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Phase li Environmental Site Assessment Multi-Modal Station Stockton,San Joaquin County,California Page 24 made to ensure the absence of airspace in the far to prevent volatilization of the sample (BK4-730- OWSI) The sample was labeled, chilled with ice, and transported by courier under chain-of custody procedures to Excelchem for analysis The sample was analyzed for VOCs by EPA Method 8260B, and TPH-G and TPH-D by EPA Method 8015m The laboratory analytical results are summarized in Table 12 Laboratory data sheets and the chain-of-custody form are included in Appendix F Table 12—Analytical Results of Material Inside Concrete Vault 730 E. Channel Street � C N V N C C N C q Constituent--; p :e e :2 .E� a°, o E P7 E c? o c 14 C 07 ro o a a cx Analytical Method--' 8260B 82608 8260E 8260B 826013 8260B 8260E 8260B 8015m 8015m 8015m 8015m 8015m Reporting Limit--+ 2 5 25 25 25 25 25 25 25 20 2020 200 10 1mg/kg mg/kg m g m m m m m g m m T&g m m Sample ID Date BK4-730-OWS1 1 9112102 1 6 8 1 11 1 19 1 94 1 89 12 12 76 2 0 1 13 1 46 3,400- 940 mg/kg=milligrams per kilogram=parts per million=ppm *=sample chromatogram does not match the standard chromatogram for this constituent and the result is an estimated value A trap door was observed on the floor of each of the two vehicle maintenance bays at 730 E Channel Street The trap doors were opened to explore their contents and to investigate the possibility of any piping leading to or from the bays The openings were measured to be 15 inches by 15 inches, and 20 inches deep The opening in the southern bay contained a black liquid that smelled like old motor oil The opening in the northern bay contained a black liquid with a sheen on the surface and red discoloration The liquid in this hole appeared to be a mix of water and oil, with a slight diesel odor A stick was used to investigate the walls and bases of the openings to identify drainage or piping No piping or drainage features were identified No samples were collected from these openings and the trap doors were replaced 6.0 SUMMARY/DISCUSSION OF RESULTS 6 1 CONE PENETRATION TEST BORINGS The geologic logs from borings CPTI through CPT5 were compared in order to evaluate the lateral continuity of the subsurface lithology beneath the site Representative geologic cross-sections depicting the subsurface lithology of the site were prepared by integrating the information contained in each of the CPT logs and selected Geoprobe and detection boring logs Geologic cross-section locations are shown in Figure 5, Appendix A Geologic cross-section A-A' (Figure 12, Appendix A) was constructed along an east/west orientation, looking to the north, and geologic cross-section B-B' (Figure 13, Appendix A) was constructed along a northwest/southeast orientation, looking to the northeast The CPT borings indicate the subsurface geology beneath the site is generally homogeneous below the six-block area Eolian sands, represented in the area on published geologic maps, were not noted in any of the borings completed during this investigation Soils encountered in the CPT bonngs were predominantly interbedded clays and silts with sporadically occurring thin beds of stiff fine-grained material and sand From the surface to a depth of approximately 27 5 feet bgs (CPTI) to 36 5 feet bgs (CPT4), the subsurface lithology is generally composed of interbedded layers of clay and silt with transitional layers of clayey silt and silty clay With the exception ,S �� CONDOR