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24 October 2005 <br /> AGE-NC Project No. 98-0500 <br /> Page 4 of 11 <br /> Hydrocarbon concentrations detected in influent soil-vapor samples were as follows: <br /> • 28 July: TPH-g was detected at 660 micrograms per liter (µg/1); toluene at 24 gg/l; <br /> ethylbenzene at 7.1 µg/1 and total xylenes at 41 µg/1. <br /> • 18 August: TPH-g was detected at 1,400 µg/1; benzene at 6.5 gg/l; toluene at 35 gg/l; <br /> ethylbenzene at 3.6 µg/1 and total xylenes at 53 gg/l. <br /> • 12 September: TPH-g was detected at 730 gg/l; benzene at 16 gg/l; toluene at 38 gg/l; <br /> ethylbenzene at 15 gg/l and total xylenes at 130 µg/1. <br /> The hydrocarbon concentration measured in influent stream samples during the third quarter 2005 <br /> decreased and then increased during the mid to later portion of the quarter. Hydrocarbon <br /> concentrations measured in samples from the effluent stream in third quarter 2005 indicated a greater <br /> than 98 percent;rate of destruction; the destruction efficiency of the S VE unit was acceptable over <br /> the remediation period. The analytical results are summarized in Table 2. The laboratory reports <br /> (CTEL 0507190, 0508129 and 0509093) quality assurance/quality control (QA/QC) reports and <br /> chain of custody,forms are included in Appendix B. <br /> 2.3. MASS OF RECOVERED HYDROCARBONS <br /> The hydrocarbon mass (TPH-g) removed during the operating period was calculated using the <br /> following equation: M = C•Q•t <br /> where: M=cumulative mass recovered(kg) <br /> C = soil-vapor concentration(kg/m') <br /> Q = extraction flow rate (m'/hr) <br /> t=operational period, in hours <br /> The mass of hydrocarbons removed was based on analysis of soil-vapor samples. The mass of <br /> extracted hydrocarbons was calculated using average hydrocarbon concentrations of influent soil- <br /> vapor sample data and average air flow rates.A total mass of 1,667 pounds(lbs)of TPH as gasoline, <br /> or equivalent to a total volume of 266 gallons of TPH as gasoline were removed between 14 June <br /> and 12 September 2005.The volume-mass calculations and SVE unit performance table are provided <br /> in Appendix C. <br /> Advanced GeoEnvironmental,Inc. <br />