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31 October 2003 <br /> AGE-NC Project No 95-0173 <br /> Page 6 of 8 <br /> Analytical results of SVE air samples are summarized In Table 5 The laboratory reports <br /> (MeCampbell Analytical Inc work order nos 0304271,0305252 and 0306494)and chain-of-custody <br /> forms are presented in Appendix D A plot of laboratory analysis of SVE influent TPH-g air stream <br /> concentrations versus time is included with Appendix E <br /> 45 MASS CALCULATION OF RECOVERED PRODUCT <br /> The hydrocarbon mass removed during the SVE operating penod was calculated using the equation <br /> M = C•Q•t <br /> where M =cumulative mass recovered (kg) <br /> C =vapor concentration (kg/m') <br /> Q = extraction flow rate (m'/hr) <br /> t= operational period, in hours <br /> Between 20 March 2003 and 23 June 2003, the SVE unit operated a total of 1,767 hours (Table 6) <br /> The average analytical results (approximately 144 pg/1) of the influent SVE air flow samples <br /> (Table 5), average flow rates (approximately 105 scfm, Table 6) and the operational period <br /> (1,767 hours)were used to calculate the approximate mass of extracted gasoline during this period <br /> During the March 2003 through June 2003 period, the mass of hydrocarbons extracted by the SVE <br /> system was calculated to be approximately 100 pounds, or equivalent to a volume of 16 gallons of <br /> gasoline Added to the estimated 1,591 gallons of hydrocarbons extracted from the SVE system since <br /> 1 I April 2000 (start-up), the total volume of hydrocarbons extracted to date is estimated at 1,607 <br /> gallons (Table 7) A plot of the cumulative volume (gallons) of hydrocarbons extracted to date is <br /> included with Appendix E The volume/mass calculations for extracted hydrocarbons are included <br /> with Appendix F <br /> 5.0. CONCLUSIONS <br /> The implications from the June 2003 ground water monitoring event are as follows <br /> • Ground water flow direction at the site was generally oriented east across the site at a <br /> gradient of 0 002 ft/ft or less Due to the generally low gradient at the site, slight variations <br /> in ground water measurements or changes of recharge/discharge of the local ground water <br /> could greatly modify ground water flow direction <br /> • The decrease of ground water elevation of approximately 0 10 feet between April 2003 and <br /> . the June 2003 monitoring events is probably due to seasonal fluctuation <br /> Advanced GeoEnvironmentai,Inc <br />