FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

BP Chemical April 28, 1992 02320 2258 Page 2 SOIL BORINGS On March 31, 1992, two soil borings were drilled to determine subsurface conditions beneath the site (Figure 2). The borings were drilled using a truck-mounted drill rig equipped with 8-inch outside diameter (OD), hollow stem flight augers. The drilling was supervised by a field geologist working under the direction of a California registered geologist. A log of materials encountered (soil types and evidence of hydrocarbons) while drilling was completed by the field geologist using the Unified Soil Classification System (Attachment I). Each boring was drilled to a depth of 40 feet bgs. No groundwater was encountered. All soil generated during the drilling operation was placed on and then covered with plastic (visqueen) on site pending proper disposal. After soil samples were collected, each boring was sealed with neat cement grout tremmied in place. SOIL SAMPLING Soil samples were collected at five-foot intervals in each boring. The samples were collected using a 2.5-inch OD by 18-inch-long modified California split-spoon sampler lined with three 2-inch-diameter by 6-inch-long brass sample tubes. At each sample interval, the split-spoon sampler was driven 18- inches ahead of the lead auger. Field observations and headspace measurements with a PID were used to field screen the subsurface materials. The results of PID screening are shown on the boring logs in Appendix A. The soil samples were subsequently sealed, labeled, and placed on ice in an insulated container. All samples were shipped with the appropriate chain-of-custody manifest to a State of California certified analytical laboratory. SAMPLE ANALYSES Two soil samples from each soil boring were analyzed for benzene, toluene, ethylbenzene and xylenes (BTEX), and total petroleum hydrocarbons-as-gasoline (TPH-G) by Environmental Protection Agency (EPA) method 8020, organic lead by the LUFT method, and ethylene dibromide by EPA method 8010, SOIL CONDITIONS Soils underlying the site consist primarily of clays to approximately 30 feet bgs overlying 10 feet of silty sands. Readings taken in the field with a PID showed no indication of hydrocarbon affected soil in the borings. No gasoline-related hydrocarbons, organic lead, or ethylene dibromide were detected in any of the analyzed soil samples. Table 1 summarizes the analyses. The corresponding laboratory reports and chain-of-custody manifests are contained in Attachment ll. CONCLUSION Based on analytical reports and field observation using a PID, soil in the vicinity of the two borings drilled on March 31, 1992 has not been affected by gasoline related hydrocarbons, organic lead, or ethylene dibromide. GROUNDWATER TECHNOLOGY