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��Claytnif <br /> Ms.Devra Lewis Page 5 <br /> RWQCB Clayton Project 70-03759.00 <br /> July 31, 2004 <br /> Soil samples from a depth of 6 feet will be preserved for analysis. The soil samples will <br /> be cut from select plastic liners, sealed with Teflon tape and plastic end caps, labeled <br /> with identifying information, and stored in a pre-chilled ice-chest for transportation to the <br /> laboratory. Soil samples will be recorded onto a chain-of-custody(COC)document that <br /> will accompany the samples to the laboratory and will designate which samples are to be <br /> analyzed. <br /> 3.4.2 Deep Subsurface Investigation <br /> If evidence of petroleum hydrocarbons is discovered in the shallow subsurface soils <br /> during the Geoprobe investigation, deep soil borings will be completed to assess the soil <br /> and groundwater encountered at deeper depths. Clayton will contract with a California <br /> licensed(C-57)driller to operate a truck mounted hollow stem auger drill rig. The <br /> hollow stem auger rig will be equipped with 6-or 8-inch diameter hollow-stem augers. <br /> During drilling activities, soil samples will be collected at five-foot intervals from each <br /> borehole for soil logging and possible laboratory analysis. <br /> The soil samples will be collected using an 18-inch long California-modified split-spoon <br /> sampler lined with brass or stainless-steel sleeves. The split-spoon sampler will be <br /> advance ahead of the augers at 5-foot intervals using a 140-pound hammer with a 30-inch <br /> drop. Blow counts will be recorded for each 6-inch segment. Soil samples from the <br /> hollow stem auger drilling will be collected from the lowest sampling sleeve in the split <br /> spoon sampler. <br /> Soil samples will be preserved for analysis if field evidence of impact by petroleum <br /> hydrocarbons is noted. One or more soil samples will also be preserved for analysis <br /> below the depth at which impact is observed to terminate. The retrieved soil samples <br /> chosen for analysis will be sealed with Teflon tape and plastic end caps, labeled with <br /> identifying information, and stored in a pre-chilled ice-chest for transportation to the <br /> laboratory. Soil samples will be recorded onto a COC document that will accompany the <br /> samples to the laboratory and will designate which samples are to be analyzed. <br /> Additional soil samples may be selected based on field screening techniques. <br /> 3.4.3 Soil Logging and Sampling <br /> Each borehole(geoprobe and hollow stem auger) will be.logged for lithological content <br /> using the Unified Soil Classification System(USCS) as a guide, and for color,relative <br /> moisture content, and other observable distinguishing characteristics(for example: color <br /> changes, debris,rootlets, or odor). Several unsaturated-soil samples will be selected from <br /> each borehole and placed into a sealed plastic bag for field screening using an Organic <br /> Vapor Analyzer(OVA)to evaluate for the presence of volatile vapors that may be <br />