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Envi Construction -Development Science st Englneeriny Construc[ion•Development•industrial•Municipal g n e i e e.■ .. 45 Polk Stfout,3rd Floor•San Francisco,California 94102•415.49B.053S-cdimnngnrsennp,rarn CDIM Standard Operating Procedure 2.1 Subsurface Soil Sampling 1. PURPOSE This Standard Operating Procedure (SOP) establishes guidelines and procedures for collecting soil samples from the subsurface. Soils are generally classified as subsurface when they are beneath 12 inches below ground surface (bgs). Several methods may be used to collect subsurface samples from boreholes; the more common drilling methods and sampling procedures are described below. Proper collection procedures are necessary to assure the quality and integrity of all subsurface soil samples. Additional specific procedures and requirements will be provided in the project work plans, as necessary. Sampling of subsurface soil is generally conducted to: • Evaluate whether releases of hazardous substances have occurred from underground sources or surface spills/leaks; • Determine the extent of a hazardous release; • Estimate the volume of soil containing hazardous substances for removal, disposal or treatment; or • Provide confirmation soil data following remediation. 2. DEFINITIONS 2.1 Borehole Any hole drilled into the subsurface for the purpose of identifying lithology, collecting soil or water samples, and/or installing monitoring wells. 2.2 Hand Auger An auger consists of steel rods, typically with a bit on the lower end, with a T-shaped handle at the top which allows it to be rotated. Typically, 4-inch diameter auger rods are used. The auger is advanced into the soil by pushing and turning the handle. 2.3 Split Spoon Sampler Split spoon samplers consist of a steel tube, split in half lengthwise, with the halves held together by threaded collars at either end of the tube. A driving shoe at the bottom end of the sampler cuts into the soil, allowing the sample to enter the tube, and at the other end is a coupling which allows it to connect to the drilling rod. A standard split-spoon sampler (used for performing standard penetration tests) is 2 inches in outside diameter and 1-3/8 inches in inside diameter. This standard spoon typically is available in two common lengths, providing either 20- inch or 26-inch internal longitudinal clearance for obtaining 18-inch or 24-inch long samples, respectively. Six-inch long sleeves (tubes) of brass, stainless steel, or plastic are commonly placed inside the sampler to collect and retain soil samples. Five-foot and ten-foot long continuous split-spoon samplers are also available. A California modified split-spoon sampler is