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Morita Brothers 7 May 6, 1992 <br /> v � i <br /> �J <br /> ' A total of seven soil borings were drilled within this phase of soil characterization <br /> (Figure 2) A soil boring (TH-1) was advanced through the northern end of the <br /> ' former eastern 5,000 gallon gasoline tank excavation and slant drilled at 200 from <br /> vertical to the south with a bottom hole location beneath the center of the tank to <br /> assess the vertical extent of impacted soil beneath this probable source Four soil <br /> borings (TH-3 through TH-6) were positioned to assess the lateral extent of gasoline <br /> ' concentrations in the soil A soil boring (TH-2) was advanced adjacent to the former <br /> location of the product pipeline adjacent to the northern dispenser island due to the <br /> overhanging canopy, and slant drilled at 200 from vertical to the east with a bottom <br /> ' hole location beneath the product line and dispensers to assess the vertical extent of <br /> impacted soil beneath this probable source The seventh soil boring (TH-7) was <br />' positioned to assess the lateral extent of gasoline concentrations in the soil in this <br /> area Boring TH-3 was position between the former leaking tank and product line to <br /> provide lateral information on both possible sources <br /> A field engineer working under the direct supervision of a California Registered <br />' Geologist was on site to log the borings, monitor soils during drilling for <br /> contamination, and collect soil samples Boring logs are presented in Appendix A <br /> Soil samples were collected at 5-foot intervals in each of the borings using a split- <br /> spoon sampler (ASTM D 3550 with shoe similar to ASTM D 1586) equipped with three 6- <br /> inch by 2 5-inch diameter stainless steel sleeves for soil retention The soil samples <br />' were obtained by driving the sampler with a 140-pound hammer dropping 30 inches <br /> in accordance with ASTM D 1586. <br /> The lowermost sleeve at each sample interval was screened for total organic vapors <br /> with a photo-ionization detector (PID) Headspace vapor analysis was performed by <br /> first discarding a portion of the soil retained at one end of the sleeve to produce a <br /> headspace The sleeve was then capped and the probe of the PID was inserted <br /> through a hole in the cap and into the headspace for analysis The PID readings are <br /> recorded on the boring logs and in Table 1 (see section 35, Soil Vapor Monitoring) <br />' EB-8 101-2 9204-Po44 RPT <br /> N <br />