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This study determines if the bacterial population has adapted to the contaminant present in the sail <br /> and sludge samples. <br /> The heterotrophic population ranged froth 740 to 100,000 colony-forming units per gram of dry i <br /> soil (CFU/g). Hydrocarbon-degrading microbial densities ranged from less than 120 to 2000 <br /> -�' 4 li <br /> CFU/g. The results indicate that a viable microbial population exists,bn site but it is low. Native <br /> microbial population sizes are listed on Table 2. <br /> 2.4 Microbial Stimulation Test <br /> A microbial stimulation test was performed to determine e if enhanced-in situ conditions will <br /> stimulate growth of indigenous bacteria up to densities that are adequate for biodegradation. <br /> This test involves introducing oxygen or oxygen-plus nutrients to the.'soil slurries created from the <br /> 1 <br /> soil samples. The results determine if oxygen will stimulate activity, and if nutrients provide an <br /> ,I <br /> additional benefit. A positive response is indicated by �i five fold or greater change in microbial <br /> density. <br /> Bacterial densities for the heterotroph population in the Van Den Bergh Foods Company samples <br /> increased by 10 to 1,000-fold after oxygenation in samples SB-I-2B and SB-1-IB respectively, ; <br /> with additional increases of less than one order of magnitude upon nutrient addition. Sample SB- <br /> 1-3B showed no increase after oxygenation but increased by four orders of magnitude upon <br /> i <br /> nutrient addition (Table 3). Hydrocarbon degraders in(samples SB-1-IB and SB-I-2B increased <br /> iM I <br /> by one to two orders of magnitude while sample SB-I-3B increased only slightly with <br /> oxygenation. Samples SB-1-IB and SB-113B increased from two to four orders of magnitude j <br /> respectively upon nutrient addition and sample SB-1-2B increased less than an order of <br /> magnitude. These increases in both the heterotrophic and hydrocarbon degrading populations <br /> suggest that soil aeration and nutrient amendment will stimulate microbial activity. <br /> j <br /> 'I R ! <br /> VanDa&kw&114 3 �! <br /> �� .li <br />