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�l <br /> Mr Lawrence H Beasley Project 22 611-100 001 <br /> . duly 18, 1997 <br /> Page 4 <br /> X 10-6 and a dry density ranging from 85 7 pounds per cubic feet (lbs/ft') to 97 5 lbs/ft3 <br /> Results of soil samples analyzed for permeability, moisture content, and dry density are <br /> presented in Table 3 <br /> LOCAL GEOLOGY <br /> Sediments underlying the site consist pnmartly of clayey silt to silty sand and fine- to <br /> coarse-grained sand The sedimentary units are generally laterally continuous From the <br /> ground surface to approximately 20 feet bgs, sediments consist of silty clay to clayey silt <br /> From approximately 20 to 38 feet bgs, sediments consist of silty sand to fine-grained <br /> sand From approximately 38 to 78 feet bgs (total depth explored) sediments consist of <br /> silt This unit includes a discontinuous layer consisting of fine-grained sand with an <br /> approximate thickness of 15 feet Geologic cross sections are shown on Figures 4 and 5 <br /> Surface trace of the cross section is shown on Figure 2 <br /> DISTRIBUTION AND REMOVAL OF PETROLEUM HYDROCARBONS <br /> !� The following section discusses the distribution of hydrocarbons in soil and groundwater <br /> In addition, the following section presents EMCON's estimated mass of petroleum <br /> hydrocarbons removed by excavation and SVE, estimated hydrocarbons mass prior to <br /> SVE, and estimated mass of hydrocarbon in soil and groundwater currently remaining <br /> beneath the site Due to the lack of intermediate data points in the vicinity of the former <br /> UST complex, EMCON's depiction of the distribution of hydrocarbons and the <br /> hydrocarbon mass prior to SVE and remaining beneath the site, is only an estimate <br /> Soil <br /> Based on analytical results of soil samples collected from beneath the former UST and <br /> from soli borings, residual hydrocarbons have been delineated The majority of the <br /> hydrocarbons were detected in the vicinity of the former UST The former 1,000-gallon <br /> UST cavity was excavated to approximately 10 feet bgs Analytical results of soil <br /> samples collected from beneath the UST and soil borings are presented in Table 4 <br /> Estimated Mass of Hydrocarbons Removed by Excavation _ <br /> TPHG was detected at the base of excavation at a concentration of 3,400 ppm Dunng <br /> excavation and overexcavation activities, approximately 12 cubic yards of soil were <br /> removed (324 cubic feet) The total pounds of hydrocarbons removed have been estimated <br /> assuming a bulk density of 97 5 lbs1W and using the actual concentration obtained from <br /> SACK 1261 ICLQS URE-951dms 1 <br />