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`... 1.011.1 Geological Technics Inc. Page 3 Additional Site Characterization Work Plan Project No.723.2 December 10,2007 2.0 PROPOSED INVESTIGATION In their October 12, 2007 letter correspondence the SJC/EHD directed that a work plan be submitted for additional site characterization. In their letter they noted concerns regarding the vertical extent of soil contamination and the lateral extent of the groundwater plume. GTI has prepared the following work plan that address the SJC/EHD's concerns by advancing one on site soil boring and installing eight new monitoring wells. 2.1 Vertical Soil Definition Borehole A single borehole, S13-5, will be advanced in the vicinity of the former dispenser island. See Figure 2 for S13-5 borehole location. 2.1.1 Borehole Drilling Prior to commencing work, encroachment permits and soil boring/monitoring well permits will be secured and the SJC/EHD will be notified 48 hours in advance. The subsurface will be cleared of underground utilities by notifying Underground Service Alert. The borings will be drilled using an 8-inch outside diameter continuous flight hollow stem auger by an appropriately licensed driller. Soil cuttings will be containerized in DOT approved 55-gallon steel drums and held on site pending disposal. The expected depth to groundwater in this area is 32 feet below grade based on October 2007 depth to water measurements. 2.1.2 Soil Sampling Procedure The S13-5 boring will be free drilled from surface to 90 feet below grade surface (bgs). At this point the borehole will be continuously sampled to the total depth of 100 feet bgs. A boring log for S13-5 will be developed by a GTI staff geologist under the supervision of a professional geologist. The log will be prepared using the U.S.C.S. and field observations to provide sediment descriptions. Up to three soil samples shall be obtained from the boring for laboratory analysis. Soil samples will be collected in 6.0-inch brass liners using a 2.0-inch modified California split spoon sampler. All soil samples will be sealed with Teflon sheets, capped, labeled and placed in a cooler at 4° Celsius for transport to the laboratory following Chain of Custody protocol. A field observation process will be used to gather additional information through noting sediment type, especially grain size and clay content; moisture content; visible evidence of contamination, i.e., color change due to reduction of iron or discoloration from hydrocarbons and other pollutants, and any readings above background levels on an organic vapor meter (OVM).