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are located on the site and to prevent accidental dig in of facilities and to insure that all <br /> former UST's and their associated piping have been identified and removed <br /> It is currently planned that approximately 10 soil borings will be drilled both onsite and <br /> offsite to a depth of approximately 60 feet bgs (Figure 9) A tabulation of objectives of <br /> the soil borings and/or associated monitoring wells to be drilled is identified below <br /> Soil Boring/ Placement Rationale Total Depth (feet) <br /> Monitoring Well � <br /> SB-5 Tank Pit investigation 60 feet <br /> SB-6 Dispenser investigation 45 feet or Pt water <br /> SB-7 Dispenser investigation 45 feet or 15` water <br /> MW-4 Downgradient of Main Plume 60 feet <br /> MW-5 Downgradient of Main Plume 60 feet <br /> MW-6 Downgradient of Main Plume 60 feet <br /> MW-7 Cross-gradient of Main Plume 60 feet <br /> MW-8 Cross-(up) gradient of Main Plume 60 feet <br /> MW-9 Up gradient of Main Plume 60 feet <br /> MW-10 Cross-gradient of Main Plume 60 feet <br /> Soil samples will be collected from the soil samples every five feet It is anticipated that <br /> seven of these soil borings will be completed as 2" diameter monitoring wells (MW-4 to <br /> 10) The new monitoring wells (PT-MW-4 to 10) will be surveyed and tied to the local <br /> vertical datum in use for the greater Lodi Groundwater Area of Investigation <br /> Soil samples from the 10 soil borings will be screened with a Photo Ionization Device <br /> (PID) and it is anticipated that 5 to 7 samples from each boring will be analyzed by a state <br /> certified analytical laboratory It is anticipated that USEPA Test Method 8260B will be <br /> utilized to determine the concentrations of TPH-g, BTEX, 7 oxygenates, and lead <br /> scavengers (1,2-DCA and 1,2-EDB) The 8260B scan is warranted because of the <br /> unanticipated discovery of the presence of MTBE and 1,2-DCA at or above MCL's in <br /> monitoring well PT-MW-3 during the 1'` quarter 2003 monitoring event at the site <br /> Quarterly groundwater monitoring and sampling of the monitoring wells will be initiated <br /> A 72-hour pump test of monitoring well PT-MW-3 will be conducted to determine the <br /> hydraulic transmissivity of the first water bearing zone This pump test will also function <br /> as a interim remedial action to remove free-product floating on the groundwater surface <br /> that has been identified to be present in all of the three existing monitoring wells <br /> • Mam\p\Environmenta"wmarTexaco\Workplan\042003 wpd 11 <br />