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A pre-cleaned stainless steel soil sampler containing one, 2-inch diameter by 6-inch long sample collection tube (brass or stainless steel) will be driven six-inches to one foot into the undisturbed natural soil by the slide hammer at each sampling location. The sample tube will then be removed from the sampler and prepared as described above. After collecting the surface soil samples, the pre-cleaned stainless steel auger will be advanced to a depth of two feet bgs. Following advancement of the auger, the decontaminated slide hammer sampler will be used to collect a soil sample as described above from the 2-foot bgs depth. As part of the PEA, the collection of background soil samples is required. These soil samples are collected because many compounds are known to be naturally occurring compounds pervasive in soils throughout the Central Valley of California. Therefore,by establishing a background concentration, any onsite detection can be accounted for as either naturally occurring or as residue from previous site activities. Due to the nature of the surrounding Site areas (primarily residential development) and because this Site was a portion of a much larger property which was all farmed similarly, it is unlikely that true background sample locations can be found. Therefore, it is proposed that the analytical data collected during the PEA process for a TUSD Site within two miles of this Site, the Freiler Elementary School, be used as the background data for this Site. If use of these data is unacceptable to the oversight agency, Site specific background samples will be collected and analyzed at locations selected by the on-Site agency representative. Prior to and between each sample collection location, all sampling equipment will be decontaminated with a laboratory reagent soap/deionized water wash followed by a deionized water rinse. Following sample collection activities, each borehole will be sealed shut with seal cement. 2.2 SAMPLE PREPARATION AND ANALYSES It is CRA's intention to analyze all of the surface soil samples and only to analyze a maximum of four subsurface samples (randomly selected by the analytical laboratory). The remainder of the subsurface samples will be maintained by laboratory for future analyses should the surface soil samples indicate concentration residues of concern. The proposed sample analysis matrix is presented in Table 2. As some of the samples are to be selected randomly for analyses by the laboratory, the sample matrix may change, however, the number of samples analyzed and the analytical parameters for the entire program will not. 031090-10(3) -4- CONESTOGA-ROVERS&ASSOCIATES