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soil was backfilled into the excavation. The results of the tank.removal are presented in Del <br /> Monte's Tank Excavation Report(Exceltech, 1985). <br /> In 1991, at the direction of the PHS/EHD, Del Monte began an investigation of the soil and <br /> groundwater in the vicinity of the Disco site. Del Monte retained CH2M HELL to conduct the <br /> investigation. The investigation consisted of a soil-gas survey to assess the extent of volatile- <br /> fuel constituents in the shallow soil, seven soil borings to assess fuel constituents in the soil, <br /> and the installation of eight monitoring wells to evaluate fuel"constituents in the shallow and <br /> deep groundwater. The results of the investigation revealed the presence -of gasoline <br /> constituents in the soil and groundwater. Most of the soil contamination was found below the <br /> former tank pit near the groundwater table, between 55 and 75 feet below ground surface. <br /> (bgs). Significant concentrations of gasoline constituents, including benzene up to 32 mg/L, <br /> were encountered in the groundwater. The results of this investigation and a feasibility study <br /> are presented in Del Monte's Remedial InvestigationlFeasibility Study(RI/FS) (CH2M HILL, <br /> 1992). <br /> i <br /> Since the 1991 investigation, Del Monte has conducted quarterly groundwater monitoring. <br /> The groundwater-monitoring results have been reported quarterly to the PHS/EHD. At the <br /> direction of PHS/EHD., Del Monte has also initiated remediation at the Disco site according <br /> to the RDFS. The remediation system consists of air sparging and soil vapor extraction <br /> (AS/SVE). The initial results of the AS/SVE system are described in this report. <br /> In two letters dated October 26,1994, and November 17, 1994,PHS/EHD directed Del Monte <br /> { to further define.the extent of contamination, install an,up-gtadient monitoring well and a <br /> Town-gradient monitoring well pair (one shallow and one deep), conduct aquifer pump tests, <br /> and prepare a Corrective Action Plan that addresses both soil and groundwater <br /> contamination. In response to PHS/EHD's directive, Del Monte submitted a December 29, <br /> 1994, work plan for completing exploratory groundwater sampling, well installation, pump <br /> testing, and preparation of an FRP. <br /> SFOl0030480.DOC 1-3 <br />