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'Ff <br /> 06 August 2000 <br /> _ =f AGE Project No. 95-0118 <br /> Page 3 of 5 <br /> TPH-g was detected in the 07 February, 23 April, 31 May and 28 June 2000 samples collected from <br /> influent vapor stream at concentrations of 1,000 micrograms per liter(,ug/l), 430yg11; 300 µg11 and <br /> 450µg11, respectively. BTE&X were detected at concentrations as high as 92 µg/1 of xylene on 23 <br /> _ April 2000. MTBE was not detected in those samples. <br /> The analytical results are summarized on Table 3. The laboratory report (MAI 30552, 30553, 36318, <br /> k 36319, 39101, 39102, 41659, 41660), Quality Assurance and Quality Control (QA/QC) reports and <br /> chain-of-custody forms are included in Appendix B. <br /> Comparison of organic vapor readings using the PID between influent and effluent vapor streams <br /> indicated a destruction rate of 85 to 90%. However,using the analytical results, a greater destruction <br /> rate could be demonstrated. <br /> 3.2. MASS OF RECOVERED HYDROCARBONS <br /> i <br /> The hydrocarbon mass removed during the operating period was calculated using the following <br /> equation: M = C•Q•t <br /> where: M= cumulative mass recovered(kg) <br /> C = vapor concentration (kg/m}) <br /> Q — extraction flow rate (m3/hr) <br /> t— operational period, in hours <br /> The operational time was divided into four time periods. The mass of extracted Hydrocarbons was <br /> calculated for each time periods using the average hydrocarbon concentrations of influent vapor <br /> i samples collected and average flow rates. A total of approximately 15 gallons of gasoline were <br /> calculated to have been removed between January and June 2000.The mass calculations are attached <br /> in Appendix C. <br /> 3.3. RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> } The relative ground water elevation in each well was calculated by subtracting the ground water <br /> depth from the surveyed casing elevations. The depth to ground water and the relative ground water <br /> elevations are summarized in Table 1. <br /> During the first quarter sampling event,the depth to ground water, as measured from the casing tops, <br /> ranged from 32.49 feet to 3 3.8 8 feet. The average relative ground water elevation decreased 2.94 feet <br /> for the second quarter. <br /> Advanced GeoEnvironmental,Inc. <br />