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w April 15, 2009 4 Reference No. 17386-009 4.0 BOREHOLE INSTALLATION/SAMPLE COLLECTION As described above, the boreholes will be advanced by direct push (i.e. Geoprobe) methodology to the water table or to the maximum depths previously listed. Soil samples will be collected and logged continuously in 4-foot intervals using pre-cleaned, 2-inch outside diameter macro-core samplers containing 1.5-inch plastic liners and field screened for total organic vapors using a PID. The soil samples selected for laboratory analyses as described above will be collected in sample jars. The sample containers will be labeled with sample identification, the sampler's initials, the date and time collected, and requested analytical parameters; and placed on ice for shipment to the analytical laboratory under standard chain-of-custody protocol. If groundwater is encountered during advancement of the soil borings, a grab groundwater sample will be collected using low-flow groundwater sampling methods. The groundwater will be carefully transferred into laboratory supplied containers, minimizing volatilization of potential volatiles, and shipped to the laboratory as described above. All soil cuttings and decontamination and purge water will be containerized in a Department of Transportation (DOT) approved 55-gallon drum, as required by SJCEHD, and staged on-Site for future characterization and proper off-Site disposal. Following borehole installation/sampling, the boreholes will be sealed shut to the surface with Portland cement (neat cement) or as directed by the on-Site SJCEHD inspector (tremied from the bottom up if groundwater is encountered). A final asphalt/concrete surface patch will complete the borehole abandonment. 5.0 QUALITY ASSURANCE/QUALITY CONTROL During the advancement of the boring and sample collection and field analyses, a Quality Assurance/Quality Control (QA/QC) program will be employed. The QA/QC procedures include but are not limited to the following: • cleaning of drilling equipment prior to use at each boring location; • decontamination of sampling equipment prior to each location; • proper calibration of field equipment; • standard chain-of-custody protocol for transport for laboratory analysis to protect sample integrity; and • documentation of field procedures. Prior to sampling, all sampling equipment will be washed in an Alconox Solution, rinsed with potable water, and subjected to a distilled water final rinse. Disposable sampling equipment to be utilized during this investigation (including nitrile gloves and plastic bags) will be disposed between sampling intervals to prevent cross-contamination of samples. Encore Environmental Consortium, LLC