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� f <br /> Woodward-CIV%..s <br /> Ms. Diane Hinson <br /> San Joaquin County Environmental Health Division <br /> February 23, 1996 <br /> Page 4 <br /> direct the contractor to remove approximately 81 cubic yards of pea gravel backfill material that is <br /> present in the excavation. The pea gravel backfill material will be stockpiled nearby for later use in <br /> Task 3. The polyethylene liner will be removed from the excavation. Approximately 16 cubic yards of <br /> diesel contaminated soil will then be excavated from the north end of the former UST pit. It is <br /> assumed that the excavation will encompass an area of 11' X 7' and will advance approximately 4 feet <br /> vertically into native soil below the pea gravel backfill material. <br /> A photoionization detector (PID) or equivalent will be used for field screening. When PID readings <br /> indicate that all of the contaminated soil has been removed, soil samples will be taken from the bottom <br /> of the excavation pit. The samples will then be subjected to immunoassay screening utilizing Petro <br /> FLAG hydrocarbon test kits calibrated for TPH as diesel. If the Petro FLAG screening results indicate <br /> that soils are above the acceptable limit (100 mg/Kg) set forth in the State of California Tri-Regional <br /> Board Staff Recommendations and the Leaking Underground Fuel Tank Guidelines which apply to the <br /> KJAX site, additional soil will be removed and new samples will be screened with a PID and Petro <br /> FLAG test kits. Once the screening results indicate that the soils are below the acceptable limit, no <br /> additional soil will be removed. At this point,two confirmatory samples will be collected. <br /> Task 2-Collect and Analyze Soil Samples <br /> WCFS will collect two soil samples from the bottom of the excavation to confirm the absence of <br /> diesel-contaminated soil in the excavation. The soil samples will be collected from the backhoe bucket <br /> under the approval of SJCEHD personnel. The soil samples will be collected with clean brass liners. <br /> The liner will be pushed into a chosen sampling point approved by SJCEHD, and Teflon sheeting and <br /> end caps will be placed on the ends of the liners. Samples will then be labeled with the sample number, <br /> time, and date. Samples will be placed on blue ice in an ice chest until transported to a California <br /> certified analytical laboratory. Proper chain of custody procedures will be followed. The samples will <br /> be analyzed for TPH as diesel using modified EPA Method M8015 and for BTEX using EPA Method <br /> 8020. Three Quality Control samples (QC)will also be submitted for analyses. One soil duplicate and <br /> one aqueous rinsate blank will be analyzed for TPH as diesel by modified EPA Method M8015 and for <br /> BTEX by EPA Method 8020. In addition, one aqueous trip blank will be analyzed for BTEX using <br /> EPA Method 8020 only. All samples will be analyzed on a 24-hour turn around basis. <br /> Task 3-Backfill Excavation <br /> Upon verification that all contaminated soils above the allowable limits (100 mg/Kg) have been <br /> removed, WCFS will request that SJCEHD give approval for the excavation to be backfilled. The <br /> contractor will use the material removed from the excavation and #2 sub-base material (or comparable <br /> material) from off site as needed. Following the backfilling activities, the contractor will compact the <br /> backfill material to match the existing grade surface. <br /> Woodward-Clyde Federal Services <br /> 8054z:\continv.ust\kj ax.ca\reports\wkpin.j ax <br />