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�. SOIL AND GROUNDWATER INVESTIGATION WORK PLAN �. Raymond Investment Corporation 145 N. Grant Street Stockton, California 1.0 INTRODUCTION This work plan was prepared by Condor Earth Technologies, Inc. (Condor) to describe proposed soil and groundwater investigation activities at 145 N. Grant Street (site) in Stockton, California (Figures 1 and 2, Appendix A). The purpose of the work is to investigate the lateral and vertical extent of petroleum hydrocarbon contamination related to an underground storage tank (UST) formerly located at the site. The proposed work will include advancing ten direct push borings to collect soil and groundwater samples for laboratory analyses. Condor prepared this work plan at the request of Ms. Beverly Garcia of Raymond Investment Corporation (property owner). Lo All work conducted by Condor will be under the supervision of a California registered geologist. This work plan includes project background information, a description of the field, laboratory, and reporting procedures proposed to conduct the work, and a project schedule. 2.0 PROJECT BACKGROUND On April 29, 2003, Oil Equipment Services removed one UST and associated piping at the site. The UST was discovered as part of a Phase 11 Environmental Site Assessment performed in May, June, and September 2002, and completed for the City of Stockton Department of Housing and Redevelopment. The San Joaquin County Environmental Health Department (SJCEHD) required removal of the UST. Condor representatives were on site to make field observations and collect soil samples following removal of the UST and the associated piping. Ms. Dina Abate of the SJCEHD was on site to observe the UST and piping removal activities and the collection of soil samples. The UST was an approximately 1,000-gallon capacity single-wall steel tank twelve feet long and four feet in diameter. The excavation associated with the UST was approximately six feet by fifteen feet by six feet deep. Soil staining and petroleum odors were noted in the excavation and excavated soil. Groundwater was La not encountered in the excavation. Approximately 85 feet of piping associated with the UST, a dispenser, and a diesel filter were also removed. Following removal of the UST, piping, dispenser, and filter, soil samples were collected from locations directed by Ms. Abate. The tank excavation was backfilled with pea W gravel. Laboratory analytical results indicated that petroleum hydrocarbons were not detected at or above the laboratory reported detection limits in the soil samples collected from the north end of the UST excavation, from beneath the dispenser, and from two piping trenches. Total petroleum hydrocarbons quantified as gasoline (TPH-G), total extractable petroleum hydrocarbons quantified as motor oil(TEPH-MO), and total extractable petroleum hydrocarbons quantified as diesel (TEPH-D) were detected at concentrations of 75 milligrams per kilogram(mg/kg), 18,000kg, and 2,400 mg/kg, respectively, in the soil sample collected from beneath the south end of the UST excavation at a depth of eight feet below the ground surface (bgs). TPH-G and TEPH-D were also detected at concentrations of 2.0 and 200 mg/kg, respectively, in the soil sample collected from beneath the location of the diesel filter. The UST removal activities and the results of 4W 4M CONDOR L.