ARCHIVED REPORTS_VAPOR INTRUSION SURVEY - SOIL GAS SAMPLING REPORT

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i i ' marked the general borehole location areas on the property and indicated total distances for utility clearance in white paint in the street or on the sidewalk in front of the Site for Underground Service Alert (USA), as required by California. Upon SJCEHD permit ' approval, PSC coordinated with USA to perform the utility locate. 2.2 Installation Procedures The concrete floor in the building was pre-cored in preparation for the soil gas boring. The exterior locations did not require surface coring. Each borehole was utility cleared by SubDynamic prior to advancing the borehole and temporary sample point installation. TEG-Northern California (TEG), a C57-licensed contractor, used a direct-push rig (AMF Power Probe) and installed the temporary soil gas sampling points. All drilling equipment ' and sampling tools were decontaminated prior to beginning the field activities and again prior to starting each boring (or as necessary). All reusable equipment was thoroughly washed with a Liquinox (or equivalent) solution. ' The temporary soil gas sampling points were installed via the direct-push rig equipped with 1-inch diameter steel drive rods fitted with a PRT threaded adaptor and a disposable drive point. The rods were advanced to approximately 6 feet bgs. Upon reaching the desired depth, the rods were withdrawn approximately 6-inches to expose the sampling interval. Approximately 12 feet of 0.187-inch nominal internal diameter disposable Teflon tubing ' fitted with a threaded PRT adaptor was then inserted through the hollow drive rods and threaded into the PRT fitting of the lead rod. An "O"-ring on the PRT adaptor was used to form an air-tight seal with the drive rods. Hydrated bentonite was used to seal gaps between ' the annular space around the drive rods and the ground surface. A diagram of the PRT soil gas sampling system and the field documentation is presented in Appendix D. ' A manifold consisting of stainless steel and/or brass tubing, compression Swagelok fittings, valves, and vacuum gauges were connected to the tubing coming out of the drive rods. The valves were closed to form a vapor-tight seal. A 6-Liter stainless steel SUMMA sampling ' canister was connected to the manifold nearest the manifold valve and vacuum gauge for the manifold leak check test and to purge the sampling train. A 1-Liter stainless steel SUMMA sampling canister was connected to the manifold at the furthest compression fitting to collect the soil gas sample. A diagram of the soil gas sampling system is presented in Appendix D. Upon termination of the boring and completion of the soil gas sampling, the SJCEHD grout inspector was notified and observed the grouting process. Borehole grouting was completed ' with a neat-cement grout mixture consisting of approximately 2.5-gallons water to each 47- pound bag of Type IHV Portland cement. The borings were grouted by gravity feed to the surface. The surface was then completed with cement or concrete. ' Upon completion of the soil gas sampling,the locations of the sampling points were measured to permanent fixtures and the Site maps were updated. The temporary soil gas sampling ' points were presented on GEO_BORE logs and uploaded into the GeoTracker database system. A copy of the boring logs are presented in Appendix E. Vapor Intrusion Survey Soil Gas Sampling Report ' Prepared For:Sam Lee Bakery Group,Inc. Papered By:PSC Industrial Outsourcing,LP Sam Lee—Lincoln Street\2009_03_31-Soil Gas Sampling Reporcdoc March 31,2009 7