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2.0 ASSESSMENT HCSTORY <br /> 2.1 Initial UST Removal and Sampling Activities <br /> On April 21, 1993, two 10,000-gallon capacity, leaded gasoline underground storage tanks and <br /> one 5,000-gallon capacity, diesel underground storage tank (USTs) were removed from the <br /> subject site. Evax Technologies, Inc. inspected the tanks and collected soil samples from beneath <br /> the ends of each leaded gasoline UST, and one sample from beneath the fill end of the diesel <br /> UST immediately subsequent to removal. All samples were retrieved from the floor of the <br /> excavation at 13.5 feet bsg. Additionally, two soil samples were collected from the soil <br /> stockpile flanking the excavation. The stockpile was moved to the south end of the property <br /> prior to backfill of the excavation in May 1994. <br /> Analytical results of the soil samples revealed that elevated levels of Total Purgeable <br /> Hydrocarbons as gasoline (TPH-g) and total extractable petroleum hydrocarbons as diesel <br /> (TEPH-d), volatile aromatics benzene, toluene, ethylbenzene, xylenes (BTEX), and lead were <br /> present in the samples collected from the excavation and from the stockpile. <br /> The overexcavation of the former tank pit was initiated on July 16, 1993 by equipment operator <br /> Mark Burns and a W.W. Irwin, Inc. staff geologist as requested and contracted by the Pegasus <br /> Group. The work was periodically supervised by Mr. Michael Collins, SJCPHS-EHD <br /> Registered Environmental Health Specialist. As the excavation proceeded, soil samples were <br /> collected for lithologic analysis and organic vapor analysis (OVA) meter readings were taken <br /> in order to direct the excavation by determining the level of contamination and the direction of <br /> migration. The excavation was expanded slightly in all directions from the original tank pit to <br /> an area approximately 35 square feet and to a depth of approximately 18 to 20 feet below <br /> surface grade (bsg). The excavation was halted when the excavator reached the limits of its <br /> extension and the northern wall became inaccessible. Ground water was not encountered. <br /> W.W. Irwin, Inc. <br /> Project No. 33016.05&.06 <br /> August 1995 2 <br />