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The second progress monitoring, scheduled for June 1, 1994, will be centered near VW-5 <br /> and VW-6. Drilling will continue in a concentric-like pattern until a high level of confidence <br /> for soil clean-up is achieved. However, drilling may be modified, expanded or decreased, <br /> depending upon the analytical results of individual soil borings. The locations of the third <br /> and fourth progress monitoring borings will be determined after the first two have been <br /> completed. <br /> If it is necessary to install additional vapor wells or vapor monitoring points, the soil borings <br /> will completed as 2-inch diameter vapor wells using 30 to 40 feet of slotted PVC screen. <br /> 3.2 Soil Sample Analysis <br /> Select soil samples from the borings will be analyzed by a state-certified laboratory for TPH <br /> as gasoline (EPA 8015111) and volatile aromatics (BTE&X; EPA 8020). Selected samples will <br /> also undergo bacteria and agricultural analysis. Soil samples will be analyzed to correlate <br /> with earlier analysis from remediation and monitoring well installation. <br /> 3.3 Procedures <br /> To meet the project objectives, the following procedures will be performed: <br /> 1) Prepare a site health and safety plan in accordance with the Occupational Safety and <br /> Health Guidance Manual for Hazardous Waste Site Activities - Prepared by National <br /> Institute for Occupational Safety and Health, Occupational Safety and Health <br /> Administration, U.S. Coast Guard and U.S. Environmental Protection Agency, <br /> October 1985. <br /> 2) Notify the CVRWQCB and PHS/EHD 48 hours prior to commencement of any <br /> work. <br /> 3) Drill a minimum of two (2) soil borings for each progress monitoring event. The <br /> borings will be drilled using a hollow-stem auger drill rig to depths not to exceed 60 <br /> feet. <br /> 4) Collect and log soil samples at 5-foot intervals. Auger returns will be logged in <br /> accordance with the Unified Soil Classification System. Samples will be obtained <br /> using a split-spoon sampler loaded with three pre-cleaned brass tubes. <br /> 5) Backfill borings with be backfilled with #3 Monterey (or equivalent) sand from total <br /> depth to 10 feet and with concrete from a depth of 10 feet to surface grade. Some <br /> soil borings may be completed as vapor wells in accordance with the procedures <br /> described in the FRP (July 31, 1993). <br /> 6) Decontaminate sampling equipment in a tri-sodium phosphate solution (TSP) and <br />