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Results Report for Subsurface Investigation and Second Quarter 1999 Groundwater Monitoring Report Moore Petroleum,5491 F Street,Banta,Califomia Page 3 SUBSURFACE INVESTIGATION: SOIL AND GROUNDWATER SAMPLING On April 8 and 9, 1999, Apex personnel supervised the advancement of eight soil borings (GP-1 through GP-8) at the subject property (Figure 2). Soil borings were drilled with the use of a Geoprobe rig using direct push technology. Soil samples were collected at five-foot intervals from the eight borings for laboratory analyses. In addition, the soil samples were screened for preliminary indications of contamination using a flame ionization detector (FID) and the soil was identified using the Unified Soil Classification System (U.S.C.S). A San Joaquin County Environmental Health Division representative was present during soil and water sampling activities. Groundwater was encountered at approximately thirteen feet below ground surface and samples were collected with the use of a bailer. Two soil samples and one water sample from each boring were submitted, under chain- of-custody documentation, to California Laboratory Services, of Rancho Cordova, California. All soil and groundwater samples were collected according to Apex Standard Operating Procedures (SOPs) which are included in Appendix A. Appendix B contains soil boring logs and field screening results for each of the eight soil borings. Soil and water samples were analyzed for: total petroleum hydrocarbons, as gasoline (TPHg) and total petroleum hydrocarbons, as diesel (TPHd) by EPA Method 8015 Modified; benzene, " toluene, ethylbenzene, total xylenes (BTEX), and methyl tertiary butyl ether (MTBE) by EPA Method 8020. Analytical results for soil and water samples from this investigation are included in Tables I and 2, respectively. Analytical reports and chain-of-custody documentation are included in Appendix C. Direct push technology does not create any soil stockpiles. Soil borings were back filled with a cement grout mixture using a tremmie pipe, GROUNDWATER MONITORING Groundwater Levels On April 22, 1999 Apex personnel collected groundwater-level measurements from four of the six monitoring wells in accordance to the Apex Standard Operating Procedures (SOP) included as Appendix A. Groundwater monitoring well MW-4 was destroyed during the UST removal process. MW-6 was not located due to recent gravel addition to the northern portion of the site. All groundwater elevations were measured to the nearest 0.01 foot, referenced to the surveyed top-of-casing elevations. Groundwater level measurements collected since January 1993 are summarized in Table 3. A groundwater contour map of the shallow water-bearing zone on April 22, 1999 is shown on Figure 3. SB:C:1Project Files\Moore Petroleumlgp_rr.doc