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Over-Excavation Soil Sampling Results Report and Closure Request <br /> Arch Road Cardlock,4733 South Highway 99 Frontage Road,Stockton,California <br /> Page 2 <br /> certified analytical laboratory. The samples were analyzed for: total petroleum hydrocarbons <br /> (TPH) as gasoline by EPA Method 5030; TPH as diesel by EPA Method 3550; benzene, toluene, <br /> ethyl benzene and total xylenes by EPA Method 8021B; and MTBE, TBA, DIPE, ETBE, TAME <br /> and ethanol by EPA Method 8260B. Three of the dispenser locations exhibited elevated <br /> concentrations of fuel hydrocarbons. <br /> In a report titled Dispenser Pan Upgrade Soil Sampling Results Report, Apex proposed to <br /> conduct additional soil excavation in all locations exhibiting elevated concentrations of <br /> petroleum hydrocarbons and/or additives above the laboratory detection limits. <br /> The San Joaquin County Environmental Health Department (SJCEHD) replied via telephone that <br /> it would only be necessary to conduct additional excavation in three locations (dispensers 5, 8 <br /> and 10). <br /> OVER-EXCAVATION AND CONFIRMATION SOIL SAMPLING <br /> On June 9, 2003, Apex personnel supervised the over-excavation of the three dispenser locations <br /> and collected confirmation soil samples from all sidewalls and the base of the excavation (Figure <br /> 2). A representative of the SJCEHD was on hand to supervise soil sampling activities. The <br /> excavation at dispenser location 5 extended to a total depth of 5-feet below grade surface (bgs). <br /> The excavation at dispenser locations 8 and 10 extended to a total depth of 11-feet bgs. <br /> Upon review of the preliminary laboratory data, it was determined that additional excavation and <br /> soil sampling would be necessary to the north and east of the original excavation. Therefore, on <br /> June 26, 2003, Apex personnel supervised the excavation of additional soils and collected three <br /> additional confirmation soil samples. <br /> All soil samples collected at the site during this phase of the project were transported under <br /> chain-of-custody(COC) documentation to a state-certified analytical laboratory for analysis of: <br /> TPH as diesel (TPHd); and benzene, toluene, ethyl benzene and total xylenes (BTEX). The <br /> confirmation sample collected from dispenser location 5 was only analyzed for methyl t-butyl <br /> ether. Results of the confirmation soil samples are summarized in Table 1. <br /> Very tight inorganic silts with clays were encountered during the excavation. All soil samples <br /> collected from the bottom of each excavation contained tight inorganic clayey silt soils. <br /> All fieldwork was conducted in accordance with the Apex Standard Operating Procedures <br /> included in Appendix A. Soil disposal receipts and transportation manifests are included in <br /> Appendix B. All laboratory analytical results and COC's are included as Appendix C. <br />