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_f' .j ,1G _ <br /> AY, <br /> T <br /> Y <br /> The vertical extent of BTEX presence was not measured under the scope f th to study <br /> Because the gasoline components are generally less dense than water, <br /> hough some compounds <br /> innd to <br /> the groundwateear r column. As groundwater <br /> oted previously,sly, float ng product was ot fobe und inaved <br /> ny <br /> in the gra <br /> of the wells. <br /> 5.0 FINDINGS AND RECOMMENDATIONS <br /> 5.1 <br /> The following is a summary of the findings based on the field investigation, analytical <br /> results and interpretations: <br /> Four soil borings have been drilled by Kleinfelder on the site near the former <br /> underground fuel storage tank locations. Soil sample results indicate hydrocarbon <br /> residues are present in borings B-1 and B-2. <br /> Seven groundwater monitoring wells have been constructed on the site, three by <br /> Kleinfelder and four by WESTON. <br /> . The groundwater flow direction <br /> southwest <br /> utft/ftwest and south and the <br /> gradient magnitude ranges from 0 0037 to 0.0065 <br /> Soil samples from the capillary fringe zone in the WESTON monitoring well borings <br /> indicated the presence of minor concentrations of hydrocarbon residues in the <br /> borings constructed for wells MW-4, MW-5, MW-6 and MW 7. These residues <br /> apparently have no detectable impact on the groundwater in those wells. <br /> Hydrocarbon residues were found only in the groundwater sample from well MWA <br /> All of the other monitoring wells exhibited no detectable hydrocarbon presence. <br /> The extent of hydrocarbon presence in groundwater appears to be limited to an <br /> area surrounding well MW-1. <br /> 5.2 <br /> The soil and groundwater investigations at the EBMUD site to date have revealed minor <br /> amounts of hydrocarbon residues in soil and a detectable amount of residue in the <br /> groundwater centered over well Ir4W-1, No action is recommended for the minor <br /> hydrocarbon compound presencsoil <br /> hav ngtthe <br /> no impact on groundwater quaMt`y in <br /> locations as the compounds appear to be <br /> those wells. <br /> he-groundwater hydrocarbon presence appears to be relatively stable in that it has been <br /> present.in the same location (MW-1)-sEnce at-least-June--1989--The-seven.-monitorin <br /> wells on the site should be sampled and the water levels measured at least twice each <br /> - 15 - <br />