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10 September 2004 AGE-NC Project No 03-1100 Page 8 of 10 41 SOIL DESCRIPTIONS Sandy silt, clayey silt and silt with an orange brown to grey brown color was generally encountered from surface grade to total depth of each boring Silty sand was encountered at 30 feet and 45 feet bsg,and medium-to fine-grained sand was identified below 54 feet bsg in boring OZ2 Grey brown sandy and silty clays were encountered between 30 and 35 feet bsg in boring SVE2 and between 40 and 55 feet bsg in borings OZ1 and OZ2 Grey hydrocarbon stained clay was encountered in boring OZland OZ2 at 50 feet bsg Soil boring logs are depicted in Appendix A 42 ANALYTICAL RESULTS OF SOIL SAMPLES A total of four soil samples were analyzed for the constituents listed in Section 3 1 2 No analytes of concern were detected in any of the analyzed samples Analytical results of the soil samples are summarized in Table 2 The laboratory report (CTEL Project No CT214-0312147), quality assurance and quality control (QA/QC) report and chain of custody are included in Appendix B 43 SOIL VAPOR EXTRACTION PILOT TEST RESULTS During the pilot tests on 27 and 28 January 2004,the SVE unit was operated at 1,950 to 2,375 RPM, gas flow rate ranged between 40 and 60 cfin (standard cubic feet per minute), and OV readings ranged between 400 and 2,280 ppm(Table 4) The induced vacuum measured at the extraction wells ranged from 14 to 33 inches of water During the shallow SVE pilot test (27 January 2004), the greatest induced vacuum was measured in observation well SVE2, located nearest extraction well SVE1, at 2 5 inches of water, the lowest vacuum was measured in SVE3, approximately 20 feet south of the extraction well and screened at the strati graphically equivalent interval During the deeper SVE pilot test(28 January 2004), the greatest induced vacuum was measured in observation well SVE1, located nearest extraction well SVE2, at 3 8 inches of water The lowest - - vacuum was measured in SVE3, approximately 20 feet south of the extraction well and screened at a stratigraphically higher interval Sufficient vacuum was measured in the observation wells to indicate that a vertical connection may exist across stratigraphic layers at the site AGE determined the effective SVE radius of influence by plotting the maximum vacuum measured at the observation wells during pilot testing versus the distance from the extraction well on a logarithmic scale(Appendix C),the effective radius of influence was determined by drawing a best- ,10 fit line though these data points At a vacuum pressure of 0 10 inches of water, the radius of Advanced GcoEnvironmental,Inc