ARCHIVED REPORTS XR0002759 - Laserfiche WebLink

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ARCO Products Company 3 ARCO#4932,16 East Harding Way,Stockton,CA December 10,1999 Over-excavation of the UST complex was completed and samples were collected on iJune 9, 1999 Six samples were collected from the bottom of the UST complex at approximately 19 feet bgs TPH-g and MtBE were reported in one sample each at a concentrations of 102 mg/kg (T-2S@19') and 0 579 mg/kg (T-3S@19'), respectively Benzene and fuel oxygenates were reported as nondetect in all samples Over-excavation activities were observed and approved by Ms Lon Duncan with San Joaquin County Environmental Health Department Field and laboratory procedures are presented as Attachment B Certified analytical reports and chain-of-custody documentation are presented as Attachment C Stockpiled Soil Removal Approximately 781 tons of soil generated during the removal of the underground facilities and the over-excavation activities described above was stockpiled onsite Composite samples were collected to characterize the soil prior to disposal Between June 18, 1999and July 22, 1999, Dillard Environmental Services hauled the soil to BFI Landfill in Livermore, CA for disposal Stockpile analytical data is presented in Table 2 Certified analytical reports and chain-of-custody documentation are presented as Attachment C Soil disposal certificates are included as Attachment D SUMMARY OF FINDINGS • After over-excavation in the areas of the product lines and dispensers, TPH-g, benzene, and MtBE were detected at the maximum concentrations of 5,430 mg/kg, 10 6 mg/kg, and 55 5 mg/kg, respectively • After over-excavation in the UST excavation, TPH-g, and MtBE were detected at the maximum concentrations of 102 mg/kg and 0 579 mg/kg, respectively Benzene was reported as nondetect in all UST excavation samples j i • Approximately 781 tons of soil removed during UST and product line i� upgrade activities was disposed of at BFI Landfill in Livermore, CA • Groundwater was not encountered in the product line or UST excavations CONCLUSION Based on the data collected during the above-described field work, gasoline hydrocarbons have impacted soil primarily in the areas of the dispensers The most significant concentrations of hydrocarbons were reported in the area of dispenser samples D2, D4, and D5 Hydrocarbon concentrations reported at a depth of approximately 15 feet bgs in the area of the former USTs decreased to very low to nondetect at a depth of approximately 19 feet bgs Hydrocarbon concentrations in soil 077 41774 003/PULL.DOC