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Mr. John Randall <br /> April 20, 1990 <br /> Page 5 <br /> In summary, two phases of excavations were performed at two on- <br /> site locations to excavate to the limit of contamination and/or <br /> the limit of the equipment. Soil samples collected from the main <br /> tank pit and waste-oil tank pit contained measurable concentra- <br /> tions of petroleum hydrocarbons. Since the excavation has <br /> reached its practical limits, Groundwater Technology recommends <br /> halting the excavation, aerating the stockpiled soils and <br /> backfilling the existing pits with the aerated soils. During the <br /> backfilling of the excavation, the clean overburden material will <br /> be used first. Once this soil has been depleted, it will be <br /> overlain by the aerated material. Following the backfill <br /> operation, three soil borings will be drilled and converted to <br /> groundwater monitoring wells. These well locations are presented <br /> on Figure 1. <br /> Y� TABLE 2 <br /> STOCKPILED SOIL SAXPLE ANALYTICAL RESULTS (3/29/90) <br /> parts per million (ppm) <br /> SOIL ETSYL- TPH-AS- <br /> SAMPLE BENZENE TOLUENE BENZENE XYLENES GASOLINE <br /> A-1 <0.005 <0.005 <0.005 0.03 <10 <br /> A-2 <0.)05 <0.005 <0.005 <0.005 <10 <br /> B-1 <0.005 <0.005 0.01 2 66 <br /> B-2 <0.005 <0.005 0.04 2 74 <br /> B-3 0.56 7 2 9 44 <br /> B-4 0.03 1 0.70 8 54 <br /> B-5 <0.005 <0.005 0.01 0.55 76 <br /> B-6 <0.005 <0.005 0.02 0.76 88 <br /> B-7 <0.005 <0.005 0.02 0.65 21 <br /> B-8 <0.005 <0.005 <0.005 <0.005 <10 <br /> B-9 <0.005 <0.005 <0.005 «0.015 I <10 <br /> B-10 <0.005 <0.005 <0.005 <0.015 <10 <br /> ND = Compound not detected at Method Detection Limits (MDL) <br /> The MDL for TPH-as-gasoline is 10 ppm. The MDL for Benzene, <br /> Toluene-and -EthyThen zene--is--0.005-ppm.-_The-MDL__for-_Xylenes is <br /> 0.015 ppm. <br /> J GRot'%'[jW%TFR <br /> TEC1;1if1,riCY,ISC. <br />