Comparative studies of biostimulation using local materials and phytoremediation in the mitigation of crude toxicity on tropical soil of the Niger-Delta of Nigeria were carried out. 5% pollution level of crude oil were done alongside the control. Remediation treatments were done after one week of pollution using the following materials: Batch A : 20g of NPK 15:15:15; batch B: 50g of poultry dung; batch C: 5 seeds of Vigna unguiculata grown on the polluted soil (phytoremediation); batch D: control (pollution but no remediation); and batch E: double control (no pollution and no remediation treatment). Soil analyses result indicated that the different remediation treatments have potentials to ameliorate crude oil toxicity at different degrees because of their ability to increase the nutrient content and decrease the total hydrocarbon content of the soil. There was no statistical difference in the soil pH, Zinc and Copper contents between and within treatments throughout the study period. Highest crude oil biodegradation and improvement in nutrient content of the soil were observed in NPK 15:15:15 and phytoremediation treatments indicating that these are good remedial treatment options in the mitigation of crude oil toxicity. @ JASEM

A study of heavy metal contents in plants and soils in two abandoned solid waste dumpsites alongside the controls located along East-west road (site 1) and Eastern bypass (site 2) was conducted. A systematic sampling approach was used comprising total of 9 sample plots of 4 m 2 each located on 3 line transects. The soil samples were collected at each plot using a soil auger at the depth of 0-15 cm. Dominant plant species were selected, uprooted and collected from each sample plot. Both plants and soil from each sample plot were analyzed for heavy metals [Zinc (Zn), Iron (Fe), Cadmium (Cd) and Lead (Pb)]. The results showed that there was an increase in the concentration of heavy metals in the two dumpsite soils than that of the soils at the control sites. The heavy metal (Fe and Zn) contents in the plants were higher at the dumpsites than control sites while the concentrations of Pb and Cd in the plants were higher at the dumpsite than control at site 1 (East-West road) and higher at the control site than dumpsite at site 2 (Eastern ByPass) respectively. The level of heavy metals transfer for site 1 was in the order: Fe>Pb>Cd>Zn while for site 2 was Fe>Cd>Pb>Zn. Therefore, abandoned solid waste dumpsites contained high concentrations of heavy metals which are later absorbed and accumulated by plants growing at such sites.

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Long-term effects on soil chemical properties and plant composition of a crude oil polluted site were assessed using random surface soil samples and quantitative vegetation data collection methods. Results showed that total hydrocarbon content (542.50±28.58 mg kgG 1 ) and total organic carbon (1.06±0.18%) of polluted site were significantly (p = 0.05) higher than the unpolluted site of 27.90±22.10 mg kgG 1 and 0.73±0.06%, respectively. Plant species composition showed that Aspillia busei and Heterotis rotundofolia were abundant at polluted site and absent in unpolluted site while Panicum maximum and chromolaena odoratum were absent in polluted site. Species diversities records were 0.37 (polluted site) and 0.64 (unpolluted). Aspillia busei recorded the highest frequency of occurrence (90%) and density (28.2 mG 2 ) in the polluted site while Starchytarpheta jamaicensis recorded the highest frequency of occurrence (40%) and Andropogon tectorum the highest density (3.9 mG 2 ) at the unpolluted site. It can be concluded that the effects of crude oil pollution persists for a long time and negatively affect soil chemical properties, plant species composition and species diversity.

This study was carried out to determine the proximate and mineral composition of fresh tubers of 17 African Yam Bean (AYB) accessions. Standard analytical procedures were adopted in the determination of bioactive compounds in the tubers of the different accessions. Data were subjected to descriptive statistics, principal component and clustering analysis. Ash content ranged between 4.59-9.99%, Carbohydrate (46.59-66.52%), Crude fibre (6.93-12.13), Fat (1.06-4.04%), Moisture content ranged between 11.36-21.91% and Protein (4.91-14.50%). The range of mineral content evaluated were: Calcium (1.53-5.82), Copper (10.59-44.93), Iron (63.52-240.48), Magnesium (0.59-2.26), Manganese (42.25-160.01), Nitrogen (0.75-2.23%), Potassium (1.34-5.08), Sodium (0.05-0.22) and Zinc (28.24-106.93. The proximate variables in the tubers significantly (P<0.05) distinguished the 17 AYB accessions. Three distinct clusters were visible. The seven accessions in cluster I had the highest protein, carbohydrate and moisture content. Cluster II had the least mineral content. Accessions with the highest fat and mineral content were grouped in cluster III. Food, nutritional and medicinal values inherent in AYB tubers is high and promising, its utilization in human and livestock feeds is greatly encourage. Keywords: Accessions, African yam bean, diversity, proximate analysis, tubers