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I <br /> s d <br /> I <br /> ' operating within established laboratory control limits The laboratory flagged select TPH <br /> detections because either the fuel pattern did not resemble the standard (Y-flag) and/or heavier <br /> ' (H-flag) or lighter(L-flag) hydrocarbons contributed to the quantitation The laboratory flagged <br /> select MTBE and BTEX detections with a C-flag, indicating that the specific compound had <br /> ' been detected,but the relative percent difference (RPD)between columns exceeded 40 percent <br /> ' In addition, select data had corresponding surrogate recoveries that were below acceptable limits <br /> (*-flag), therefore the results may be negatively biased and relatively low compared to actual <br /> ' concentrations Overall, the results of the field and laboratory QA/QC are of sufficient quality to <br /> support the findings presented in this report <br /> ' 5.0 FIELD OBSERVATIONS AND LABORATORY ANALYTICAL RESULTS <br /> ' This section describes the subsurface conditions for the 541 Site and surrounding area based on <br /> the results of the field investigation and laboratory testing programs The analytical results are <br /> summarized in Tables 3 and 4 and the laboratory reports are provided in Appendix C <br /> ' 5.1 Soil and Groundwater Conditions <br /> ' The subsurface conditions are depicted on the idealized subsurface profiles shown on Figures 5 <br /> and 6 The cross section location map is shown on Figure 4 The 541 Site and vicinity are <br /> ' underlain by artificial fill and clayey deposits with mterbeds of sand, silt, and gravel to the <br /> maximum depths explored (19 feet) The paved areas along the sidewalks and parking lots have <br /> ' approximately 3 to 6 inches of reinforced asphaltic concrete pavement The artificial fill is <br /> characterized by disturbed and more granular material that is typically 2 to 5 5 feet thick The <br /> ' fill consists of dark brown sandy and clayey gravel and gravelly and sandy clay The northern <br /> half of the 541 Site and the Tracy Express Wash & Lube property have the greatest fill thickness <br /> Brown to gray clay and sandy clay underlies the artificial fill These stiff to medium stiff clays <br /> are interbedded with varying amounts of silty and clayey sand and silt (Figures 5 and 6) The <br /> sandier layers are predominant to the south near West Grant Line Road and generally thin out <br /> i 1 <br /> F'zeld Investigation Report 12 8 December 2003 <br /> ' TREADWELL&ROLLO,INC <br />