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1 <br /> I Workplan for Additional Assessment and Feasibility Testing 2 <br /> 7-Eleven,Inc.Store No.21756,853 East Yosemite Avenue,Manteca,CA October 17,2001 <br /> I Lateral and Vertical Plume Delineation <br /> To better delineate the source area and lateral extent of the 7-Eleven plume, one downgradient <br /> groundwater monitoring well and one vertical delineation boring are proposed to be installed as shown on <br /> Figure 2 (access permitting). The well is proposed to be installed to 25 feet below grade,screened from 5- <br /> 25 feet below grade. <br /> I <br /> To determine the vertical extent of the plume in the source area,the vertical delineation boring will be <br /> installed to a depth of 40 feet below grade using Simulprobe (dual-"barrel)technology. After drilling,the <br /> boring will be backfilled to grade with bentonite/cement and capped to match existing surface. <br /> Health and Safety PlanlPermits <br /> The existing site-specific Health and Safety Plan will be used during subsequent drilling operations. The <br /> Health and Safety Plan has been prepared as required by the Occtapational Safety and Health <br /> Administration (OSHA) Standard "Hazardous Waste Operations and Emergency Response"guidelines (29 <br /> CFR 1910.120). The document will:be reviewed and signed by all IT Corporation personnel and <br /> subcontractors performing work at the site. <br /> i <br /> i <br /> s <br /> All applicable permits will be obtained prior to field operations. <br /> On-site underground utilities will be marked by an underground utility company, and Underground Service I <br /> Alert(USA)will be contacted and requested to notify the local utility companies to mark the location of <br /> underground utilities surrounding the site. For offsite drilling, a private utility locating service may also be <br /> used. <br /> I <br /> Drigtgn Soil Sampling <br /> I <br /> i <br /> Drilling will be conducted using a truck-mounted drill rig equipped with 8-inch-diameter hollow-stem augers. <br /> Soil samples will be collected at 5-foot intervals to a total depth of each boring beginning at 5 feet below <br /> grade using a split-spoon sampler lined with 2-inch-diameter by 6-inch-lorig brass sample tubes. The <br /> hollow-stem augers will be steam-cleaned before drilling, and sampling equipment will be cleaned between <br /> each sampling interval. Each soil sample will be screened for volatile content using a photoionization <br /> detector(PID). Soils encountered during drilling will be logged using the Unified Soil Classification System <br /> by an IT Corporation field geologist,working under the supervision'of a California registered geologist. One <br /> sample tube from each sampling interval will be sealed with Teflon'sheets, capped,taped, labeled, and <br /> placed on ice in an insulated container. <br /> i <br /> a <br /> 21756SAW.DOC <br /> i <br /> r <br />