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ON <br /> 2.5 Topography, geology, surface water, depth to groundwater: <br /> -� The site is situated on level ground comprised of <br /> Quaternary-Recent alluvial sediments. The water table lies <br /> .�, at about 40 feet below grade and flows to southwest based on <br /> San Joaquin Flood Control and Conservation District data. <br /> " The only surface water bodies within one-half mile of the <br /> site are .irrigation canals. <br /> is <br /> 2.6 Certified Laboratory <br /> a. <br /> Testing done by: Sequoia Analytical Laboratories <br /> 680 Chesapeake Drive <br /> Y Redwood City, CA 94063 <br /> DOHS Certification No. 145 <br /> Authorization to release Data Form is located in Appendix <br /> IT. <br /> 3.0 PROPOSED WORKPLAN <br /> To remove the remaining gasoline contaminated soils from the <br /> East wall of the tank pit WaterWork proposes to re-excavate <br /> the east wall. <br /> The following scope of work is proposed: <br /> .W l : Re-excavate the east wall of the tank pit to a maximum <br /> depth of 25 feet. In the north, south and east <br /> directions the excavation will be continued until visual <br /> and olfactory methods indicate that the hydrocarbon <br /> concentrations have been substantially reduced. <br /> 2.'' Collect two floor and four wall confirmation samples <br /> with the excavator bucket. One wall sample will be <br /> collected from the north and south walls. Two samples <br /> will be collected from the east wall. The samples will <br /> be collected at a depth of five feet above the bottom of <br /> the excavation. The samples will be analyzed by Sequoia <br /> Analytical Laboratory, a State certified laboratory, for <br /> benzene, toluene, ethylbenzene, xylenes (BTEX) and total <br /> petroleum hydrocarbons as gasoline (TPH) by EPA Methods <br /> 8015 and 8020. Tetra ethyl lead and ethylene dibromide <br /> will not be analyzed for, as previous sampling did not <br /> detect these constituents. <br /> 3. All excavated soil will be stored on-site, above asphalt <br /> ---an -covered with visquine. One composite samples (3 to <br /> 1) will be collected for every 25 cubic yards of soil <br /> removed. The samples will be analyzed for BTEX and TPH <br /> 2 <br />