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21 May 2001 AGE-NC Project No 95-0173 Page 5 of 7 operational for 1,689 hours (Table 5) During the operational period, SVE inlet flow rates ranged ' from 54 to 110 cubic feet per minute (cfrn), differential pressures ranged between 10 and 4 0 inches of water, and induced vacuum between 15 and greater than 25 inches of water Utilizing a photo ionization meter (PID), hydrocarbon concentrations were measured between 22 and 255 parts per ' million (ppm) at regular intervals at the SVE inlet, however a general concentration trend was not established from the PID field measurements Field measurements are summarized in Table 5 ' 4 4 ANALYTICAL RESULTS OF SOIL-GAS VAPOR SAMPLES ' SVE air flow samples were collected on 24 January, 15 February and 15 March 2001 TPH-g was detected in all three influent SVE air flow samples at concentrations as high as 1,600,ug/1, TPH-g was detected from the 24 January 2001 effluent SVE air flow sample at a concentration of 370 kig/l ' BTEX compounds were detected in all three influent SVE air flow samples at concentrations as high as 150 ,ug/l (xylenes, 15 March 2001) Benzene was only detected in the 15 March 2001 influent tSVE air flow sample at a concentration of 0 93 ugll Analytical results of SVE air flow samples are summarized in Table 4 The laboratory reports(McCampbell Analytical Laboratory I D Nos 5 8687- 88, 60296-97 and 62935-36) and chain-of-custody forms are presented in Appendix D A plot of lie laboratory analysis influent TPH-g SVE air flow concentrations versus time is included with Appendix E 4 5 MASS CALCULATION OF RECOVERED PRODUCT ' The hydrocarbon mass removed during the SVE operating period was calculated using the following ' equation M= C•Q•t ' where M = cumulative mass recovered (kg) C =vapor concentration (kg/m') 1 Q = extraction flow rate (M3/hr) t =operational period, in hours Between 01 January 2001 and 31 March 2001 (first quarter 2001), the SVE unit operated a total of 1,689 hours (Table 5) The average analytical results (approximately 1,367µg/1) of the SVE air flow samples (Table 3), average flow rates (approximately 84 efin, Table 5) and the operational period ' were used to calculate the approximate mass of extracted gasoline during these periods During the first quarter 2001, the mass of hydrocarbons extracted from the SVE system was calculated to be approximately 726 5 pounds, or equivalent to a volume of 116 2 gallons of gasoline . Added to the estimated 613 gallons of hydrocarbons extracted from the SVE system since i 1 April Advanced GeoEnvironmental,Inc