ARCHIVED REPORTS XR0010134 - Laserfiche WebLink

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' Draft . 3.0 SUMMARY OF INVESTIGATION RESULTS 1 This section summarizes site investigation results and presents ERM's ' conclusions regarding the extent of concentrations detected at the site and the potential for remedial action The conclusions presented within this ' section are based on the results of all investigation activities conducted at the site to date 31 SOIL The following subsections present a discussion of the chemical compounds detected in soils at each UST site 311 UST-1 ' Samples collected at the limits of the USTA excavation (UST1-4, UST1-5, UST1-7, UST1-8, UST1-9, and HB-15) detected TPH-g at concentrations ranging from non-detect (UST1-9) to 5,400 mg/kg (HB-15) No detectable �. concentrations of benzene were encountered in these samples ' The sample at HB-15 that contained 5,400 mg/kg was collected at a depth of 7 feet bgs, however, a sample collected at this location at 5 feet bgs did not contain a detectable concentration of TPH-g In addition, UST1-9, which is adjacent to HB-15, did not reveal a detectable concentration of TPH-g at 6 feet bgs Therefore, because ground water was encountered at a depth of approximately 7 feet bgs, the detection of TPH-g at HB-15 is likely associated with TPH-g to ground water, not soil Samples collected beyond the limits of the excavation (HB-16 through HB-19) contained concentrations of TPH-g ranging from non-detect (HB-17 through HB-19) to 680 mg/kg (HB-16) No detectable ' concentrations of benzene were encountered in these samples HB-16 is adjacent to HB-17 where no TPH-g was detected in the vadose zone, therefore, the detection of TPH-g at HB-16 is considered isolated 312 UST-2 ' Previous samples collected at the limits of the UST-2 excavation (UST2-1, UST2-3, UST2-6, and UST2-7) contained TPH-g at concentrations ranging from 20 mg/kg (UST2-1) to 14,000 mg/kg (UST2-7) With the exception of ' 7