Laserfiche WebLink
r � <br /> Mr Kyle Christie Project 20805-144 004 <br /> July 26, 1996 <br /> Page 3 <br /> • Six to 14 feet bgs for evaluation of impacts related to the piping trenches and <br /> UST complex Soil type generally consists of sand to silty sand with some <br /> interbedded silt, silt predominates beneath the piping trenches at this depth <br /> interval <br /> Fourteen to 20 feet bgs for evaluation of UST complex impacts Soil type <br /> generally consists of interbedded sand, silty sand, and silt <br /> • Twenty to 35 feet bgs for evaluation of the vertical extent of impacts Soil type <br /> generally consist of fine to coarse grained sand with interbedded silty sand and <br /> silt <br /> The area enclosed within each isoconcentration line was determined using a planimeter <br /> and the volume was determined by multiplying the area by the thickness of the soil zone <br /> Tsoconcentration maps are shown on Figures 3 through 6 <br /> In order to simplify the calculations, the following assumptions were made <br /> • • TPHG concentrations within a given interval remained constant using the <br /> isoconcentration line value <br /> a the isoconcentration line location did not vary with depth within a given interval <br /> soil type and bulk density remained constant with a given interval <br /> The mass of TPHG was calculated as follows <br /> Mass TPHG(lb) Vol of TPHG X soil density (lb/ft) X TPHG <br /> impacted soil (ft) concentration <br /> (ppm) <br /> The estimated petroleum hydrocarbon mass (TPHG) using 1992 analytical results is <br /> 735 pounds The breakdown by soil interval is summarized below The calculations are <br /> presented in Appendix C <br /> i <br /> SACK\08051440 Doc-96Wms i <br />