SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

<Wr7) Carcl"40 1117 Lone Palm Avenue,Suite 201 Modesto,California 95351 ATC 209-579-2221 Shaping the Future Fax:209-579-2225 Remedial Action Summary and Case Closure Report Eggiman's Property 1112 East Harding Way Stockton,California 1.0 INTRODUCTION Cardno ATC has prepared this Case Closure Report on behalf of Robert Eggiman to address the requirements for environmental site closure of the property located at 1112 East Harding Land, Stockton, California, Figures 1 and 2. This report is being submitted to the San Joaquin County Environmental Health Department (SJCEHD) to satisfy the No Further Action Required (NFAR) criteria. The r information provided addresses closure requirements outlined in Appendix A to the Tri-Regional Board Staff Recommendations for Preliminary Investigation and Evaluation of Underground Tank Sites. 1.1 Site Background In April 1987, SEMCO removed and disposed of two 1,000-gallon underground storage tanks (USTs) used to store regular gasoline, associated piping,and a fuel dispenser from the locations shown on Figure 2. A soil sample was collected from beneath the end of each tank at approximately 17 feet below ground surface (bgs). Analytical testing indicated the collected samples contained detectable concentrations of petroleum hydrocarbon constituents. The excavation was subsequently backfilled to the ground surface. On July 24, 1997, six soil borings were advanced to depths ranging from approximately 16 to 31 feet bgs to investigate the extent of residual soil contamination at the site. Detectable concentrations of total petroleum hydrocarbons as gasoline (TPHg), total petroleum hydrocarbons as diesel (TPHd), and benzene,toluene,ethylbenzene, and total xylenes(BTEX)were present in soil samples collected from the site. The distribution of petroleum constituents beneath the site was evaluated and appeared to be limited laterally to the immediate vicinity of the former tank pit. The highest concentrations were reported between 10 and 20 feet bgs and generally attenuate rapidly with depth. Attempts were made to further advance the Geoprobeo unit in several of the borings; however, probe refusal was encountered at depths ranging from approximately 16 to 30 feet bgs due to the hardness of the formation. The results of the subsurface investigation were summarized in Smith Technology's Summary Report, Subsurface Investigation, dated December 22, 1997. In April 1999, ATC conducted a sensitive receptor survey for the subject property. ATC reviewed groundwater well construction logs and conducted a site walk in the vicinity of the site to identify groundwater wells located within a 2,000-foot radius of the site. This survey identified 14 wells located within approximately 2,000 feet of the site. The closest of these wells is located approximately 800 feet upgradient of the project site. The receptor survey findings are summarized in ATC's Well Survey for Andrew and Edith Trust,for the Property at 1112 East Harding Way, Stockton, California, dated April 9, 1999. S:Enviromental\22493\Reports\Eggiman Closure Report.doc ) r