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SOIL ASSESSMENT FOR PROPERTY ACQUISITION Intersection of Interstate 205 and Grant Line Road Tracy, California Delta Project No. 40-89-052 Page 6 No odors were detected during examination of the soil samples by a Delta geologist. Two soil samples from soil boring SB-2 were analyzed for TPH and BTEX. This boring was drilled in an area with visible motor oil surface staining in order to evaluate the condition of soils directly beneath the stained surface. The sample collected at 2.5 feet below ground surface showed a trace amount of toluene and undetectable TPH concentrations (Table 1). The sample collected at a 5- foot depth in this boring showed undetectable concentrations of TPH and BTEX. One soil sample collected in soil boring SB-6 at a depth of 6 feet below ground surface was submitted to the laboratory as additional confirmation that the site soils are free of petroleum constituents. TABLE 1 Chemical Analysis of Petroleum Hydrocarbons in Soil Concentrations in parts per million (ppm) Total Depth Below Petroleum Sample Ground Surface Hydrocarbons ID (feet) (TPH) Benzene Toluene Ethylbenzene Xylenes 562-1 2.5 <0.2 <0.002 0.003 <0.002 <0.002 S82-2 5 <0.2 <0.002 <0.005 <0.002 <0.002 SB6-2 6 <0.1 <0.001 <0.001 <0.001 <0.001 The sample composited by the laboratory from surface samples collected in soil borings SB-1, SB-3, SB-4, SB-5, and SB-6 was analyzed for the pesticides and herbicides listed in Table 2. The only chemical detected in this composite sample was dichlorodiphenyl-trichloroethane (DDT) at a total threshold limit concentration(TTLC) of 0.02 milligrams per kilogram (mg/kg). Chapter 30, Article 11 of the California Administrative Code (CAC) Title 22 provides the criteria for identification of hazardous wastes for the State of California. Section 66699, paragraph (c) of Article 11 lists organic and persistent bioaccumulative toxic substances and their soluble threshold limit concentrations (STLC) and total threshold limit concentrations (TTLC). Any waste is a hazardous waste which contains a substance listed in paragraph (c) at a concentration which exceeds its listed STLC or TTLC. The STLC for DDT is 0.1 milligrams per liter (mg/1). The TTLC for DDT is 1.0 mg/kg. The concentration of DDT detected in the composite sample is well below the stated action level. 4.0 SUMMARY Based on the classification of soil samples collected at 5-foot intervals from soil borings SB-1 through SB-6, the site appears to be underlain by 4 feet of clayey sands overlying at least 6 feet of clayey silts. The first occurrence of ground water in the borings was noted between 5.5 to 9.5 feet below ground surface.