Effects of Crude Oil Pollution on the Morphology, Growth and Heavy Metal Content of Maize ( Zea mays   Linn.)

This study was designed to investigate the effect of crude oil pollution on the morphology, growth and heavy metal content of maize (Zea mays L.) by analyzing selected physicochemical parameters and heavy metals in soil samples and plant parts using standard field experimental methods. Results from this study show that all the growth parameters of Zea mays planted in the polluted soil were adversely affected by crude oil pollution. The highest mean height for treatments 50 ml, 100 ml and 150 ml were 33.54 cm, 31.34 cm and 27.44 cm respectively while that of the control was 87.58 cm. The pH of the soil increased as the volume of the crude oil increased. Chlorophyll content of the Zea mays leaves reduced with increase in the volume of crude petroleum. Of the plant parts examined, root had the highest content of chromium (Cr) with 0.22 ppm (150 ml), nickel (Ni) with 0.46 ppm (150 ml), lead with 0.06 ppm (150 ml) and cadmium (Cd) with 0.02 ppm (150 ml) while the highest copper (Cu) value of 0.28 ppm (150 ml) was recorded in the leaves (150 ml). Heavy metals concentration significantly increased (P < 0.05) with the increase in volume of crude oil pollution. This study has shown that crude oil polluted soil brings about reduction in the growth, yield and leaf chlorophyll of maize plant. Coupled with increasing heavy metal concentration, this could lead to scarcity and safety concerns in maize consumption in areas impacted by crude oil pollution.