Laserfiche WebLink
2.4 Initial Investigation <br /> On 12 August 1994, two borings were drilled by GeoAudit at the site in the area of the <br />' former fuel dispenser island. TPH-g was detected at concentrations up to 13,000 ppm. <br /> TPH-g was detected at concentrations of 4 and 3 ppm at depths of 30 and 35 feet, <br />' respectively.No petroleum hydrocarbons were detected at a depth of 45 feet. Concentrations <br /> of total lead detected were consistent with normal background levels and below regulatory <br /> limits. <br /> 3.0 PROCEDURES <br />' 3.1 Drilling and Sampling <br />' On 22 February 1995, two additional borings were drilled using a DH-55 drill rig. The drill <br /> rig and two-man crew vvere supplied by Soils Exploration Services, Inc. (SES) of Benicia. <br /> Borings B3 and B4 were installed north and south of the former fuel dispenser island ' <br /> respectively, and advanced to depths of 35 feet. Soil cuttings were placed in 55-gallon drums <br /> and stored on-site. <br />' For both borings, discrete soil samples were collected ahead of the drill bit at 5-foot <br /> intervals using a split-tube sampler loaded with three pre-cleaned 2-inch by 6-inch brass <br /> sleeves. To avoid cross contamination, the sampling equipment was washed in an alconox <br /> solution and rinsed twice with water prior to each sampling run- For each sample, both ends <br /> of the lead tube were covered with aluminum sheets, capped and sealed with tape. <br />' Due to technical difficulties, a sample from Boring B3 at depth of 30 feet could not be <br /> collected. Therefore, a sample -was collected from 32 feet in this boring. <br />' The samples were then stored on ice and transported under chain-of-custody to Pan- <br /> Agricultural Labs, Inc.in Madera, California. Selected samples were analyzed for TPH-g and <br /> BTE&X-in accordance with EPA methods 80151n and 5020. <br /> .3.2 Logging <br />' Soil was extruded frons the second brass tube and screened for the presence of organic <br /> vapors using a photo-ionization detector (PID: Thermo Environmental SSOA, 10.0 eV, <br />' calibrated to isobutylene), and the readings were recorded on the boring logs. The soil was <br /> then described in accordance with the Unified Soil Classification System (see Boring Logs, <br /> Appendix A). The borings.were backfilled to-grade with portland cenient. <br /> „h,.. �.aE.wro.....: 2 <br /> FOUR WRNERSH-93JAGE-NC-93.0100 - <br />