ASSESSMENT OF HEAVY METAL BIODEGRADATION POTENTIALS OF PALM BUNCH ASH IN DIESEL OIL POLLUTED SOIL

Diesel oil pollution is a major challenge in most developing countries like Nigeria. This study was carried out to ascertain the possibility of remediating diesel oil polluted soils using palm bunch ash. Samples of garden soil with no history of diesel oil pollution were spiked with 100mL of Bonny Light diesel oil and left for two weeks to simulate a condition of major spill before adding different weights of palm bunch ash (0, P+NOPBA, 50g, 150g, 250g and 350g). 1g from each treatment was collected monthly and subjected to laboratory analysis using standard analytical methods for soil selected heavy metals contents using AAS. Preliminary results revealed alteration of chemical properties of soils, elevated heavy metals levels two weeks after spiking indicating that the soil sample had undergone slight alteration. There was a dose dependent decrease in heavy metal content of the diesel oil polluted soils with time. Mean concentration of Zinc ranged from 95.7mg/kg to 7.45mg/kg; 9590.5 to 99.83 in Fe; 3.5mg/kg 1.4mg/kg Cu; 1.45mg/kg to 0.06mg/kg Cd and 10.90mg/kg to 0.05mg/kg in Pb. Overall, net reduction in heavy metals was very low in soil left under natural attenuation (polluted untreated soil) than treated soils. This study has revealed a marked degradation of the heavy metal content of soil which indicated that palm bunch ash could be used for remediation of diesel oil polluted soil. It is recommended that palm bunch ash be replaced with conventional fertilizer in restoration of crude contaminated soil.