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APPENDIX C: <br /> FIELD AND SAMPLING METHODS <br /> DRILLING <br /> From November 9 through 18, 2009, SAIC advanced 15 soil borings (SB-30 through SB-44)to <br /> total depths ranging from 20 to 35 feet below ground surface (bgs). The borings were advanced <br /> using direct-push equipment equipped with 5-foot acetate liners to collect soil samples. <br /> The completion of soil borings generally conformed to SAIC Field Technical Procedure (FTP) <br /> No. 525, "Soil Sampling Using an Auger." In accordance with the approach prescribed in the <br /> Consistent Technical Approach(Geomatrix Consultants, Inc., 2005)1, and to the extent <br /> practicable, SAIC attempted to collect soil samples from the target depth. <br /> The samples were screened with photoionization detection equipment, using procedures <br /> consistent with SAIC FTP No. 750, "Field Measurement Procedures—Organic Vapor <br /> Detection,"to detect the presence of residual petroleum in soil. The soil was logged in general <br /> accordance to the Unified Soil Classification System as presented in American Society for <br /> Testing and Materials (ASTM) 2488-90 under the direction of a California Professional <br /> Geologist. Other information was entered into field logbooks to document where, when, how, <br /> and from whom any vital project information was obtained,using procedures described in SAIC <br /> FTP No. 1215, "Use of Field Logbooks." <br /> Each open borehole was backfilled following completion of the soil borings according to San <br /> Joaquin County Health Services Department requirements. <br /> SOIL SAMPLING <br /> Soil samples were collected into United States Environmental Protection Agency <br /> (EPA)-approved containers and submitted to a California-certified laboratory, Lancaster <br /> Laboratories, Inc. (Lancaster) under SAIC chain-of-custody protocol and analyzed for crude-oil <br /> constituents. <br /> SAIC also collected soil samples from less than 10 feet bgs for use in a risk assessment. Soil <br /> samples collected for the risk assessment were analyzed for crude-oil constituents. Refer to the <br /> Data Usability Summary and Laboratory Reports (Appendix E) for more information. <br /> GROUNDWATER SAMPLING <br /> Pre-packed well screens were installed in the borehole after drilling to total depth. The pre- <br /> packed well screens, manufactured by Geoprobe, were installed in general conformance with <br /> ASTM Method D6725-04. The pre-packed well screens were constructed of 3/4 inch-diameter, <br /> 0.010-inch, machine-slotted polyvinyl chloride well casing packed with 20/40 mesh sand and <br /> encapsulated with a stainless steel screen. The external diameter was 2.5 inches. SAIC collected <br /> grab groundwater samples into EPA-approved containers using a peristaltic pump and disposable <br /> tubing. Groundwater parameters such as temperature, pH, electrical conductivity, and turbidity <br /> were measured during purging. After purging the well casing, groundwater samples were <br /> 1. Geomatrix Consultants,Inc.,2005. Second Draft Revised Technical Approach to Site Evaluation and Decision Making, Old <br /> Valley Pipeline Sites. February. <br /> C-1c - a <br /> NAF a ii <br /> jr2l`® <br /> from&;ewe to solutians <br />