ABSTRACT
Crude Oil spills are one of the main sources of environmental contamination in Nigeria especially in the Niger Delta. Daily oil spill incidents have polluted the air, soil, natural vegetation, farmlands, sources of drinking water, and fishing creeks. Hydrocarbon contaminants have become a global concern due to their long-term adverse effects on soil ecosystems and human health. A 16 weeks study was carried out to determine the phytoremediation ability and in vitro nutritive value of Cynodon nlemfuensis and Pueraria phaseoloides planted on Crude oil con taminated soils. Four treatments, arranged in a completely randomized design were used in this study. Treatment 1 was made up of 10 replicates of Cynodon nlemfuensis planted in a bucket containing 1 kg of soil contaminated with 50 g of crude oil, Treatment 2 comprised of 10 replicates of Cynodon nlemfuensis planted in a bucket containing 1 kg of uncontaminated soil. Treatment 3 comprised 10 replicates of Pueraria phaseoloides planted in a bucket containing 1 kg of soil contaminated with 50 g of crude oil, and Treatment 4 comprised 10 replicates of Pueraria phaseoloides planted in a bucket containing 1 kg of uncontaminated soil.
Observations during the course of this study includes: contaminated Cynodon nlemfuensis was observed to have reduced growth rate at the first four weeks, but uncontaminated Cynodon nlemfuensis had a better growth rate and overall performance. Contaminated Pueraria phaseoloides was observed to have stunted growth, yellowing and wilting of leaves, scanty leaves and death of plants within the first four weeks after planting, while uncontaminated Pueraria phaseoloides was observed to have a norm al growth rate. At the end of the study, the final dimensions of plants were taken and plants were harvested, weighed fresh and oven dried at 70”C until a constant weight was attained, the dried samples were thereafter milled and stored in air-tight containers. The chemical compositions of the soil and plant samples were determined alongside the in vitro Nutritive values (%) were determined and the data obtained analyzed statistically. Results revealed that Heavy metals, Pb, Cr and Cd contents of the soil contaminated with crude oil was higher than uncontaminated and the contaminated invitro fermentation value for C. nlemfuensis was higher and significant (P>0.05) from uncontaminated, while for P. phaseoloides, uncontaminated samples value was higher than contaminated. The results clearly demonstrated that C. nlemfuensis and P. phaseoloides will provide an easy tool for phytoremediation with crude oil.
