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I 01 July 2008 AGE-NC Project No. 97-0301 Page 3 of 8 volatile aromatic compounds (benzene, toluene, 5hylbenzene and xylenes: BTEX), methyl tertiary— butyl ether (MTBE), t-amyl methyl ether (TAME), di-isopropyl ether (DIPE),7and 1 ,2-dichloroethane (1,2-DCA). P)J, or l' 2.3 . INSTALLATION OF REMEDIATION WELLS Based on recent quarterly ground water/monitoring events performed at the site, depth to ground water was generally measured at 27 feet below surface grade (bsg). Currently, wells MW-6 and MW-7 (screened 20 to 40 feet) are each partially screened through the vadose zone and are locate somewhat near the-'the gasoline-impacted soil core area at the site; AGE anticipates utilizing wells MW-6 and MW-7 as observation wells during the SVE pilot test. -Forms°° Significant gasoline-impacted soil extends vertically beneath the exr 11STSand fuel dispenser areas to depths of at least 40 feet bsg, and has spread laterally towards the east-northeast at least 55 feet (Figures 3 through 6). Therefore, to estimate the feasability of soil vapor extraction in the vadose S ' a zone, AGE is proposing to install three SVE wells to total depths of 30 feet bsg (just below the '�Y , vV approximate ground water level); wells will be installed in the following locations in anticipation of each well being included within a future SVE remediation network: • A four-inch diameter SVE well (VW4), screened between 10 and 30 feet bsg, will be located approximately 15 to 25 feet south of monitoring well MW- 1 . • A four-inch diameter SVE well (VW-2), screened between 10 and 30 feet bsg, will be located approximately 5 to 15 feet east-southeast of monitoring well MW- 1 . • A four-inch diameter SVE well (VW-3), screened between 10 and 30 feet bsg, will be located approximately 30 to 40 feet southeast of monitoring well MW Proposed SVE well locations are depicted in Figure 2; the lateral extent of gasoline-impacted soil �is depicted in Figure 3 , respectively; general lithology and the estimated vertical extent of gasoline-minpact to-soil-beneath-the--siteF-is-depicted-in-cross-sectional-views-E=E'and-FF'-o��, Figures 5 and 6, respectively. The proposed SVE screen intervals are located in areas of known soil gasoline-impact. Procedures for well installation are presented in Section 3 .2 . Initially, soil borings/SVE wells VW- 1 , V W-2 and VW-3 will be advanced to depths of 30 feet bsg, however, total depths of each borings and/or screen intervals may be adjusted in the field and will be based on field observations and field screening using an organic vapor monitor (OVM) equipped with a photo ionization detector with a 10.3 ev map (PID) capable of measuring volatile organic compounds. Soil samples will be collected at five-foot intervals beginning at a depth of 10 feet bsg to the total depth of the pilot borings; howev i soil samples are 01 roposed for laboratory Advanced GeoEnvironmental, Inc.