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,n v ga a Julian Munoz WEJSSpSSOC1ATE'S - 15 October 1987 Results of the OVA survey and odors noted by the field geologist are presented in Table 1. Seventeen soil samples were collected from the three boreholes for possible laboratory chemical analysis. The sample results are reported in the rightmost four columns of Table 1. Ten of the samples were submitted to BSC for analysis by gas chromatography/flame innization detection (GC/FID) for TFIIC and benzene, toluene and xylenes (BTX). BSC analytic results for all Phase II soil samples were below the detection limits of 10 parts per million (ppm) for TFHC and 0.5 ppm for BTX. Laboratory analytic reports for these samples are presented in Attachment C. To indicate soil quality near the water table, saturated soil samples from the fine-grained sediments found immediately below the water table were collected from the three borings and analyzed by GC/FID for TFHC. Since the GC/FID analytic technique for soil detects VOCs absorbed onto soil grains and contained in the pore water, analysis of saturated soil samples indicates total VOCs contained in the samples. Analysis of saturated soil cannot be used to precisely predict ground water quality, although it does provide a qualitative assessment of ground water and soil quality in the vicinity of the soil sample. r Subsurface Conditions There is good geologic correlation between wells and borings, as shown in the two geologic cross-sections constructed for this investigation. Locations of the sections are shown on Figure 2. OVA readings and laboratory analytic results are included on the cross-sections to show the vertical and horizontal extent of hydrocarbons beneath the site. From ground surface to a depth of 23 to 26 ft, soils consist of silty clays and clayey silts of low estimated permeability with occasional thin interbeds of clayey and silty sand of moderate estimated permeability. A unit of moderate to high estimated permeability consisting of clean sand and silty -- - g..-.. th of _. sand underlies these--fine=grained----sediments,-:-extendin to. a ....---. ep__ _ approximately 33 ft below grade. Ground water beneath the site occurs at a depth of approximately 18 ft below grade.