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_ QA N -�11.TNG 3.0 RESULTS 3.1 Geology and Site Conditions In general, the soil encountered at the Site consisted of horizontally non-continuous units of clay, silty clay, sandy clay, clayey sand, silty sand, and sand up to the termination of the borings (up to 30 feet bg). Groundwater was encountered from approximately 20 to 21 feet bg. Bedrock was not encountered at the test boring locations. Soil boring logs with descriptions of the encountered materials are contained in Appendix B. 3.2 Field Screening Field screening of the soil samples collected from the test borings did not detect elevated concentrations of organic vapors when screened with a PID, and unusual staining was not observed. 3.3 Chemical Analyses Chemical analysis of the soil samples collected from the test borings SB-1 and SB-2 indicated that VOC concentrations were below the laboratory method detection limits (MDLs). Chemical analysis of the soil samples collected from the test borings SB-3 and SB-4 detected trace concentrations of tetrachloroethene (PCE). The detected PCE concentrations were significantly below the EPA Regional Screening Levels (RSLs). The detected soil concentrations are summarized in Table 3 along with their respective RSLs. The laboratory analytical report is presented in Appendix C. TABLE 3 SOIL CHEMICAL ANALYSIS RESULTS(RESULTS IN MG/KG) 'RSL- 'RSL- Sample SB-1(2.2S'-S') SB-2(10'-12') SB-3.(4'-S') SB-4(4'-5') RESIDENTIAL INDUSTRIAL VOCs PCE <0.0012 <0.0013 0.0048 1 0.0036 1 22 110 Notes: mg/kg=Milligrams-per-kilogram or parts-per-million. RSL=California EPA Regional Screening Level. <=Less than method detection limit Concentrations in bold and shaded exceed the stated RSL. Chemical analysis of the groundwater samples collected from the temporary monitoring wells at SB-1 and SB-2 indicated that VOC concentrations were below the laboratory method detection limits. RALEY'S STOCKTON NOVA PROJECT NO.B13-0472 PAGE 5 APRIL 9,2013