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3.0 PROCEDURES 3. 1 Drilling ' On March 2 , 3 and 9, 1993 , nine soil borings were drilled at the site. Borings #1 through #4 were placed at the corners of tank pit #1 and advanced to a depth of 30 to 35 feet. Boring #5 was placed next to the dispenser island and was drilled to a depth of 30 feet. Boring #6 was placed at the center of tank pit #2 and drilled to a depth of 20 feet. On 8 March 1993 , tank pit 02 was backfilled with ' 5/8" x 3/8" pea gravel to allow boring #6 to be placed at the center of the tank pit. Borings #7 through #9 were placed near the appurtenant piping and drilled to depths of 10 feet. Boring logs ' are included in Appendix C. The borings were advanced using a truck-mounted drilling rig equipped with 8-inch outside diameter hollow-stem augers. The CME- 75 H.T. drill rig and three-man crew were supplied by West Hazmat Drilling. The auger returns and soil sample duplicates were monitored for the presence of organic vapors using a photo- ionization detector (PID: Thermo Environmental 580A, 10 . 0 eV, calibrated to isobutylene) . M3.2 Soil Sampling Discrete soil samples were collected ahead of the drill bit using ' a split-tube sampler loaded with three pre-cleaned 2 by 6-inch brass tubes. The samples were collected at five-foot intervals. To avoid cross contamination, the sampling equipment was washed in a tri-sodium phosphate (TSP) solution and rinsed twice with water ' prior to each sampling run. For each sample, both ends of the lead tube were then covered with aluminum sheets, capped and sealed with tape. The samples were labeled, logged on a chain of custody and stored on ice pending transmission to WEST Laboratories in Davis. A total of 27 soil samples were analyzed for total petroleum hydrocarbons (TPH as ' gasoline) and purgeable aromatics (BTE&X) in accordance with EPA methods 8015 modified and 8020, respectively. Three samples from Boring #5 and two samples from Boring #6 were also analyzed for TPH as diesel and motor oil. Two samples from Boring #6 were also analyzed using the waste extraction test (WET) for zinc, chromium and lead (using de-ionized water) . On April 5, 1993 , eight soil samples were collected from the stockpiled soil on-site (approximately one soil sample per 25 cubic yards) . The samples were collected using a metric soil sampler pre- loaded with two clean, 2-inch by 3-inch brass tubes. The ends of the lead tube were covered with aluminum sheets capped and sealed with tape. The samples were transported under chain of custody to WEST Laboratories. For characterization purposes, these samples were composited at a 4 to 1 ratio and analyzed for TPH, BTE&X, 2