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Former Countryside Market, Stockton,California May 20,2013 Feasibility Study and Interim Remedial Action Plan 6.2.1 Pre-Field Activities and Boring Advancement Details Pre-field activities associated with the advancement of CPT-1 will be performed in general accordance with the items listed in Section 5.1.1. The borehole location will be cleared of obstructions/utilities by hand-augering and post-holing to five feet bgs, and the CPT assessrpent will be overseen by an experienced SGI California Professional Geologist. Subsurface lithologic and pore pressure data will be continuously recor led in the CPT sounding at approximately 2-inch (5 cm) intervals using an integrated electronic piezo ne system. The piezocone takes measurements of cone bearing, sleeve friction, and penetration pore pressure, and converts them soil behavior types according to the classification system developed by Robertson (1986). Soil behavior types are generalized classifications of soil conditions that are based on g obal curves rather than site- specific conditions. While the classification system is applicable to most situations, local variations or conditions may require additional interpretation methods. 6.2.2 Depth-Discreet Groundwater Sampling Based on the CPT-derived soil behavior type (SBT), cone bearing, sleeve friction, and penetration pore pressure data, depth-discreet groundwater samples will be collected for lab ratory analysis as the boring is advanced. The purpose of the multiple depth-discrete groundwater sampling will be to vertically assess groundwater impacts from the Site. Groundwater samples from the CPT boring will be collected using an HPT which utilizes an expendable tip at the end of a direct-push rod that is advanced to the base of the targe d depth interval. The direct- push rod will be retracted between two to five feet (various intervals), an a PVC screen, attached to blank PVC casing, housed within the direct-push rod is exposed to the formation. This allows formation groundwater from the desired interval to enter the screened interval for sampling. After the sample is collected from each interval, the down-hole rods are retracted from the b rehole, decontaminated (per standard procedures), and re-equipped with an expendable tip and internal casing/screen for advancement to the next desired depth (within the same borehole). Groundwater samples will be properly labeled and placed on ice in a cooler under proper chain-of- custody protocol for subsequent submittal to a State-certified laboratory for analysis by EPA Method 8260B for TPHg, BTEX compounds and oxygenates (TAME, TBA, EDB, ,2-DCA or EDC, DIPE, ETBE and MTBE). 6.2.3 Borehole Completion Details Upon completion of each boring, the entirety of the boring will be sealed with Portland cement. The surface will be repaired with concrete or other material to match the existing surface. Any decontamination water generated during the assessment will be prope ly labeled and contained for temporary storage at the Site in U.N.-approved, 55-gallon drums for apprDpriate disposal by a licensed waste contractor. Feasibility Study and Feasibility Sm y&IRAP_TW Finatdw 6-2 The Source Group,Inc.