ARCHIVED REPORTS_XR0011664 - Laserfiche WebLink

Home Browse Search

-= City of Stockton A68108.OIB July 18, 1997 Page 4 a 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 laboratory analysis 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 F-- in a cooler for transport to Twining's laboratory under chain-of-custody documentation. Soil probe locations were based on the location of the former UST as indicated in the plot — plan attached to the City's RFB letter dated January 11, 1996. Soil probe location SP-1 was intended to investigate soil beneath the former UST location. Soil samples representing sub-surface soil conditions at 8, 12, 16, 20, 24, 28, 32, 36, 40, and 44 feet BSG were preserved for laboratory analysis from soil probe location SP-1. Soil probe location SP-2 was intended to investigate soil adjacent to the south side of the former UST location. Soil samples representing sub-surface soil conditions at 12, 16, 20, 24, 28, and 32 feet BSG were preserved for laboratory analysis from soil probe location SP-2. Soil probe location SP-3 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, 20, 24, 28, and 32 feet BSG were preserved for laboratory analysis from soil probe location SP-3. i • Soil probe location SP-4 was intended to investigate soil beneath the fire station building on the north side of the former UST location. Soil probe SP-4 was advanced in an northerly direction on an angle of approximately 60 degrees from horizontal. Soil samples representing sub-surface soil conditions at 10, 14, 17, 21, 24, 28, and 31 feet BSG were preserved for laboratory analysis from soil probe location SP-4. Drawing 2 shows the approximate soil probe locations (SP-1 through SP-4). Drawing 3 shows a cross section view of soil probe locations SP-1 and SP-4. 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 4, 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). 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 i-- was inserted into probe hole. The bottom ten-foot section of the PVC casing was machine cut with 0.01-inch slots. The slotted casing was placed between the depths of 38 and 48 feet BSG. The casing was allowed to stand in the probe hole overnight, a sufficient period for 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