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City of Stockton TL 394-0074-01 May 4, 1994 Page 9 APPENDIX A STANDARD OPERATING PROCEDURE The standard operating procedures for drilling and soil sampling, installation of monitoring wells,monitoring well development,groundwater sampling,decontamination,hydrologic data collection and evaluation, sample handling and chain-of-custody, laboratory quality assurance/quality control, and disposal of rinsate and soil cuttings, are described in this appendix. The following procedures are supervised under the direction of a California registered geologist. A-1 Drilling and Soil Sam lin . Subsurface assessment permits will be filed with the San Joaquin County Environmental Health Department (SJCDEH) before conducting field operations. Underground Service Alert will be notified at least 48 hours prior to initiation of field activities. The soil borings will be drilled using a Central Mine Equipment Company 75 truck-mounted drill rig equipped with 7-5/8-inch outside diameter, continuous-flight, hollow-stem augers. Twining is a licensed drilling contractor under C-57 classification (Contractor's License No. 506159). The soil borings will be drilled under the direction of a Twining geologist. Soils encountered during drilling will be logged consistent with the Unified Soil Classification System. The soil boring logs will note soil types encountered at depth including consistency, soil moisture, particle size, color, and other distinguishing features. Soil samples will be retained using a 1-1/2-inch inside diameter split-spoon sampler. The sampler will be lined with three six-inch long stainless steel or brass sleeves for containment of the soil samples. Samples will be obtained by attaching the sampler to the drive rod, followed by driving the sampler into undisturbed soil below the lead auger with a 140-pound hammer that is continuously dropped 30 inches until the sampler penetrates 18-inches of soil. The number of drops will be recorded for each six-inch increment the sampler is driven into the soil and recorded on the field log of soil borings. The values for the bottom two six-inch increments will be added together to obtain a standard penetration resistance value for each sample. Once the soil sample is brought to the surface, the bottom sleeve will be capped with Teflon®tape, fitted with plastic caps, placed in a zip-lock plastic bag, and placed in a cooled ice chest for subsequent transport to Twinings laboratory. This sleeve will either be retained for laboratory analysis or stored temporarily. Soil retained in the two uppermost sleeves and the shoe of the sampler will be transferred into a plastic bag, agitated to enhance petroleum product volatilization, and field tested for organic vapors with a photoionization detector (PID). The operation of the PID is explained below.