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Appendix C:Field and Sampling Methods C.2 SOIL SAMPLING Soil samples were collected into U.S. Environmental Protection Agency (EPA)-approved containers and submitted to a California-certified laboratory, Lancaster Laboratories, Inc. (Lancaster)under SAIC chain-of-custody protocol, and analyzed for the constituents of potential concern(COPCs). SAIC also collected soil samples from less than 10 feet bgs for use in a human health risk assessment. Soil samples collected for the risk assessment were analyzed for the COPCs. Refer to Appendix E for more information and analytical reports. C.3 GROUNDWATER SAMPLING Pre-packed well screens (manufactured by Geoprobe)were installed in the borehole after drilling to total depth. The well screens were installed in general conformance with ASTM Method D6725-04. The well screens were constructed using 3/4 inch-diameter, 0.010-inch machine-slotted polyvinyl chloride well casing packed with 20/40 mesh sand and encapsulated in a stainless steel screen. Groundwater was purged using disposable tubing fitted with a check-ball valve until the parameters including temperature,pH, electrical conductivity, and turbidity stabilized or the temporary well dewatered. After purging, groundwater samples were decanted into laboratory- provided bottles, labeled, and placed in an ice-cooled chest pending analysis by Lancaster. Refer to Appendix E for more information and analytical reports. CA SAMPLING LOCATIONS/SURVEY METHODS Soil borings were geo-spatially located using a global positioning system(GPS)unit with sub- meter accuracy. The GPS survey methods were consistent with SAIC FTP No. 175, "Field Measurement of Physical and Topographical Features." C.5 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." In general, all non-dedicated equipment that came into contact with potentially contaminated soil or groundwater was decontamintated. Decontamination occurred before and after each use of a piece of equipment. For example, the down-hole equipment was cleaned between borings using a Liquinox%water solution to prevent the possibility of cross contamination. The equipment was decontaminated in a predesignated area on plastic sheeting, and the clean equipment was stored in an uncontaminated area. Specific decontamination procedures for non-dedicated sampling equipment vary by sampler type, and they are more fully described in SAIC FTP No. 405. Disposable equipment intended for one-time use was not decontaminted, but was packaged for appropriate disposal. Reusable sampling equipment that did not come into contact with potentially contaminated soil samples,but did require decontamination, included field test meters; the water-level sounder; direct-push drilling rig cutting shoes, drive heads,piston asemblies, samplers, and other fittings; C-2 96— a WIff mmfj'%i%�s From sclewe to Solutions