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C City of Stockton A68109.018 July 18, 1997 Page 4 observation for straining or free fluids, unusual odor, and head space analysis using a it photoionization detector (PID). The procedure for performing head space analysis is described in the attached SOPS. Selected six-inch sections of the soil samples were preserved for chemical analysis in the laboratory based on the requirement of the investigation. The plastic liner was cut at the appropriate interval, the open ends sealed with plastic caps, label attached, and the sample was placed in a cooler for transport to Twining's laboratory under chain-of-custody documentation. Soil probe location SP-1 was intended to investigate soil beneath the former UST location. Soil samples representing sub-surface soil conditions at S, 12, 16, and 20 feet BSG were selected for laboratory analysis from soil probe location SP-1. Soil probe location SP-2 was intended to investigate soil adjacent to the west side of the former UST location. Soil samples representing sub-surface soil conditions at 12, 16, and 20 feet BSG were selected for laboratory analysis from soil probe location SP-2. Soil probe location SP-3 was intended to investigate soil adjacent to the east side of the former UST location. Soil samples representing sub-surface soil conditions at 12, and 16 feet BSG were selected for laboratory analysis from soil probe location SP-3. Drawing 2 shows the approximate soil probe locations (SP-1 through SP-3). The work plan called for an angle robe to be extended in a southerly direction beneath the P g p Y fire station building from the vicinity of the former UST. Based on the results of the field screening of the soil samples recovered from soil probes SP-1, SP-2, and SP-3 and with the approval of the SJCPHS representative, it was determined in the field that this angle probe was not required. The soil probe equipment was decontaminated after completion of soil sample collection at each probe location. The soil sampler was decontaminated after collection of each soil sample. After completion of sampling, the soil probe holes were backfilled with a neat cement slurry. The slurry was placed into the open probe hole through a tremie pipe (casing) in a manner to preclude creating voids. 4.2.2 Groundwater Investigation: A groundwater sample was collected from soil probe SP- 1's hole prior to backfilling. A temporary, 1-inch diameter, polyvinyl-chloride (PVC) casing was inserted into probe hole. The bottom ten-foot section of the PVC casing was machine cut with 0.01-inch slots. The casing was allowed to stand in the probe hole for a period of time deemed adequate for the groundwater to fill the casing below the water table. A groundwater sample was then collected through a 3/8-inch Teflon® tube with a positive displacement pump. Groundwater samples were decanted into appropriate sample containers, sealed, labeled, and placed in a cooler for transport to Twining's laboratory under chain-of-custody documentation.