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41Y �l Ms Lori Duncan May 20, 1999 Page 3 of 6 advance the borings and collect soil samples Soil samples were collected at 5-foot intervals using a 1-inch diameter by 24-inch long core sampler The sampler was lined with clear acetate sleeves, affording soil identification and subjective evaluation for contamination A flame ionization detector(FID) was used to monitor the presence of volatile organic compounds in the soil Four soil samples each from borings SBI and SB3, and three soil samples from boring SB2 were sealed, labeled, and immediately placed in an iced cooler for transport to a state-certified analytical laboratory Soil samples were selected based on observations and field screening results "Grab" groundwater samples were also collected from borings SBI and SB3 The samples were collected by driving the core sampler to the desired depth and exposing the screen to the bed within the formation A 0 17 diameter PTFE tube equipped with a stainless steel check valve was then inserted into the rods to the bottom of the of the sampler Water was extracted from the boring by creating a positive displacement effect within the tubing, forcing the water sample towards the surface where it was collected directly into sample containers Each completed boring was backfilled to the ground surface with neat cement grout No soil cuttings were generated All down-hole drilling and sampling equipment was decontaminated by washing with a laboratory grade detergent and rinsing with water Rinseate collected from decontamination procedures was disposed into the sanitary sewer by Fisch with consent from Mr Wong Soil and groundwater samples were submitted under chain of custody procedures to McCampbell for analysis • 4.0 RESULTS OF INVESTIGATION 4.1 Subsurface Conditions Soils encountered at the site consisted primarily of elastic silt to approximately 6 to 9 feet bgs, clayey sand to clay from approximately 6/9 feet to 11/14 feet bgs, poorly graded sand with clay, silt and clay from approximately 11/14 feet to 26/29 feet bgs, well graded sand from approximately 26/29 feet to 30 5 feet bgs, and silty sand to clay from approximately 30 5 feet to 36 feet bgs, the maximum depth explored Groundwater was initially encountered at a depth of approximately 23 feet bgs, and generally recovered to a depth of approximately 12 to 16 feet bgs Boring logs are included in Attachment 1 Strong petroleum odors were noted in boring SB3, located in the center of the former UST excavation, beginning at approximately 5 feet bgs Strong odors persisted to a depth of approximately 34 feet bgs, where only slight odors were noted Slight to moderate product odors were noted in boring SB 1, located approximately 15 feet northwest of the former UST, from a depth of approximately 15 feet to 25 feet bgs No petroleum odors were noted in boring SB2, which was located approximately 20 feet southwest of the former UST FID readings of samples collected from boring SB3 ranged from non-detect at 35 feet bgs to 2,000 parts per million(ppm) at depths of 15, 20, and 25 feet bgs FID readings from boring SB 1 ranged from 0 ppm at depths of 5 and 10 feet bgs to 960 ppm ata depth of 20 feet bgs The FID reading at the bottom of boring SBI (30 feet bgs) was 2 ppm FID readings for boring SB2 were non-detect for all samples except the one collected at 15 feet bgs, which was at 2 ppm groundzelgabbardlsumrpt doc