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WGuIR', Southwest, Inc. 8.1 SOIL BORINGS, SAMPLING,AND WELL INSTALLATION Three well boreholes (MW-1, MW-2, and MW-3) were drilled to a total depth of approximately 25 feet bgs with a Mobile Drill B-57 drilling rig equipped with 10 to 11-inch outer diameter (O. D.) hollow-stem augers. Pre-cleaned augers were used during the initial well construction and were decontaminated in the field to prevent potential cross contamination of subsequent wells. Undisturbed soil samples were collected at approximate 5-foot intervals at 5, 10, 15, and 20 feet bgs. The soil samples were collected in accordance with EPA SW-846 procedures using an 18- inch long, 2-inch I. D. split-spoon sampler lined with 2-inch O. D. metal sample tubes. All sampling equipment was decontaminated between sampling episodes utilizing a triple rinse method consisting of a wash with trisodium phosphate (TSP), a rinse with potable water followed by a final rinse with distilled water. Immediately upon collection of the soil samples, each end of the selected sample was covered with Teflon film and capped with a polyethylene lid. Each sample container was appropriately labeled. The samples were then placed immediately on ice and chilled to 4°C for storage and subsequent delivery to the analyzing laboratory. The samples were analyzed for NH3-N by EPA Method 350.2 and pH by EPA Method 9045. Soil samples were handled in accordance with the appropriate chain-of-custody guidelines. Soil samples were described in the field using the Unified Soil Classification System (USCS). Other information, which was recorded in the field and transcribed onto the soil-boring logs, includes sample collection depth, odor, soil description, and borehole completion information. Groundwater was observed in the soil samples at approximately 13 feet bgs in wells MW-1 and MW-2 and at 15 feet bgs in well MW-3. The boring logs are included as Appendix A. The work was performed under the direct supervision of a California Registered Geologist from WGR. The wells were constructed with 15 feet of 4-inch O. D., Schedule 40 PVC, 0.020" slotted well screen set from 10 feet to 25 feet bgs, with the remaining pipe to surface consisting of 4-inch O. D., Schedule 40 PVC blank well casing. Number 3 Monterrey Sand was used as a filter pack to approximately 2 feet above the screened interval in each well. The wells were surged to allow for filter pack settlement prior to placement of the annular seals. Immediately above the filter packs, seals consisting of 2 feet of hydrated chipped bentonite were placed. Neat cement grout 725.PRI.00 Page 5 December 4,2003