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I ' GEOMATRIX Mr Jay Jahangiri Port of Stockton ' February 5, 2002 Page 2 • "Tri-Regional Board Staff Recommendations for Preliminary Investigation and ' Evaluation of Underground Storage Tanks," August 10, 1990, California Regional Water Quality Control Board, North Coast, San Francisco Bay, and Central Valley Regions IFour soil borings were advanced to a depth of 40 feet below ground surface (bgs) using a Geoprobe 5400 direct-push sampling ng (Figure 2) Ms Margaret Lagono of the PHS-EHD ' was on site during the field investigation Soil samples were collected at 5-foot intervals starting at 10 feet bgs (the approximate depth of the water table) and ending at 40 feet bgs The soil samples were collected using a Geoprobe Large Bore Soil Sampler(Appendix B) The soil samples were logged by a registered geologist using the Unified Soil Classification System as described in American Society for Testing and Materials Standard D 2488-90, "Standard Practice for Description and Identification of Soils (Visual-Manual Procedure) " The field bonng logs are included in Appendix A, final logs will be included with the final report The soil samples were screened for organic vapors using a photoionization detector (PID), and the PTD readings were recorded on the field bonng log The soil samples with the highest PID reading and the sample from the bottom of each soil boring were submitted using chain-of- custody procedures to the Port of Stockton's contract laboratory, Precision Enviro-Tech Analytical Laboratory of Stockton, California, for analysis Precision Enviro-Tech is certified by the state of California to perform hazardous waste and drinking water analysis Soil ' samples were selected in consultation with PHS-EHD for analysis of the following PHCs • benzene, toluene, ethylbenzene, and total xylenes (collectively referred to as BTEX) using EPA Method 8020 • total petroleum hydrocarbons quantified as gasoline (TPH-g) using EPA Method 8015M/DHS Discrete-depth grab groundwater samples were collected from each boring at depths of 20 and 40 feet bgs at the locations shown on Figure 2 To collect the groundwater samples, a Geoprobe Screen Point 15 groundwater sampler was used (Appendix B) Bonng B3-7 did not yield sufficient water at the 20-foot depth, so a groundwater sample was collected at 26 feet bgs The groundwater samples were stored in an ice-cooled container and delivered to the laboratory using chain-of-custody procedures for analysis of PHCs as described above The laboratory analytical data sheets for the soil and groundwater samples are presented in Appendix C After sampling was completed, each bonng was backfilled with neat cement grout using a Etremae pipe A representative of PHS-EHD was present to observe the backfilling operation I\PROJEC-86437 000/6437 Stte3 LatVert Results doe