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San Joaquin County EHD September 5, 2008 Page 3 of 10 Soil Vapor Extraction Well Installation and Soil Sampling Ground Zero will supervise the installation of two (2) vapor extraction wells at the Site. Each VEW will target a specific sand unit logged during the advancement of CPTI and MWL The CPT soil behavior type log and the borehole log for MW 1 are included in Attachment A. The CPT log shows a distinct sand unit between 15 and 24 feet bgs bound by silts and clay above and thick clay unit below. The CPT and MW 1 logs show alternating thick sand zones and thin clay zones between 34 and 60 feet bgs. MW 1 indicates flowing sands from 69 to 76 feet bgs. Over the last six years the depth to the water table has averaged 51.5 feet bgs with a low of 63.5 recorded in August 2004. Ground Zero proposes advancing the first boring (VEWI) to a depth of approximately 55 feet below the ground surface (bgs) and the second boring (VEW2) to a depth of approximately 25 feet bgs. VEW 1 will be advanced approximately 15 feet northwest of MW 1 and VEW2 will be advanced about 30 feet northwest of MW 1 as shown on Figure 3. V&W Drilling, Inc. of Lodi, California (C57-720904) (V&W) will advance the borings using a drilling rig equipped with ten-inch diameter hollow stem augers. Soil samples will be collected at 5- foot intervals for soil classification, subjective analysis for contamination with a photoionization detector (PID), and possible laboratory analysis. After sampling, the borings will be converted into soil vapor extraction wells(VEW 1 and VEW2). The wells will be completed using 4-inch diameter schedule 40 PVC blank casing from surface to the screened interval. VEWI will use 20 feet of 0.10-inch slotted screen set from 35 to 55 feet bgs and VEW2 will use 10 feet of 0.10-inch slotted screen set from 15 to 25 feet bgs. A filter pack consisting of pea gravel will be emplaced from total depth to two feet above the top of the respective screened intervals. In each well the remaining annulus will be completed with four feet of hydrated bentonite pellets overlain by neat cement grout to the ground surface. The well tops will be fitted with locking caps and covered with traffic rated well boxes. A SVE well diagram is included as Figure 4. Up to three soil samples from each vapor extraction well location will be submitted for laboratory analysis. Soil samples will be collected in brass tubes, sealed with Teflon® sheets and plastic caps, uniquely labeled, temporarily stored on ice in an ice chest cooled to approximately 4°C, and will be delivered under chain of custody protocol to Argon Laboratories (ELAP #2359). Soil samples will be analyzed for total petroleum hydrocarbons as gasoline (TPHg) using EPA method 8015M, benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA method 802113, and gasoline oxygenate additives, including 1,2-Dichloroethane (1,2-DCA) and dibromoethane (EDB) via EPA method 8260B. GAGROUNDMHARRYS AUTO\Reports\Workplans\wp sve pilot test.doc