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i a 9tENT Be-PORT andl oil Company 5726 Trney Boulevard,Tracy,California Dale.Proj*.&No.40-99-012 Pale 9 3.3 Monitoring WelUnIMULILM Three 4-inch-diameter monitoring wells were installed at the site (MW-1, MW-2, and MW-3)on September 15, 1989. Monitoring well locations are shown in Figure 2. The wells were constructed with Schedule 40 PVC riser pipe, 0.010 slot-size screen, m3 )Monterey sand filter pack, and scaled 4 with bentonite pellets and a cement bentonite grout. The three monitoring wells were screened from 7 to 22 feet. Construction details are presentee) in Appendix C. 3.4 5urvey of MgnitoJAP Wells On September 26, 1989, the monitoring well elevations were surveyed to determine the elevations i.y of the riser pipe and the adjacent ground surface with reference to a bench marl: with an assumed elevation of 100.0 feet. The bench mark was located on top of the sidewalk at the northeast corner of the station building (see Figure 2). s' a Welt i?evelonmcrA Monitoring wells MW-1,MW-2,and MW-3 were developed on September 26, 1989. Approximately sevenµell casing volumes of water were removed from each well. --_ u6 Spil (: etnistLy A total of 33 soil samples were collected from soil borings SB-1 through SB-4.:,B-7 through SB-11, 'r and monitoring wells MW-1 through MW-3. Each soil sample was screened for the presence of petroleum constituents using a portable PID equipped with a 10.2 eV lamp calibrated for benzene for direct reading in ppm. The PID indicated that no sample had a reading of greater than 10 ppm. One sample from each boring was submitted to the laboratory and analyzed for TPH and BTEX. Laboratory reports are presented in Appendix E. ¢.1 Prouose h w n Tanks Four soil borings were drilled within the area of the proposed underground storage tanks (SB-7 through SB-10). A total of four soil samples were collected at depths of I1 feet be:aw the ground surface and were sent to the laboratory for chemical analysis of BTEX and 7PH. Chemical results are summarized in Table 5 and Iaboratory data sheets are presented in Appendix E.