SITE INFORMATION AND CORRESPONDENCE

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DRILLING, SEALING, WELL CONSTRUCTION AND SAMPLING PROTOCOLS Exploratory Boring Drilling and Sealing Exploratory boring and well construction, and borehole sealing procedures follow guidelines recommended by the USEPA, California Regional Water Quality Control Board, and modified as required by City, local or water district agencies. Drilling is performed only under approved permits and boreholes are sealed upon completion. Soil/Sediment Sampling Procedures 1 . Drive (or hydraulically push) soil sampling will commence at a depth of 5 feet below surface grade. The samples will be taken at 5 foot increments and at intervals of geologic interest or obvious or suspected contamination. Additional sampling and/or continuous coring may be done at the discretion of the supervising geologist. All logging will be done using the Unified Soil Classification System, together with pertinent geologic observations(bedding, fractures, fossils, mineralogy etc, as appropriate for the site geology). Continuous core will be placed in core boxes for storage at the Client designated area. 2 . Soil sampling tools (split spoons, cores, etc.) will be disassembled, steam-cleaned or cleaned in soapy (TSP) water, rinsed with clean tap water and finally rinsed with or distilled water, and air-dried prior to taking each sample. The cleaned tools will then be reassembled with similarly cleaned, dry brass sample liners and carefully lowered into the hollow stem augers for the collection of the next sample. The drill rig will be decontaminated as needed and at the discretion of the logging geologist. 3 . When sampling stockpile soils or during excavations, the soil sample will be collected by the following procedure; a clean brass liner will be pushed into the stockpile or soil in the excavator bucket. About two inches of soil will be brushed away and the liner pushed into the soil. The liner is then removed, sealed, labeled and logged onto chain-of-custody forms and packed in a chilled ice chest. 4. The soil samples in the lowermost of brass liners in the sampling tool (if in good condition) will be retained for chemical testing. The samples will be labeled and sealed in the field in their original Iiners. Sample liners ends will be sealed with aluminum foil, capped with clean cap plugs, and taped. 5 . The remaining soil sample will be extruded from the other rings in the field and lithologically logged. Sampler shoe cuttings, drill rig response and bit penetration rate will also be logged. The cuttings and the soils samples not retained for chemical analysis will be placed in 55-gallon drums pending chemical analysis and off-site disposal. 6 . All samples retained for chemical analysis will be stored on ice in a clean, covered cooler-box for transport to the Laboratory. Wright Environmental Services, Inc. rev. 6/2/94 Geoscience Protocols Page 1