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0 • Former Countryside Market,Stockton,California Feasibility Study and Interim Remedial Action Plan May 20,2013 Soil samples from VW-1 will be collected at 5-foot intervals for poten ial chemical analysis, field screening, and lithologic logging purposes. Each sample will be collecte in an 18-inch long, 2-inch diameter, split-spoon sampler containing three clear 6-inch stainless steel sleeves for sample retention. Several intermittent depth samples may be collected from VW-1 to better identify lithologic contacts and/or to verify proper placement of the well screen. Soil samples will be visually classified in accordance with the Unified Soil Classification System (USCS) and screened for VOCs using a calibrated hand-held photo-ioniation detector (PID). Since the proposed well locations are within close proximity to the former U T area, soil samples from approximately every 20 foot interval, including at the capillary fringe/smear zone and at total depth, will be submitted for laboratory analysis unless the PID data indicates a modified sampling frequency is required. All soil samples collected for chemical analysis will be prepared in the field in accordance with EPA Method 5035 for transport under standard chain-of-custody protocol to a State-certified laboratory for analysis. The sampling equipment will be cleaned in an aqueous solution of Liqui-NoxTA4 cleanser or equivalent (non-phosphate), rinsed with tap water, and rinsed a second t me with de-ionized water to prevent cross-contamination between sample intervals. All samples to be analyzed and tested for TPHg and VOCs (including oxygenates) by EPA Method 82606 and for total lead by EPA Method 60106. Soil descriptions, PID readings, and other pertinent observation will be provided on the well construction logs. Select soil samples will also be collected for physical properties analysis to allow for groundwater velocity and oxygen uptake/biodegradation rate calculations, potential future plume modeling and/or alternative remedial technology assessments. Parameters to be measured in the saturated zone will include porosity, bulk density, and hydraulic conductivity. Similar vadose zone parameters may be measured if the soil data collected during sparge and observation well installation activities indicates active and/or passive remediation is potentially required above the groundwater table. Soil cuttings and auger decontamination water generated during drilling activities will be placed in labeled, United Nations-approved, 55-gallon steel drums and stored on!-Site pending receipt of the analytical results. All waste will be properly disposed in accordance with the applicable Federal, State, and local regulations. 5.1.3 Well Construction Details Sparge wells AS-1 and AS-2 will consist of two-inch-diameter, Schedul 80 polyvinyl chloride (PVC) blank and screen (0.010-inch slot) casing. The screen interval for the A• wells is expected to extend from approximately 105 to 110 ft-bgs, with the top of the screen interval a proximately 10 to 15 feet into groundwater. A five foot section of blank casing will likely be installed on each well from approximately 110 to 115 ft-bgs to serve as a sump (i.e., for potential silt/fines accum lation that tends to occur in Fe bdity SN y IF"Slbiliy S"&[R P_Te Final.da 5-3 The Source Group,Inc.