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s <br /> 1 1 <br /> October3992,. <br /> BP Oil Facility No. 11191, Stockton,California Working To Restore Nature <br /> SOIL _BORINGS / SAMPLING' AND ANALYSES / MONITORING WELL <br /> INSTALLATION <br /> our.soii'boring will be drilled using a truck-mounted drill rig'equipped with 8-inch=diameter <br /> hollow stem=augers. Soil borings will be,drilled adjacent to two corners of the existing fuel tank <br /> I' cavity and near the dispenser islands. The locations of the borings are shown on the Generalized. <br /> Site Plan (Plate 2). Soil-bio"rings will�bendriRed-to-ap&6Kiinately7 5"feet below grade or'- 0 <br /> approxiiiiateiy 10-feet below the first-encountered ground water if groundwater is encountered <br /> within 45 feet below grade. Soil'borings will`be=drilled 3`to,5 feet alto any confining Iayer <br /> encounteredlbeneatl%.the:uppermost water-bearing zone. U a confining layer is encountered;-the <br /> boring will be terminated and.backfilled with bentonite to the top of the confining layer before <br /> installing a ground water monitoring.well. The hollow stem augers will be' steam cleaned <br /> between each boring, and-all sampling equipment will be properly cleaned between sample <br /> intervals. We expect the drilling to be conducted over a one to two day period. <br /> Soil-samples will be collected at five-foot depth intervals,just above.first encountered..ground <br /> water(if present), and-at notable changes in sediment composition utilizing an 18-inch California- <br /> modified, split-spoon sampler equipped with 2-inch=diameter-brass sample sleeves. Samples <br /> will be,collected by advancing the auger to a point,just above the.sampling depth and driving the. <br /> sampler into'the soil. The sampler will be driven 18 inches with it standard 140 pound hammer s <br /> repeatedly dropped-30'inches. The number,of,blows required oto,drive .the sampler_ each <br /> successive.6-inch interval will be counted.and recorded to give an indication 4 soil consistency. <br /> Each soil sample will be screened for'volatile compounds.utilizing a.photoionization:detector <br /> '(PID). Drilling will be performed under the observation of a RESNA geologist, and the earth <br /> materials in the borings will be identified using manual and.=visual.methods; and classified as <br /> .drilling progresses according. to. the Unified,Soil' Classification .System. This work will.be <br /> performed under the supervision of a California registered_geologist. One sample from every <br /> sampling interval will be sealed with alumninum�foil, capped, taped, labeled, and placed on ice in <br /> t an insulated container. Soil generated through drilling will be stored on plastic sheeting pending <br /> -characterization for -disposal. .Soil will be disposed in an appropriate disposal facility by a <br /> by <br /> -BP selected bBP Oil'and contacted by RESNA. <br /> Soil samples selected for analyses from each of the four soil borings will.generaliy be the sample <br /> producing the highest reading on the PID and the'sample from.directly above first encountered' <br /> ground water.'.If ground water is not encountered, the soil sample producing the second,highest <br />' PID reading will also be analyzed in a laboratory.X The RESNA project manager may select other <br />+ appropriate'samples from the borings utilizing the.previously noted field screening techniques. <br /> Selected samples will be. analyzed by, -a State-certified .laboratory for total petroleum <br /> hydrocarbons as gasoline (TPHg) and diesel fuel (TPHd) using-U.S. Environmental Protection <br /> Agency (EPA) Method 8015 (modified).and for.benzene, toluene,ethylbenzene and total xylenes . <br /> (BTEX) using EPA Method 8020:: Analytical methods and detection limits will.conform to <br /> guidelines specified in the latest-edition of the Tri-Regional Recommendations of the California <br />#} Regional Water Quality.Control Board. <br />} 17050.01wP 2 <br /> e <br /> t <br /> f <br />