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5.0 CONCLUSIONS <br /> Groundwater elevations recorded during the.Third Quarter 2004 sampling were an average 0.58 feet <br /> dower than those recorded during the Second Quarter 2004.sampling; and the groundwater elevations <br /> recorded in the Fourth Quarter 2004 were 0.86 feet lower than those recorded during the Third <br /> Quarter 2004. <br /> r <br /> Contaminant-concentrations in groundwater at the Site have decreased significantly. It is apparent <br /> that the remedial systems are effective at removing contaminant mass from groundwater. Residual. <br /> contaminants in groundwater in the Fourth.Quarter 2004 .that exceed the respective Maximum - <br /> Contaminant Limits (MCLS) are limited to wells'MW-5 and MW-7, with free-product observed in <br /> well MW-3. Wells MW-5 and MW-7 are offsite and downgradient of well MW-3. The contaminants <br /> of concern are benzene (MW-5 at 48 ug/l and MW-7 at.3.6 ug/l) and MTBE (MW-5 at 15 ug/l and <br /> MW-7 at 3.5 ug/l). <br /> During the evaluation of the Third Quarter 2004:data, errors in the spreadsheet calculations for <br /> hydrocarbon mass removed were discovered. Upon closer examination of each equation used in the <br /> various tables, other errors that dated back.to September 2002 were discovered. The correction of the <br /> errors revealed that significantly more petroleum hydrocarbons have been removed by the SVE <br /> system than had been previously stated. The revised calculations indicate that through December 2, <br /> 2004, the SVE system has removed approximately 17,453 pounds of TPHg, 383 pounds of benzene <br /> and 8 pounds of MTBE. The SVE system continues to remove contaminant mass from the vadose <br /> zone at an average rate for the reporting.period of 5.8 pounds per day. <br /> �1 <br /> Cl <br /> S <br /> Project No.58643-06-01 -I l- December 30,2004 <br /> i <br />