Total Petroleum Hydrocarbon and Heavy Metal Reduction: A Case Study of Enhanced Degradation Potential of Animal Waste by Fungal Isolates

This study is conducted to determine the role of poultry litter and cow dung in enhancing the degradation of diesel in contaminated soils by fungal isolates. The treatment sets were used for soils with three levels of diesel pollution (50 ml, 100 ml and 150 ml). The microbiological properties, total petroleum hydrocarbon content and heavy metals were analyzed for six months using standard analytical procedures. The highest and lowest levels of total petroleum hydrocarbon utilization percentages were observed for C1 as (98.5 %), soil with 50 ml diesel, amended with poultry and cow dung, and also for Control 1 as (31.6 %). The results of heavy metal analysis revealed Pb having the highest value of 3.20 mg kg^-1 recorded for C3, soil with 150 ml diesel amended with poultry litter and cow dung in the month of July, 2016; Cr had its highest value of 2.8 mgkg^-1 recorded for B3, soil with 150 ml diesel amended with cow dung in July, 2016, and Fe had its highest value of 182 mg kg^-1for C3 also in the month of July, 2016. The results of the total heterotrophic and hydrocarbon-utilizing fungal counts ranged from 22.0±2.0 to 42.5±2.5 x10^4 cfu/g for C1 and B3 and 24.0±2.0 to 51.0± 2.0 x10^4 cfu/g for C3 and B1, soils with 50 ml diesel amended with cow dung respectively. Seventeen fungal species were isolated. Aspergillus spp. had the highest frequency of occurrence, 31.69 % and the least percentage of frequency of occurrence was recorded for Candida albicans (0.7 %) and Botrydiplodia sp. (0.7 %). This study stresses the enhanced potential of fungal population in the reclamation of diesel-contaminated soils.