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Z. proposed locations for soil borings and the groundwater monitoring well. Soil samples will be collected at five foot intervals and at changes in lithology following penetration of the side of the former excavation. Soil samples will be submitted for laboratory analyses based on PID head-space readings, odor, and staining observed. Up to ten (10) soil and one (1) water samples will be submitted for analysis using each of the following methods, EPA Method 8020 for benzene, toluene, ethylbenzene, and total xylenes (BTEX), total lead by EPA Method 6010, and EPA Method 8015 (DOHS modified gasoline, diesel, and oil) for TPH. Based on results of previous soil sample analyses, samples will not be analyzed for PCBs, volatile organic compounds, polynuclear aromatic hydrocarbons, or additional metals. 2.2 DRILLING METHODS 2.2.1 Soil Borings Soil samples will be collected in 2.5 inch diameter by 6 inch long brass rings contained in an 18 inch-long California modified split spoon drive sampler advanced below the lead auger by repeated blows of a 140 pound drop hammer. Samples will be collected at 5 foot depth intervals or at any change in lithology for logging and field screening. Lithologic logs will be prepared using the Unified Soil Classification System and other appropriate descriptions. Field observations such as hydrocarbon staining and odor will also be noted on the logs. Appropriate decontamination procedures will be followed for all soil collection and handling activities to assure that samples are representative and to avoid sample contamination and formation cross contamination. Specifically, all drill augers and drive sampler components will be cleaned by high-pressure steam cleaner prior to contacting the formation. Sampling equipment will be decontaminated between samples by washing in a tri-sodium phosphate solution, a tap water rinse and a final distilled water rinse. 2.2.2 Monitoring Wells A groundwater monitoring well will be installed near the soil boring location which exhibits highest in-place hydrocarbon impacts. The groundwater monitoring well will be installed within the eight inch diameter bore hole advanced by a truck mounted drill rig. The soil boring will be advanced until it is 15 feet into the first groundwater bearing formation or until an aquitard or aquiclude is encountered. A threaded end cap will be installed at the down hole terminus of a 20 foot section of a 0.02-inch slot 2-inch diameter PVC screen. Blank PVC piping will complete the well to surface. A filter pack of#3 sand or other appropriate filter pack material will be emplaced around the screen in the annulus of the boring to one foot above the top of the screened interval. The well will be surged during emplacement of the filter pact material to set the filter pack and to prevent bridging of the filter pack material. A bentonite seal will be placed u 2403c.20\stockton.pin 3