the earliest stage of investigation have been highest in the <br /> samples collected from MW-3 and MW-4 As you recall, these wells are located immediately <br /> adjacent to the former USTs It must be noted, however, that the measured concentrations in <br /> these wells declined significantly in the period immediately following the removal of the tanks <br /> and additional soil This decline in concentration cannot be attributed either to a significant <br /> change in water levels, as none had occurred, or to well-screen occlusion, as the water table <br /> was still intercepted by the screened interval at this time Well screens have been since <br /> submerged by rising water levels, but concentrations continued to decline during the period of <br /> slow water level advancement, documenting the positive effect of source removal at this site <br /> Concentrations over the course of the last two years have been below or near detectable levels <br /> Contemplated Future Activit <br /> Conversations most recently have involved consideration of an additional monitoring well <br /> downgradient of the former UST basin and existing monitoring wells It appears as if you feel <br /> closure is imminent, and the intended purpose of this additional well installation is to provide <br /> additional information required for your final closure analysis After reviewing the file, I believe <br />