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14 August 1991 <br /> GecAudit CV 43C5-1.3 <br /> Page 3 of 4 <br /> MCSW-2, 3, and 4 were non-detect (ND) for TPH-diesel and motor oil <br /> at the required 10 ppm detection limit. These samples were also ND <br /> for TPH-gasoline at the required .5 ppm limit and for BTE&X at the <br /> .005 limit (except for a concentration of toluene of .0054 ppm in <br /> sample MCSW-2. ) The samples were also ND for all chlorinated <br /> hydrocarbon compounds and for PCB's. <br /> All three samples were NQ for cadmium. Concentrations of other <br /> metal ions range from between 5.5 and 8.4 ppm for lead to between <br /> 45 and 85 ppm for chromium, zinc and nickel. <br /> Sample MCSW-1 had residual contamination of 880 ppm TPH-diesel and <br /> minor concentrations of BTE&X compounds. Other contaminants were <br /> ND, except for metals, which were in the range of those from the <br /> other samples. <br /> After reexcavation of the north and west sidewalls, sample MCSW-5, <br /> was collected to confirm the removal of the contamination detected <br /> in MCSW-1. This sample was analyzed for TPH, BTE&X, and total lead. <br /> Both TPH and BTE&X were ND at the required detection limits, and <br /> total lead, at 7.7 ppm, was within the range of other sidewall <br /> samples. <br /> Hydrocarbon concentrations in samples from the stockpiles of <br /> excavated soil ranged from 820 to 4500 ppm TPH-diesel. Metal ions <br /> were in the same range as for the sidewall samples, except lead, <br /> which ranges between 15 and 57 ppm. <br /> Sample GOT1-9 was analyzed for aquatic toxicity according to Title <br /> 22 method Lc-50. Fathead minnow survival rate was 100 %, indicating <br /> that the contaminated soil from the stockpiles is non-hazardous. <br /> CONCLUSIONS <br /> 1. Contamination at this site was restricted to the upper 20 feet <br /> of the soil profile. Ground water is more than 40 feet below <br /> the contamination and is not impacted. <br /> 2. The primary contaminants at this site are diesel fuel, motor <br /> oil, and lead. Concentrations ranging from 820 to 4500 ppm <br /> diesel are present in all samples of excavated soil. <br /> Concentrations reach 610 ppm for motor oil and 57 ppm for lead <br /> in these samples. <br /> 3. Confirmatory samplings around the perimeter of the excavation <br /> f. has confirmed the successful removal of the contaminated soil. <br /> Concentrations of all hydrocarbon compounds are below <br /> detection limits in samples from the four sides and bottom of <br /> the excavation. <br />