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30 August 2004 <br /> AGE-NC Project No 99-0592 <br /> Page 10 of 13 <br /> 53 LABORATORY RESULTS OF GRAB GROUND WATER AND SOIL SAMPLES <br /> A total of three `grab' ground water and two soil samples were collected from the CPT soil boring <br /> and submitted for_laboratory analysis for the constituents listed in Section 4 2 No analytes of <br /> concern were detected in the samples submitted The laboratory report (CTEL Project I D <br /> CT214-0404062)quality assurance and quality control(QA/QC)report and chain of custody forms <br /> I are included in Appendix E Analytical results of the CPT samples are summarized in <br /> Tables 5 and 6 Results are also shown in cross section A-A' (Figure ) GeoTracker confirmation <br /> pages of the submitted laboratory EDF files are included in Appendix B <br /> 5 4 . SOIL MASS-VOLUME CALCULATIONS <br /> Figure 1 I depicts selected soil sample locations and the estimated extent of TPH-g concentrations <br /> adsorbed in soil in cross-sectional view, Figure 12 depicts the estimated lateral extent of TPH-g- <br /> Iimpacted soil adsorbed in soil in plan view Five concentration zones were estimated for this <br /> calculation,A half sphere formula and A�19,§5_0_M;Nj <br /> sed to estimate the volume of impacted soil <br /> Average concentrations (inner to outer ,�5 0 rn/kj,550 mg/kg, 55 mg/kg and <br /> 5 5 mg/kg',vere used to calculate the total volume of remaining hydrocarbons`m impacted soil_ ens <br /> the data collected at the site is plotted in both plan view and cross sectional views, the apparent <br /> I volume of the petroleum hydrocarbon-impacted area encompasses approximately 14,907 cubic feet <br /> and yields approximately 279 8 gallons of gasoline,which is equivalent to 1,749 pounds of gasoline <br /> Mass-volume calculations are shown in Appendix F Figures 11 and 12 show the iso-concentration <br /> lines used in the mass-volume calculations y� <br /> 6.0. SITE CONCEPTUAL MODEL <br /> Based on the data collected to date from soil and CPT borings and ground water monitoring wells, <br /> AGE has developed a site conceptual model for the release, migration and distribution of the <br /> contaminants in the subsurface as described below <br /> Release/s of 'petroleum hydrocarbons occurred from the on-site USTs Once released to the <br /> subsurface,the contaminants migrated into the upper clayey soil to a vertical depth of approximately <br /> 40 feet bsg (MWI-40), target analytes were not detected above laboratory reporting limits in soil <br /> Isamples collected from soil boring B-I (former UST location) at 50, 60 and 64 feet bsg Laterally, <br /> hydrocarbon-impacted soil is defined to the west by soil boring B-2, to the northwest by B-3, to the <br /> south by boring MW-Y",'and the northeast by boring B-4 Volumetric calculations indicate TPH-g in <br /> I soil is approximately 279 8 gallons (1,749 pounds) 1\ 4 t,D%\,5 <br /> \,5 <br /> k <br /> 't�A vanced GeoEnvironmental,Inc <br /> Wt A, Cut s <br /> J� <br /> i <br />