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GEOMATRIX <br /> 3.3.1 Soil Sampling <br /> Between October 20 and 28, 2003, Gregg Drilling and Testing, Inc., of Martinez,California, <br /> advanced 12 soil borings (ASB-1 through ASB-12) within the Arcos property with oversight by <br /> a Geomatrix field geologist. Borings were advanced to depths ranging from 40 to 55 feet bgs <br /> using a DP-11 MARL 2.5 drill rig on October 20 and 21, 2003, and a MARL M5T drill rig for <br /> the remaining dates. Both rigs were equipped with 8-inch diameter hollow-stem augers. <br /> Boring depths were based primarily on field observations of petroleum hydrocarbon-impacted. <br /> soil and subsurface drilling conditions. Drilling and soil sampling equipment was steam <br /> cleaned prior to being used at each boring location. <br /> Soil samples were collected from each boring using a modified California drive sampler <br /> (1.5-inch diameter by 18 inches or 2 feet in length). Soil cores were logged by a Geomatrix <br /> geologist in accordance with the Unified Soil Classification System as presented in the ASTM <br /> J Standard D2488-90. Recovered soil was screened in the field for organic vapors using a PID. <br /> Soil samples were also examined for indications of petroleum hydrocarbons, i.e.,petroleum <br /> odor and/or staining/discoloration(greenish gray color). Boring logs are included in <br /> ` Appendix B. <br /> Two shallow soil samples were collected for laboratory analysis from borings ASB-1 through <br /> ASB-3 at approximately 1 and 5 feet bgs. Shallow soil samples were collected from ASB-4 <br /> through ASB-12 at approximately 1, 5, and 10 feet bgs. Additional samples were collected <br /> } from the depth interval where the most affected soil was observed (e.g.,high PID readings, <br /> JI petroleum odor, and/or soil discoloration). Soil samples were also collected at first water and <br /> } at the terminus of the boring where affected soil was not observed, where applicable. <br /> Soil samples were collected in 6-inch stainless steel or brass sleeves sealed with Teflon sheets, <br /> plastic end caps, and silicon tape. Soil samples were labeled, sealed in plastic bags, and placed <br /> Jimmediately in an ice-cooled chest for subsequent delivery to F&B under Geomatrix COC <br /> procedures. <br /> 3.3.2 Grab Groundwater Sampling <br /> -) First groundwater was encountered at about 35 to 37 feet bgs in the soil borings. Grab <br /> groundwater samples were collected from borings ASB-1, ASB-5 through ASB-8, and ASB-10 <br /> -.� through ASB-12 to assess groundwater quality at locations where field evidence of petroleum <br /> hydrocarbons in soil (e.g., petroleum odor, PID readings, and/or soil discoloration) was not <br /> observed. The grab groundwater samples from these borings were collected at a depth between <br /> LTROJEcn5000A501 .000 5011-03.doc 15 <br /> _J <br />