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29 January 2001 <br /> . AGE-NC Project No. 98-0450 <br />' Page 4 of 6 <br />' samples at concentrations ranging from 82µg11 in sample BMW-2 to 5,500,ug/1 in sample BMW-4. <br /> Benzene was detected in two samples at concentrations ranging from 1.5 ,ug/l in BMW-2 to 15 µg11 <br />' in sample MW-5. The remaining BTEX compounds were detected at various concentrations with <br /> the highest concentrations occurring in BMW-4 (1,900µg/l of total xylene). <br />' MTBE was detected in samples BMW-2, BMW-4 and MW-5 by EPA method 8260 Modified at <br /> concentrations ranging from 1.3 µg/l in sample BMW-4 to 280 µg/1 in BMW-2. <br />' The laboratory report (MCAT Laboratory I.D. No. 50100 to 50105), Quality Assurance and Quality <br /> Control Data(QA/QC) and chain-of-custody forms are presented in Appendix B. The results of the <br /> analyses are summarized in Tables 2 and 3. <br /> 3.3. SOIL-VAPOR EXTRACTION <br />' The SVE unit operated at varying rates during the observation period. Extraction flow rates were <br />' calculated to range from 190 to approximately 200 cfm. An induced vacuum (negative pressure) of <br /> approximately 24 to 28 inches of water was measured in the piping between the blower and <br /> extraction wells. <br /> Hydrocarbon concentrations detected in influent soil-vapor samples were as follows: <br />' 20 October 2000 - TPH-g was detected at 2,300 4g11; benzene not detected; toluene at 40 <br /> µg11; ethylbenzene at 14 µg11 and total xylene at 81 µg11. <br /> • 27 November 2000 -TPH-g was detected at 2,300µg11; benzene not detected, ethylbenzene <br /> ' at 19 µg/1, toluene at 33 ugll and total xylene at 130µg/1. <br /> The laboratory reports(MAI Sample Numbers: 51022, 51023, 54318 and 54319) Quality Assurance <br /> and Quality Control (QA/QC) reports and chain-of-custody forms are included in Appendix C. <br /> Hydrocarbon concentrations measured in samples from the effluent stream in October and November <br /> indicated a minimum 77 to 85 perdent rate of destruction. Concentrations of discharged organic <br /> vapor did not exceed the.APCD permitted daily 14.3 lbs of VOCs. The highest concentration of <br /> _,organic vapor measured with the OVM was 425 ppm. - <br /> ' Advanced GeoEnvirORmental,Inc. <br /> 1 <br />