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'. 2.2 GRAIN SIZE AND TOC TEST RESULTS Draft <br /> Two soil samples were collected from borings (HB-17 and HB-20) <br /> advanced at each former UST location for analysis of grain size and TOC <br />' 221 Grain Sue <br /> The results of the grain size analysis are presented in Table 5 and copies of <br /> the analytical results are presented in Appendix A As shown in Table 5, <br /> the samples collected at HB-17 (11 feet bgs) and HB-20 (11 5 and 19 feet <br /> bgs) consist of silty, clayey soils with some fine grained sands The <br /> percentage of soils passing the number 200 sieve in these samples ranged <br /> from 66 3 to 72 6 in these samples These results are consistent with the <br /> lithologic description of these soils presented in the boring logs for HB-17 <br /> and HB-20 (Appendix B) <br />' The sample collected at HB-17 at 22 feet bgs is indicative of a fine grained <br /> sandy soil All soil from this sample passed the number 4 sieve and 90 9 <br />' percent passed the number 50 sieve Only 22 percent passed the number <br /> 200 sieve These results are consistent with the lithologic description of <br /> this soil presented in the boring log for HB-20 <br /> Based on these sampling results and the lithologic descriptions of borings <br />' previously advanced at the site, the site hydrogeology consists of silty, <br /> clayey soil to depths of approximately 15 to 20 feet bgs, followed by silty, <br /> clayey sands below Some fine grained sands are present in the shallow <br />' soils, however, these were encountered only as small lenses, not <br /> continuous units <br />' The elevated concentrations of TPH-g and BTEX in soil have been <br /> detected at elevations above approximately 20 feet bgs This suggests that <br /> the TPH-g and BTEX present in soil and ground water at the site are <br />' controlled and primarily confined to the silty,clayey soil unit <br />' 22.2 TOC <br /> The results of the TOC analysis are presented in Table 6 and copies of the <br />' analytical results are presented in Appendix A As shown in Table 6, the <br /> TOC concentrations ranged from 160 milligrams per kilogram (mg/kg) to <br /> 1,400 mg/kg The samples collected in the shallower soils contained TOC <br />' concentrations an order of magnitude higher than those collected in the <br /> . deeper soils This is indicative of the higher volatile organic compound <br /> (VOC) concentrations present in the shallower soils These results are also <br />' 5 <br />