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GEOMATRIX 4.1 SOIL BORINGS Three soil borings (GMX-10, GMX-11, and GMX-12) were advanced on August 4 and 5, 2003 by Gregg Drilling and Testing Inc. (Gregg Drilling)under Geomatrix oversight. Borings were advanced to depths ranging from 48.5 to 50.0 feet bgs using a Marl M5T drill rig equipped with 6-inch diameter hollow-stem augers. Boring depths were based on field observations of petro- leum hydrocarbon-impacted soil and capacity of the rig (i.e., the maximum depth at which drilling refusal was encountered). Drilling and soil sampling equipment was steam cleaned prior to advancing each boring. Samples were collected at five-foot intervals from each boring using a standard penetration test (SPT) split spoon drive sampler(1 3/8-inch diameter by 18-inches in length). Soil cores were logged by a Geomatrix geologist according to the Unified Soil Classification System(USCS) as presented in the American Society of Testing and Materials (ASTM) Standard D2488-90. Recovered soil was screened for organic vapors using a photoionization detector(PID) and observed for petroleum odor and staining. Field screening results are summarized on the boring logs included in Appendix B. In accordance with the work plan, a minimum of two soil samples were collected for laboratory analysis from each boring (GMX-10, GMX-11, and GMX-12). Soil samples were collected at depths of approximately 8 to 27.5 feet bgs in each boring to evaluate the presence of petroleum constituents in shallow soil within the vadose zone. The 27.5 feet depth correlates to the vadose zone/groundwater interface and the depth at which petroleum impacted soil was identified during previous investigations. Additionally, a soil sample was collected from the terminus of each boring to confirm the vertical extent of affected soil, if present (i.e., the sample was collected from a depth where field observations/measurements do not indicate the presence of petroleum constituents). Terminus samples were collected from depths of 47.5, 46.5, and 48.5-feet bgs in borings GMX-10, GMX-11, and GMX-12, respectively. An additional sample was collected at a depth of 41.5 feet from GMX-12 due to field indications (i.e., PID readings above background) that petroleum hydrocarbons might be present at this depth. Soil samples were collected in 6-inch stainless steel sleeves, sealed with Teflon sheets,plastic end caps, and silicon tape. Soil samples were labeled, sealed in plastic bags, and placed imme- diately in an ice-cooled chest for subsequent delivery to the analytical laboratory, Friedman and Bruya, Inc. (F&B), of Seattle, Washington(a State-of-California certified laboratory), under Geomatrix chain-of-custody procedures. I:\Doc_Safe\6000s\6447.001\OffSite Rpt\US Can SoilGW Rpt 2003.doc 6