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f 27 February 1997 AGE-NC Project No. 96-0273 Page 2 of 5 respectively (or 0.13 ppm, 0.16 ppm, 0.68 ppm and 0.28 ppm,respectively). Water was present in the UST excavation at the tirne of the removals; however, the'water was not sampled. 2.3. GROUND.WATER DEPTH AND FLOW DIRECTION Based upon information obtained from the PHS-EHD and this investigation, ground water depth at the site is approximately 12 feet below surface grade (bsg). Regional ground water flow direction in the area is reportedly toward the northeast. 3.0. PROCEDURES 3.1. DRILLING AND SAMPLING Three soil probe borings were advanced at the site on 18 November 1996. The probe borings were advanced using AGE's van-mounted Geoprobe 5400 soil probing machine. Probe boring P1 (probing P1)was advanced.north of the former 350-gallon UST excavation. Probe boring P2 (probing P2) was placed in the.center;and probe boring P3 (probing P3) was advanced south of the 350-gallon UST excavation. Figure 2 depicts the locations of the probe,borings. L Each probe boring was advanced to a depth of 15 feet bsg. Discrete soil samples were collected in each probe boring at 5-foot intervals beginning ata depth of 5 feet bsg; samples were collected using a 1.375-inch diameter two-foot long, piston type sampler loaded with four pre-cleaned 6-inch brass sleeves. The sampling equipment was washed in an Alconox solution and rinsed with water prior to each sampling run to avoid cross-contamination. d Upon sample retrieval,both ends of the second brass sleeve were covered with Teflon sheets,capped and sealed with tape. Samples were then placed in a chilled container and transported under chain-of- custody to McCainpbell Analytical, Inc. (MAI) in Pacheco, California. r • 3.2. SOIL LOGGING" LW Soil was extruded from the remaining brass sleeves and screened for the presence of organic vapor using a photo-ionization detector (PID: Thermo. Environmental 580A, 10.0 eV, calibrated to isobutylene). The soil was described in accordance with the Unified Soil Classification System.