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Mr. John Pollock N.W01 <br /> June 29, 1993 <br /> Page 2 <br /> SUBSURFACE INVESTIGATION <br /> Additional investigation was required by SJL.HD to evaluate the potential threat of <br /> soluble lead leaching to the groundwater surface. The groundwater surface at the site is <br /> expected to be located at depths ranging between 120 ft and 150 ft beneath the ground <br /> surface. <br /> Our subsurface investigation included drilling, logging, and sampling one soil boring <br /> to a depth of 15-1/2 feet, laboratory analysis of one soil sample for soluble lead, and <br /> preparation of this letter report of findings. <br /> Soil Boring <br /> The boring was drilled on June 16, 1993, by Jcon Exploration, a licensed well-driller, <br /> using a SIMCO portable drilling rig equipped with 6-inch outer diameter hollow-stem <br /> augers. Drilling equipment, including augers and samplers, were steam-cleaned prior to <br /> use in the boring. Soil samples were collected at 5-ft intervals in the boring using a <br /> California-modified split-spoon sampler fitted with clean stainless steel sleeves. The <br /> sampler was cleaned in an Alconox solution and rinsed with deionized water between <br /> samples. A photoionizing organic vapor meter (OVM) was used during sampling to detect <br /> potential hydrocarbon concentrations in the soil samples. Petroleum odors were not <br /> detected in the soil. <br /> Soils were logged using the Unified Soil Classification System (Figure 3). Drill <br /> cuttings were placed on plastic sheeting located in the alley between the garage and the <br /> neighboring antique store, covered with plastic, and left onsite pending the results of <br /> laboratory analyses. The soil boring was abandoned by backfilling with a slurry of neat <br /> cement with less than 5% bentonite powder. <br /> Three soil samples were collected from the boring. Each sample was trimmed of <br /> excess soil and sealed with aluminum foil, plastic caps, and airtight tape. Each sample was <br /> then labelled and placed into iced storage. The sample collected at a depth of 15 ft was <br /> selected and analyzed for soluble lead using a waste extraction test (WET) by Sparger <br /> Technology Analytical Laboratories of Sacramento, California. <br /> ROGER <br /> KOTT <br /> ASSOCIATES <br />