Performance Evaluation of Six Microorganisms Utilized for the Treatment of Lead Contaminated Agricultural Soil

Abstract

This work focused on the ability of six indigenous microorganisms (Arthrobacter nicotiniae, Bacillus substilis, Klebsiella pneumoniae, Proteus mirabilis, Trichophyton interdigtae and Onychocola canadensis) isolated from contaminated agricultural soil obtained from Ishiagu forest in Ebonyi State, Nigeria for the removal of lead (Pb) ion from the soil. The weights of organisms, nutrient dosage, temperature, pH and stirring frequency were optimized for the removal of the metal ion from the soil. The data revealed that Bacillus subtilis, Klebsiella pneumoniae and Arthrobacter nocotiniae were found to reduce the metal concentration below recommended standard at time 14 days with respective efficiencies of 58.25 %, 60.64 % and 60.80 % at the 14 days; and 78.25 %, 76.19 % and 79.78 % at time 35 days; while Proteus mirabilis, Onychocola canadensis and Trichophyton interdigtae were found to reduce the metal concentration at time 21 days with respective efficiencies of 51.74 %, 44.65 % and 48.08 % at time 21 days; and 59.67 %, 51.13 % and 55.27 % at time 35 days. The study showed that the organisms can be utilized to remove Pb ion from the contaminated soils. Arthrobacter nicotiniae showed the greatest removal capacity with time, followed by Bacillus substilis, and then Klebsiella pneumoniae; before Proteus mirabilis, Trichophyton interdigtae and Onychocola canadensis in that order.

Keywords: Bioremediation, contaminated soil, removal efficiency and lead