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I11 August.1999 <br /> M AGE-NC Project4No.'95-0109 . i <br /> Page 3`of 10: <br /> 2:5: LABORATORY'ANALYSIS <br /> Selected soil samples were analyzed for: <br /> I ,Total .petroleum. hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Methods-5030/8015m;and <br /> • Volatile aromatics (benzene; toluene, ethylbenzene and xylenes: BTEX) with methyl tert- ' <br /> , . . . <br /> butyl ether(MTBE)'in accordance with EPA method 8020/602. <br /> Four soil samples were transported to A. Keith Kaufman. in. Culver 'City and analyzed for <br /> I physicochemical properties and microbiological enumeration. <br /> 2.6. PREPARATION OF CROSS SECTIONS <br />' Atotal'of 14 cross sections were.prepared for-the site illustrating hydrocarbons concentrations in <br /> soil. In addition, three cross sections illustrating,the shallow subsurface geology, prepared for the <br /> Quarterly Report.- December-1998 are presented-again. For•each of the three lines of cross`section, <br /> paired figures illustrate the extent of impacted^soil before treatment (October 1993) and treatment <br /> progress as of February 1999: The.cross sections are included as,Figures 9 to,17. <br /> ma <br /> Eight subsurface s were alire ared to illustrate the lateral extent of impacted soil at various <br /> g p _ so pp <br /> depth intervals. Subsurface maps were prepared for four.depth intervals. for,October 1993 and <br /> February,-1999, (Figures-5a to.8b). The extent of impacted.soil in.February 1999 was'based on, _ <br />' borin h P27; advanced Between February 1994.and Februa <br /> s <br /> g , P1• through ' <br /> ry 1999.. The .extent'of <br /> impacted soil 'in. October •1993 was .based on' all. previous data. Additionally,•where higher <br /> concentrations'of hydrocarbons were detected- in borings P1 through P27, the impacted soil. was <br /> assumed.to be present in October 1993. <br /> 2:7. MASS BALANCE CALCULATIONS 1 <br />' . The cross ,sections' and maps 'described in =Section 2:6: were used to estimate the, mass of <br /> contaminants at the site prior to initiation of remediation iri October 1993 and remaining at the site <br />' as of February.1999. ,The areas pf impacted'soil'were estimated as illustrated in`Figures 5a to 8b. <br /> Are'aswith impacted soil greater than 1;000 ppm were calculated'separately from areas with less than <br /> 1,000.ppm. The average thickness of each layer was then estimated from the cross sections (Figures <br /> 9 to 17) 'and the volume and mass of each section calculated. An average concentration of TPH-g <br />' was estimated from''soil samples collected and the mass of contaminant calculated. <br /> Aihanced CeoEnvironmentai,Inc. <br />