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Appendix D:Field Investigation Procedures and Boring Logs SOIL SAMPLING Soil cores were obtained using an approximately 5-foot-long, 3-inch-diameter core barrel sampler. The core barrel sampler contained a plastic acetate liner that retained a relatively undisturbed soil core from which samples were collected. The soil samples selected for analysis were cut from the plastic liners, sealed with plastic end caps and Teflon sheets, labeled with identifying information, and stored in a pre-chilled ice chest for transportation to the laboratory. A chain of custody form designating the samples to be analyzed and other information accompanied the samples to the laboratory. One soil sample was collected from each boring between ground surface and 5 feet bgs to obtain a sample for a human health screening evaluation(HHSE). If affected soil was observed in the boring, a soil sample was collected from the interval that appeared to be the most affected. If there appeared to be an interval of unaffected soil beneath the affected soil and above groundwater, a soil sample was also collected from the unaffected interval to obtain vertical delineation. If no affected soil was observed in the boring, in addition to the HHSE sample one soil sample was collected just above the groundwater table.2 GROUNDWATER SAMPLING Grab groundwater samples were collected by placing a clean, pre-packed well screen into the borehole and collecting samples using a check valve with poly tubing. The well screen was inserted into the outer rods of the Geoprobe Dual Tube sampling system, and a polyvinyl chloride(PVC)riser was screwed into the well screen and plumbed to the ground surface. The dual-tube rods were retracted, with the well screen and PVC riser remaining in the borehole. The tubing end of the pump was placed at the midpoint of the groundwater column to minimize the entrainment of sediment in the groundwater sample, the presence of which could artificially bias the analytical results. After purging the well casing, groundwater samples were decanted into EPA-approved laboratory-provided bottles, labeled, and placed in an ice-cooled chest pending analysis by Lancaster. SAMPLING LOCATIONS/SURVEY METHODS After completion, soil borings were geo-spatially located using a Global Positioning System (GPS)unit. The GPS survey methods were consistent with SAIC FTP No. 175, "Field Measurement of Physical and Topographical Features." EQUIPMENT DECONTAMINATION The decontamination of sampling equipment, which did not directly contact the samples, was performed in accordance with SAIC FTP No. 400, "Equipment Decontamination." Sample collection devices, which directly contacted the samples, were decontaminated in accordance with SAIC FTP No. 405, "Cleaning and Decontaminating Sample Containers and Sampling Equipment." 2. Geomatrix Consultants,Inc.,2005. Technical Approach to Site Evaluation and Decision-Making,Historical Pipeline Portfolio, Central Valley Region. February: D-2 a The Benham Companies,LLC "ra81 _,",,f,SW"N"'s