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L30600 S. Corral Hollow RAO <br /> Exploratory Excavation Report <br /> Lftr. 2 <br /> LExcavation of the site started on November 17, 1998. The area around former tank#T-3 <br /> had previously demonstrated the highest concentrations of petroleum contamination. Soil <br /> was removed to the proposed depth OUK Work Plan 6-16-98) of 25 feet and exposed <br /> more contamination than was expected. The apparent fuel contaminated soil extended <br /> across the entire length of the tank trench, east to west, and back under dispenser #D-3. <br /> Digging continued to a depth of about 35 feet before the obvious contamination <br /> diminished. A soil sample, ME @ 40', was obtained from a depth of about 40 feet. This <br /> sample was non-detectable for the petroleum compounds, previously of concern, and.set <br /> Lthe format for a much larger excavation than previously proposed. <br /> Excavation continued through Thursday November 2&before a clean lateral interface, in <br /> all directions, became apparent. The soil from tank areas T-2 to T-6, and the related <br /> dispenser islands, was removed to a depth ranging from 38 feet to 45 feet deep. All soil <br /> removed from November 17'N to 20'h was stockpiled in soil pile"BP". <br /> Laboratorysamples were obtained from the floor and side-walls lis of the excavation and <br /> included stockpile BP. Sample locations were based on previous laboratory findings, <br /> Lapparent limits of contamination disclosed during digging, and accessibility. The locations <br /> were discussed and agreed upon with the San Joaquin Department of Environmental <br /> Health representative present during sampling and portions of the excavation work. <br /> t Laboratory results demonstrate that diesel, the primary contaminant, has been reduced to <br /> non detectable limits in the areas excavated (Appendix A). Traces of gasoline and some <br /> gasoline constituents were present in the bottom hole samples around former tank T-3. <br /> However, the deepest sample, 45 fleet, disclosed only 0.09 mg/Kg of Toluene. This <br /> concentration is well below State MCL and drinking water standards. <br /> Soli SamON <br /> Obtained from Floor and Side-walls of Excavation(11-17&20-98) <br /> LSample# Diesel Gasoline Benzene E-Benzene Toluene Xylenes MTBE <br /> EXT 8' ND ND 461M 40OW am ND <br /> EX2WO' ND ND ND ND ND ND ND <br /> EM(030' ND ND ND ND ND ND ND <br /> 40' ND ND ND ND ND ND ND <br /> 0' ND ND ND ND ND ND ND <br /> 30' ND ND ND ND ND ND ND <br /> EX7 15' ND 411WND <br /> 40' ND oft ND ed& ND <br /> ' ND ND M� ND &W meow <br /> WXl 45' ND ND ND ND ND ND <br /> VII@201 ND ND alt ND ND ND <br /> WXl 0' ND ND ND ND ND ND ND <br /> WX1 10' ND ND ND ND ND ND ND <br /> T3 40' ND ND ND ND ND ND I ND <br /> Note: All Units m mWKg ND=Non Detectable <br /> L <br /> L <br />