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k{ 27 September 2007 AGE-NC Project No. 99-0682 Page 4 of 6 i 2.2. 1 . Upper Vadose SVE Pilot Test Sampling and Analysis � j A total of six soil vapor samples were collected during the pilot test. Vapor samples were collected at 2-hour intervals beginning at 0815 hr from the sample port at the extraction well VW-2 to measure hydrocarbon concentrations in the extracted soil vapor; one sample was collected at 1615 hr from an effluent port at the end of the pilot test. The samples were collected into Tedlar bags, transported in a container under chain of custody to CTEL, and analyzed within 72 hours for the constituents ` listed in Section 2. 1 . 1 . J 2.2 .2 . Analytical Results of Soil Vapor Samples - Upper Vadose IITPH-g was detected in the influent vapor samples collected from upper vadose vapor well VW-2 at J concentrations ranging from 4,600 µg/1 (0815 hr) to 11 ,000 µg!1 ( 1415 hr) . Toluene, ethylbenzene, _ and total xylenes were detected in the vapor samples at concentrations as high as 170 µg/1 toluene (1415 hr), 190 µg/1 ethylbenzene (1615 hr) and 720 µg/1 total xylenes (1615 hr). MTBE and benzene I- were not detected at or above the laboratory detection limits in all the samples analyzed. TPH-g and BTEX were detected in the effluent vapor sample collected at 1615 hr on 18 July 2007 at concentrations of 120 µg/1 TPH-g, 3 . 5 µg/1 toluene, 6. 1 µg/1 ethylbenzene and 1 I µg/1 xylenes. No additional constituents of concern were detected at or above laboratory detection limits in the vapor samples analyzed. Analytical results of soil vapor samples are summarized in Table 4. The laboratory report (CTEL Project No. CT214-0707149), QA/QC report, and chain of custody forms are included in Appendix B; the confirmation number for GeoTracker submittal of laboratory electronic deliverable format (EDF) is 3772436916. 2.2 .3 . Results of the Upper Vadose SVE Pilot Test The flow rate was measured between 40 scfm and 45 scfm for the 8-hour test. Influent organic vapor readings ranged from 560 ppm to 974 ppm. Induced vacuum measured at the extraction well (VW-2) was between 50 and 54 inches of water. As expected, the highest vacuum (0.25 inches of water) was measured in the upper vadose-screened observation point (VW-4), as well as the closest lower vadose-screened observation point (VW- 1 ). Vacuum measurements recorded from the other observation wells (VW-3 , MW4A, MW-3 , MW4 and MW-5) ranged from 0 to 0. 10 inches of water. As noted in the lower vadose SVE pilot test, observation well MW- IA, southwest of extraction well VW-2, did not record any change in vacuum throughout the test. Advanced GeoEnvironmental, Inc. Lll