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VIN ICK_�-IEBNf8 <br />Mr. Charles Leubner <br />20 January 1997 <br />Page 3 <br />On 19 December 1996, the contractor excavated the soil containing diesel leaked from the pipeline <br />and stockpiled the soil on plastic sheeting near the Bus Shelter. The middle stockpile shown on <br />Figure 2 near the Bus Shelter represents this soil (S9, 510, 511, S12). The contractor used an <br />organic vapor analyzer with a flame ionization detector (FID) to identify the soil around the tanks <br />containing diesel product from the pipeline blowout. The contractor's screening method consisted <br />of placing samples of soil in a plastic Ziplock bag and monitoring the headspace of the bag for the <br />presence of organic vapors. No soil samples were collected of material screened by the contractor <br />for laboratory analyses by the District (as represented by Helmick & Lerner Inc.) because the <br />contractor agreed to arrange for the profiling and disposal of this material. <br />Soil excavated from the vicinity of the blowout that the contractor's screening indicated no impact <br />by diesel was segregated into another stockpile as it was removed. That soil is shown in Figure 2 as <br />the northern stockpile located near the Bus Shelter. The remainder of the soil removed from the <br />excavation was added to the stockpile adjacent to Tanks T5 and T6. <br />The southern stockpile shown near the Bus Shelter on Figure 2 was from an area of stained soil <br />which was overexcavated due to the presence of petroleum hydrocarbons detected in a soil sample <br />collected from the northern end of Tank T7. Approximately 15 cubic yards of stained soil was <br />excavated from this area on 24 December 1996. This material was segregated from the other soil <br />and is the southernmost stockpile shown near the Bus Shelter. <br />Excavation and Stockpile Sampling <br />Mr. Jerry Yoshioka was the San Joaquin County Environmental Health Division Inspector in <br />attendance during the removal of the diesel tanks on 23 December 1996. Samples from the <br />excavation floor and stockpiles were collected by Mr. Noel Lerner of Helmick & Lerner Inc. and <br />were analyzed onsite by ExcelChem Environmental Labs in their State -certified mobile laboratory. <br />Although water was present in the excavation due to the heavy rains which occurred during the <br />weekend preceding the removal of the tanks, it was possible to obtained suitable samples of the <br />native soil that were not saturated with water. The location of the samples and the depths from <br />which they were collected are shown on Figure 3. <br />At the direction of the County, soil samples were collected from the floor of the tank excavations <br />using a backhoe bucket. Soil samples collected for laboratory analysis were obtained from the <br />backhoe bucket by scraping off the top several inches of soil with a steel trowel. A core sampler <br />lined with a brass or stainless steel liner was driven into the soil using a slide -hammer to collect the <br />sample. The liner was then removed from the core sampler and the ends of the liner were covered <br />with sheets of aluminum foil and capped with snug -fitting plastic caps. The samples were labeled <br />with a unique sample number, date and time sampled, and delivered to the mobile laboratory. <br />