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Report—Pit Closure Page 3 612 N.Buena Vista Ave. Project No. 480.2 September 26, 2007 2.0 SITE MITIGATION & DATA COLLECTION The attached site map shows (Figure 2) the subject Property and its improvements. Locations of the monitoring wells are shown on the map as is the former brine pit location and the recently installed Geo-Probe soil boring. 2.1 Preliminary Site Work A permit-to-drill was obtained from the San Joaquin County Department of ' Environmental Health. Underground Service Alert (USA) had previously been contacted to mark locations of buried utilities and determined that no such ' buried utilities are present in the vicinity of the soil borings. 2.2 Geo-Probe Soil Boring On March 9, 2007, Geo-Phase Environmental mobilized to the site to install a soil boring and collect a background groundwater sample using a Geo-Probe drilling rig owned and operated by V & W Drilling (C-57 License #720904). ' The Geo-Probe is a truck mounted drilling system that uses direct-push technology to collect soil and groundwater samples. Four-foot long by 3/4-inch ' diameter steel rods are pushed or hammered into the ground using a hydraulic ram or the hydraulically actuated hammer mounted on the ram. The lead 4-foot section consists of a 1.5-inch diameter soil sampling/coring device. The soil boring, designated as B9, was located at the foot of Buena Vista Street ' near the levee that contains the ship turning basin (see attached site map) Soil samples were collected continuously using a 4-foot long by 1.5-inch inside ' diameter drive sampler fitted with a full-length, plastic sample sleeve. Upon retrieval, each soil sample was examined for the purpose of geological logging. A log of the boring was kept that noted the soil characteristics such as lithology, color and texture at four-foot intervals. Other information logged included sample times, and soil staining and odors. Upon completion of the sample examination, the soil samples were discarded. Prior to completing the Geo-Probe boring, a groundwater sample was collected from near the base of the boring: The boring tools were driven or hammered to rthe desired depth and then withdrawn. A temporary well was then completed by inserting a length of 3/ inch flush-joint PVC casing, with the lead 5 feet being machine slotted with 0.010-inch slots. A groundwater sample from the Geo- Probe boring was then collected by oscillating a clean dedicated section of Teflon tubing fitted with a check valve, which was inserted inside of the slotted temporary casing. Sample material was collected in a 1-liter amber glass jar provided by the analytical laboratory. The sample container was then sealed, ' 2937 Veneman Ave.,#B240 Geo-Phase Environmental Inc. Phone (209) 569-0293 Modesto, CA 95356 Fax (209) 569-0295