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' 14 April 2006 . AGE-NC Project No 95-0184 Page 4 of 5 approximately 28 5 feet southeast of the extraction point The maximum vacuum measured at the ' observation.points during the pilot test was plotted versus the distance from the extraction well �L (Appendix),) The effective radius of influence for each phase of the test was determined by drawing a best-fit line tHough these data points to correlate distance to vacuum data At a vacuum potential of 0 1 inches of water, the radii of influence are approximately 23 6 and 22 4 feet for phase I and phase II, respectively, at an induced vacuum potential of 1 0 inches of water,the radii of influence t are approximately 15 4 and 14 3 feet,respectively, at 10 0 inches of water the radii of influence are approximately 7 2 and 6 1 feet, respectively i ' Based on the United States Environmental Protection Agency (EPA)-prepared document, How to Evaluate Alternative Cleanup Technologies For UST Sates the radius of influence is considered to be the distance from the extraction well at which a vacuum of at least 0 1 inches of water is ' observed Based upon an effective vacuum potential of 0 1 inches of water,the calculated effective radius of influence utilizing well VW-5A at the site will be approximately 23 6 feet,utilizing VW-5B it will be approximately 22 4 feet Figure 4 depicts the effective radii of influence A ' calculation of the radius of influence is depicted in Appendix C ' • 4.0. SUMMARY AND CONCLUSIONS ' Based on the findings from this investigation, AGE concludes • On 17 January 2006, an 8 hour Soil Vapor Extraction Pilot Test was conducted at the site ' During phase I of the test (duration - 4 hours) vapor well V W-5A�was utilized as the extraction well, during phase II (duration - 4 hours) vapor well VW-5B was utilized • The SVE unit was operated at approximately 2,000 RPMs for the eight-hour test Flow rates ' were measured between 35 cfm and 90 scfm for the eight-hour test, averaging,significantly higher during phase I of the test "OV readings ranged from 306 to 772 ppmv Induced ' vacuum measured at the extractio wells ran ed from 42 to 100 inches of water 02V w 5h i-v -ta • During Phase I,TPH-g was detected in the inrfluent vapor samples at concentrations ranging from 13,000 µg/1 to 17,000 µg/1 Benzene, toluene, ethylbenzene and total xylenes were ' detected in the gas/vapor samples at concentrations as high as 13 µg/l benzene, 200 µg11 toluene, 300 p.g/l ethylbenzene and 1,560 µg/1 total xylenes During Phase II, TPH-g was detected in the inf uent vapor samples at concentrations ranging from 12,000µg/1 to 57,000 ' µg/1 Benzene, toluene, ethylbenzene and total xylenes were detected in the gas/vapor samples at concentrations as high as 280 pg/l benzene, 3,500 p,g/l toluene, 600 µg/1 ethylbenzene and 2,570 �ig/l total xylenes No other analytes were detected at or above ' laboratory reporting limits in any of the vapor samples Analytical results of the gas/vapor . samples are included in Table 2 Laboratory data for the soil gas/vapor data is included in Advanced GeoEnwronmental,Inc 1