Effect of crude oil pollution on heavy metal contents, microbial population in soil, and maize and cowpea growth

Abstract

The effect of crude oil pollution on heavy metal content in the soil, microbial population, and growth performance of maize and cowpea was investigated. The heavy metals determined were lead, cadmium, iron, nickel, zinc and copper. Microbial population and growth performance of maize and cowpea in both polluted and unpolluted soils samples were evaluated. Results showed that higher concentration of heavy metals was observed in all crops planted in polluted soil, polluted site vegetation and soils. The total heterotrophic bacteria was 89% lower in the polluted soil than in the unpolluted soil while fungi was 78% lower in the polluted soil when compared to the unpolluted soil. However, hydrocarbon utilizing bacteria and fungi was 22% and 24% higher in the polluted soil than in the unpolluted soil respectively. Maize and Cowpea performed poorly in polluted soil when compared with unpolluted soil as evidenced in the growth parameters measured for both crops.