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1 <br /> Soil Baring 1 showed up to 2600 ppm TPH-diesel And 25 ppm <br /> TPH-gas under the old pump station. This material had been <br />' excavated down to about 8- 10 feet during the tank removal and <br /> then replaced . Native material gust under this fill ( 10.5' ) ran <br /> 1300 ppm-D and 49 ppm TPH-G and at 24 feet (23-25.5' ) the soil <br />' ran below reporting limit . <br /> Soil Poring 2 was located off the south end of the pit . This <br /> hole showed only 210 ppm--D at 14 .5 feet ( i4-15.5' ) . No <br />' contamination above reporting limit was found in two samples <br /> below this (24 .5 and 34 .5 feet ) . <br /> Soil boring 3 was at the north end of the pit . It showed <br /> contamination of 1500 ppm-D and 5.9 ppm TPH--G at 9.5 feet . No <br /> values above reporting limit were detected at 24 .5 or 35.5 feet , <br /> Soil boring 4 was located in the pit bottom. Sample <br /> elevations were measured from the pre-excavation surface <br />' <br /> Projected across the pit . Contamination of 280 ppm-D Was detected <br /> at 23 feet (22.5--24 feet ) . No contamination above the reporting <br /> limit was detected at the 35.5 foot level . <br />' TECHNICAL SUMMARY <br /> Based on these key technical characteristics of the site a <br /> list of alternatives have been developed to treat the site for <br /> closure. <br /> 1 ; The level of contamination from the site dissipates <br /> rapidly from the tank pit area . <br />' 2. The high level of clays in the zones underlying the <br /> tank pit will prevent rapid migration of hydrocarbons <br /> through the sail . Dispersion rates are probably in the <br />' range of 1 inch per day provided a continuous supply <br /> of contaminant was available. <br />' 3. It appears that the bulk of heavy contamination has <br /> been removed and stockpiled at the site during the <br /> Initial attempted treatment : <br />' 4 . No significant levels of highly mobile constituent from <br /> gasoline ( STEX ) have been encountered : <br />' S. There are no potential sensitive reteptor5 within 600 <br /> feet of the site . <br />' 6. There is a consistent confining layer of clay between <br /> the contaminated upper soils and the first ground <br /> water . <br /> 7. There is no potential for the groundwater seasonal <br /> fluctuation to encroach upon the contaminated area . <br /> 1 <br /> 2 _ <br /> T & T EARTH SERVICES <br />