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26 December 2001 ' AGE-NC Project No 97-0290 Page 5 of 8 1 Benzene was detected in ground water samples collected from wells MW-2, MW-4, MW-6 and MW-7 at maximum concentrations of 1,400,ugll, 130µg/], 13 µg/1 and 1 0 ug/l, respectively Other BTEX compounds were detected in wells MW-2 and MW-4 at maximum concentrations of 830µg/1 ' (xylene MW-2) Petroleum hydrocarbons were not detected in the samples collected from wells MW-1, MW-3 and MW-8 ' Analytical results of all water samples collected at the site are summarized on Tables 2 and 3 The laboratory report (MAI Lab ID No 60873 to 60879), chain-of-custody forms and quality assurance and quality control (QA/QC) reports are included in Appendix B 3 3 SOIL-VAPOR EXTRACTION ' The thermal SVE tout operated at varying rates during the observation period Extraction flaw rates ' were calculated to heave been as high as 60 scfm An induced vacuum (negative pressure) of up to 30 inches of water was measured in the piping between the SVE thermal blower and extraction wells (Tables 4) lie The thermal SVE unit operated adequately over the quarter, however the overall operational capacity of the unit was limited due to either low oxygen content anal/or high carbon dioxide levels in the influent soil-vapor Several re-starts were preformed over the time period The carbon-based SVE operated continually, 24 hours a day, at a maximum 50 scfm during March and April An induced vacuum of up to 22 inches of water was measured in the piping between the SVE blower and extraction wells (Tables 4) The system was non-operational during repairs or time where an excessive discharge would have occurred Hydrocarbon concentrations detected in influent soil-vapor were as samples reported below p • 21 December 2000 TPH-g was detected at 21,000 µg/1, benzene at 42µg/1 toluene at 180 1,,6g/1, ethylbenzene at 68 ,ug/1 and total xylenes at 380µg11 • 23 January 2001 TPH-g was detected at 15,000µg/1, benzene at 34µg/1, toluene at 140 4g/1, ethylbenzene at 77 µg/1 and total xylenes at 470µg11 • 21 February2001 TPH-g was detected at 15,000µgll,benzene at 21µg/l toluene at 100µg11, ethylbenzene at 64 µg/1 and total xylenes at 360µg/1 • 19 March 2001 TPH-g was detected at 6,200 µg/1, benzene at 8 5µg/1 toluene at 42 40, ethylbenzene at 32 µg/1 and total xylenes at 210 4g/1 • 05 April 2001 TPH-g was detected at 6,800 µg11, benzene at 12 µg/1 toluene at 41 µg/1, Iethylbenzene at 24 µg11 and total xylenes at 220 4g11 Advanced GeoEnviron mental,Inc