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�N-e %00 shoulder area of the State Highway 99 right-of-way. To evaluate subsurface conditions under the roadway surface, one of these three soil borings will be advanced at an angle of approximately 35 degrees off-vertical. The fourth proposed soil boring will be located on-site approximately 40 feet east of MW-1 so that the boundary of the plume of impacted groundwater may be delineated to the east of the former UST. To further define the vertical extent of impacted soil, the fifth soil boring will be positioned on-site, in close proximity to the former UST. The locations of the five proposed soil borings are shown on Figure 3. From all five of the proposed soil borings, undisturbed soil samples will be collected at five foot intervals to a total depth of approximately 20 feet bgs. The one soil boring positioned in close Proximity to the former UST will be extended to a total depth of approximately 25 feet bgs or until the vertical extent of impacted soil is defined. Soil samples will be collected by driving the Geoprobe sampler to the desired depth, retracting the piston tip into a sample tube lined with a one- inch diameter acetate sleeve and driving an additional two feet to displace the soil sample into the sleeve. The soil sample will then be extracted from the borehole to the surface using the Geoprobe rig. Afield geologist will log all soil samples for hydrogeologic and lithologic characteristics according to the Unified Soil Classification System and screen each sample for any hydrocarbon vapors using an organic vapor monitor equipped with a photoionization detector. A groundwater-grab sample will be collected from each of the five soil borings by lowering polyethylene tubing with a check valve down the hollow center of the drilling rod and into the groundwater column. Groundwater will be pumped to the surface using an oscillating motion. Following the groundwater-grab sampling, each of the soil borings will be abandoned using a neat cement grout. The borehole will be filled with grout from the bottom using a tremie tube. Soil and groundwater grab samples will be properly contained, labeled, preserved and transported under chain-of-custody documentation to a state of California certified hazardous waste testing laboratory for analysis. Up to three soil samples per boring and all groundwater grab samples will be analyzed on standard turnaround for TPH-as-diesel and TPH-as-gasoline by Modified EPA Method 8015 and for BTEX and MTBE by Modified EPA Method 8020. 2.3 Source Removal by Excavation Heavily impacted soil in the vicinity of the former UST will be excavated to remove the source of continuing impact to groundwater. 6