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Soil Sampling Field Standard Operating Procedure SWE-FSOP-405;Revision 1 Ahtna Southwest Environmental Operations 4.2 Retrieval Techniques 4.2.1 Manual Retrieval Manual retrieval methods are commonly used to collect surface and shallow subsurface soil samples using hand tools such as stainless steel trowels, shovels, picks, etc. Surface soils generally include the interval from the ground surface to 6 to 12 inches bgs. However, project-specific plans and data quality objectives for the investigation should be reviewed to confirm specific intervals.The shallow subsurface interval may be considered to extend from approximately 12 inches bgs to a site-specific depth at which sample collection using manual collection methods becomes impractical (commonly around 2 feet bgs). For manual sampling, follow these general steps: • Ensure that the sampling area is safe for entry. If the sample is to be collected from within an excavation, ensure that the excavation meets all criteria for safe entry. • Use hand tools to access the depth required for sampling. If using a shovel or hand auger, place the soil cuttings on plastic sheeting or as specified in the work plan. If possible, lay the cuttings in order of depth. • When collecting the sample, collect soil from a freshly exposed surface. • Collect samples for VOC and TPH-GRO analyses first. 4.2.2 Hand Auger Sampling Hand augers may be used to collect soil samples in the surface and shallow subsurface intervals as a discrete sampling activity or during initial borehole advancement when using a drill rig. • Typically, a 3-inch stainless steel auger with cutting heads is used. • The auger is advanced to the specified depth, and the contents are transferred to a homogenization container for processing. • When collecting samples for analysis, hand auger holes should be advanced one auger length at a time until the sample depth is achieved. • When the sample depth is reached, the auger used to advance the hole should be decontaminated or removed and a clean auger attached. In the field logbook, record the depth that the clean auger is advanced during sample collection. • Because the auger may scrape material from the sides of the auger hole or material may slough into the bottom of the hole when the auger is extracted, judgment must be used to determine how much material in the top and bottom of the auger is not a representative sample and should be discarded. • If collection of samples for VOC analysis is required, they should be obtained directly from the auger before contents are emptied, if possible. • The entire hand auger assembly must be decontaminated before use when moving to a new sampling location. 4.2.3 Backhoe Sampling Backhoes may be used to collect surface and shallow subsurface soil samples, most commonly from trenches and other excavations where manual sampling directly from an excavated surface is not feasible or safe. Page 9 of 15