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Phase H Environmental Site Assessment Multi-Modal Station Stockton,San Joaquin County,California Page 7 • samples collected from the borings were analyzed for VOCs by EPA Method 8260B Additional analyses Including those for SVOCs by EPA Method 8270C and petroleum hydrocarbon constituents by EPA Method 8015m were held pending the results of the VOC analysis 4.2.5 Groundwater Survey Condor representatives surveyed the location and elevations of detection borings In order to create a generalized groundwater gradient for the site The survey data were collected with a Trimble 5700 centimeter-level RTK Global Positioning System (GPS) and referenced to the North American Vertical Datum of 1988 [NAVD 1988 (U S Feet) (Accuracy±0 02 feet)] Laser level survey elevations (feet) of right-of-way borings were referenced to GPS survey points DMI, DC6, and DR3 (accuracy ±0 2 feet) The following boreholes were surveyed ➢ Right-of-Way - Detection borings DAI through DA3, DC1, DC2, DC6, DMI through DM3, DG 1 through DG5, "perimeter"detection boring PA i ➢ Block 3—Detection borings DBK3-930-1, DBK3-930-3 ➢ Block 4—All borings advanced on Block 4 properties The surface elevations of borings on Inaccessible private properties were Interpreted based on proximal surveyed points 4.3 ADDITIONAL WORK Descriptions of additional work performed in response to previously unknown or unidentified features of potential environmental concern are discussed in Section 5 4 . 5.0 INVESTIGATION RESULTS 5.1 CONE PENETRATION TEST BORINGS CPT borings CPT1, CPT2, CPT3, and CPT4 were advanced to an approximate depth of 120 feet bgs each CPT5 was advanced to an approximate depth of 174 feet bgs Field observations made during the installation of the CPT borings consisted of the real-time CPT boring logs, as well as PPDTs to evaluate the presence of groundwater at various depths In CPT-2, soil discoloration and a slight petroleum hydrocarbon odor were noted within the first five feet of the boring that were hand-augered CPT borings are shown in Figures 5 -11, Appendix A Geologic cross-section Ines are shown in Figure 5, Appendix A Generalized geologic cross-section A-A' (Figure 12, Appendix A) was constructed along an east/west orientation, looking to the north, and generalized geologic cross-section B-B' (Figure 13, Appendix A) was constructed along an northwest/southeast orientation, looking to the northeast 5 2 DIRECT PUSH BORINGS 5.2.1 Rbght-of-Way Between May 14 and September 13, 2002, two Geoprobe borings, 23 detection borings, and eight perimeter bonngs were Installed in the right-of-way of the six streets that enclose and transect the six- block area, as well as the railroad right-of-way properties in adjacent to the eastern portion of the site (Figures 5 - 11, Appendix A) ➢ Three "perimeter" detection borings (PSI, PS2, and PS3) were installed along the west side of N Stanislaus Street between E Miner Avenue and E Weber Avenue Boring logs of PS 1, PS2, and • PS3 are Included in Appendix D m(� CONDOR