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' June 5, 1998 - - Page 3 • Hoist Sampling On March 2, 1998 three samples (Sump, E Hoist, and W Hoist) were collected and analyzed for TOG The sump sample was also analyzed for TPH-g, BTEX compounds, and halogenated VOCs Soil analytical data for horst samples are summarjzed in Table 1 Certified analytical reports and chain-of-custody documentation is presented in Attachment B • Spoils Sampling. Thirteen composite samples, USTSP A through USTSP M were ' collected from stockpiled soil removed from beneath the USTs,product dispensers x product lines One composite sample (WOSP) was collected from the stockpiled soil d a removed from the waste oil tank pits Samples USTSP A through USTSP M were analyzed for TPH-g, BTEX compounds, MtBE and total lead Sample WOSP was analyzed for TPH-g, TPH-d, BTEX compounds, MtBE, TOG, CAM 17 metals, PCBs, volatile organics, and semi-volatile organics Soil analytical data for spoils samples are summarized in Table 2 Certified analytical ' reports and chain-of-custody documentation is presented in Attachment B FINDINGS The highest initial concentrations of petroleum hydrocarbons were found at the west end of the former tank complex and below removed product lines (see Table I and. Figure 2) Volatile and semi-volatile organics were detected in soil beneath the waste oil tank at sample location T-4 Soil was over-excavated at these areas and stockpiled for separate ' characterization (see I able 2) Subsequent deeper sampling at most of the impacted Iocations revealed decreasing concentrations of contaminants reported in shallow soils, some to nondetectable levels Locations where increasing contaminant concentrations were repgrted in deeper samples were T-IA, T-3A, and PL-3A In addition, although significant decreases in contaminant concentrations were observed following over-excavation, vertical definition of said contaminants was not completely achieved at locations T-6, PL-2, and PL-3 Further, detectable concentrations of 2-Methylnaphthalene and Naphthalene (0 80 ppm and 0 34 ppm, respectively) were reported at the current extent of vertical exploration (12 feet bgs) at location T-4 No detectable concentrations of volatile organics or other semi-volatile organics found in shallow soils were reported at location T-4 in the deep sample To facilitate future vertical definition near these area three 6-inch diameter Polyvinyl chloride (PVC) conductor casings were set at the locations depicted iFigure 2Residual TPH-g/Benzene/MtBE concentrations are also noted in Figure 2 920-172 [A/I NKPULI DOC.