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u i <br /> 20 February 2003 <br />' AGE-NC Project No 97-0290 <br /> Page 4 of 6 <br /> IBenzene was detected in ground water samples MW-2 and MW-4 at concentrations of 150 µg/l and <br /> 11 4g/l,respectively,xylenes was detected in samples MW-2 and MW-4 at a maximum concentration <br />' of 75 pg/l, and toluene and ethylbenzene and xylenes were detected in sample MW-2 at <br /> concentrations of 16 µg/l and 31 Mcg/l, respectively <br />' The fuel additive MTBE was detected in samples MW-2 and MW-4 at concentrations of 10 µg/l and <br /> 15 µg/l, respectively <br />' Petroleum hydrocarbons were not detected in the samples collected from wells MW-5 and MW-8 <br /> Analytical results of all water samples collected at the site are summarized on Tables 2 and 3 The <br /> laboratory report (CalTech ID No 0301-043-1 to -6), chain-of-custody forms and quality assurance <br />' and quality control (QA/QC) reports are included in Appendix B <br /> 3 3 ANALYTICAL RESULTS OF SOIL VAPOR SAMPLES <br /> The carbon-SVE unit operated continually,24 hours d day, during the observation period Extraction <br />'. flow rates were calculated to have been as high as 60 scfm An induced vacuum(negative pressure) <br /> of up to 20 inches of water was measured in the piping between the SVE blower and extraction wells <br /> (Table 4) <br /> H dl oc,arbon concentrations detected in soil-vapor samples collected on 28 Octo:,er 2002 were as <br /> Y p p <br /> I reported below <br /> • The influent soil-vapor sample contained detectable concentrations of TPH-g(1,600 gg/1)and <br /> the BTEX compounds benzene(2 4 µg/1),toluene(13 µg/l), ethylbenzene(4 0 µg/l) and total <br /> xylenes (49 µg11) <br /> • The effluent sample had detectable concentrations of TPH-g (2,100 µg/1) and the BTEX <br /> compounds benzene (5 8 [.g/1) and toluene (14 µg11) <br /> No additional target analytes were detected The analytical results are summarized on Table 2 The <br /> laboratory reports (MAI Sample Numbers for influent sample 0210508) Quality Assurance and <br /> Quality Control (QA/QC) reports and chain--of-custody forms are included in Appendix C <br /> 34 SOIL VAPOR EXTRACTION <br /> The carbon-based SVE system operated between 26 September and 28 October, during the quarter <br /> . The hydrocarbon mass (TPH-g) removed during the operating period was calculated using the <br /> Ifollowing equation <br /> Advanced GeoEnviranmental,Inc <br />