ARCHIVED REPORTS_MONITORING WELL INSTALLATION AND BIOSPARGE EVALUATION REPORT

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1 ' wells. 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 washed thoroughly with a Liquinox (or equivalent) solution and/or a heated pressure washer. A PSC geologist supervised the drilling, sampling, and well construction activities. The decon water generated during the field activities was stored in DOT- approved 55-gallon drums. ' 2.2.1 Soil Boring Logging and Sampling Soil sampling commenced on 5-foot intervals for lithologic identification and laboratory ' analysis. The samples were collected in clean brass and/or stainless steel liners contained within California-modified split-spoon samplers (or equivalent). The samplers were advanced a minimum of 18 inches for each 5-foot interval. For samples selected for laboratory analysis, ' the liner was capped with Teflon tape and then with the appropriate end caps. The sample sleeves were labeled using a permanent marker and writing directly on the sample sleeve. The label included "sample ID (depth range)", date, and time. The sample was then double ' bagged and placed in an iced cooler. The sample information was then added to the chain-of- custody to accompany the samples to the laboratory. ' Soil samples were examined for lithologic identification in accordance with the Unified Soil Classification System and the Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), American Society for Testing and Materials (ASTM) ' Designation D2488 (ASTM 2000). The sample descriptions, observations, and any indications of contamination were recorded in the field on geologic logs and on field activity logs. A portable field photo-ionization detector(PID) was used to monitor for organic vapors and to measure headspace vapors from the soil samples. Logs of soil boring are presented in Appendix B. 2.2.2 Groundwater Monitoring Well Construction The groundwater monitoring wells were constructed using 2-inch diameter Schedule-40 PVC casing. The screened portion of the wells contained 0.010-inch milled-slots and were 10 foot in length. The "B" Zone well (CT-MW-8-87) was set with the screen bottom at approximately 87 feet bgs. The "C" Zone well (CT-MW-9-120) was set with screen bottom at approximately 120 feet bgs. An appropriately sized filter pack (Lonestar 02/12 sand) was ' placed in the annular space of the borehole adjacent to the screened interval. The filter pack was extended 2 foot above the screened interval to allow for settlement during well development. A 2-foot thick seal, consisting of hydrated bentonite '(3/8-inch chips), was ' placed above the filter pack in the annular space of the borehole. Grout slurry, consisting of neat cement, was placed above the bentonite seal in the annular space of the borehole to within 6 inches of the surface. ' Upon termination of the soil borings and prior to completion of the well installations, the SJCEHD grout inspector was notified for grouting approval. Borehole grouting was ' completed with a neat-cement grout mixture consisting of approximately 2.5-gallons water to each 47-pound bag of Type II-IV Portland cement. Grout was placed in the well annulus using a tremie pipe. Upon approval of the grout inspector, the grout was delivered by gravity ' Monitoring Well Installation and BioSparge Evaluation Report ' Prepared For:Sara Lee Bakery Group,Inc. 9 Prepared By:PSC lmi.wial Oumomcing,LP Sam Lee—Lincoln Street 2009_12_03-MW Installation&BioSpmge Evaluation Report(Rnal).doc Report Date:December 3,2009