Assessment of Atmospheric Metal Depositions in the Industrial Areas of the Southwest of Nigeria

Industrial wastes and discharges have been reported to cause environmental pollution. Lagos and Ogun states house many industries which are assumed to have impacted the states. It is in respect of these that the atmospheric metal deposit of Lagos and Ogun industrial areas, southwest Nigeria were assessed to determine the extent of air pollution of these areas. 100 moss samples were collected from the industrial areas of these two states and were digested using Nordic guidelines and the As, Cd, Cr, Pb, Ni, Cu and Ag contents determined by Atomic Absorption Spectrophotometeric method. Data generated were statistically analysed with Analysis of Variance and the means separated with Duncan Multiple Range Test. It was found that Ogun state was more polluted with Cd, Ni and Cu, Lagos state had more of Pb while the Cr, Ag and As concentrations of the two areas were statistically the same. Moreover, the concentrations of Ag, As and Cr were less than 1mg/l while those of Cd, Cu, Ni and Pb were less than 10mg/l. These metals contributed differently to the pollution of the study areas. It was further found that the highest concentrations of Pb (9.16mg/l), Ag (0.07mg/l), Cr (0.32mg/l) were found in Mile 2, Ojota and Mile 2 respectively in Lagos while the least concentrations were found in Aiyepe, Ogun state. In the same vein, the highest concentration of As (0.31mg/l), Ni (98.32mg/l), Cu (7.76mg/l) and Cd (8.70mg/l) were recorded in Agbara, Attan-tta, Sagamu and Aiyepe respectively, all in Ogun state. The least values were found in Aiyepe (0.04mg/l), Ikeja (6.54mg/l), Mile 2 (5.83mg/l) and Ojota (1.85mg/l) respectively. However, all these heavy metals were present in concentrations greater than the recommended limits of Federal Environmental Protection Agency and European Communities and this suggest that the study areas are highly polluted. It is hoped that the results of this study would inform the Government and the citizens of the study areas that their environments are polluted with heavy metals. This would certainly help in taking proactive steps that will help to reduce the pollution load.Keywords: Air quality, biomonitors, anthropogenic, environment, passive biomonitoring, exudate

Heavy Metal Uptake Responses in Plants Grown on Crude Oil-Polluted Soils as Prospects for Phytoremediation

The demand and utilization of petroleum products have re-energized its exploration and exploitation globally and this upsurge in world production, refining and distribution of petroleum products have brought with it various problems of environmental pollution, which have effects on the ecosystems. Twenty (24) polyethylene pots each containing 7 kg of sandy loam soil mixed with 50 ml of crude oil, were arranged in the Botanical garden of the University of Ilorin, Nigeria, to assess their ability to phytoextract heavy metals in Crude oil-polluted soil. Seeds of Amaranthus hybridus L., Tithonia diversifolia , Abelmoschus esculentus L. and Zea mays were sown in polyethylene containers containing 7 kg of contaminated or Control soil. The containers were arranged in a complete randomized design. Plants were left to grow for two months with regular watering. Plants were harvested, separated into roots and shoots and oven-dried to constant weight. The experimental plants have been able to reduce the concentration of Cu in both soils by about 45% to 85%, Cr in the soil by 92.08% to 96.72%, as the residual concentration varied between 66.00 mg/kg and 99.00 mg/kg, Cd in the soil was reduced to 4.00 mg/kg and 17 mg/kg which represented 96.8% and 86.4% reduction. Tithonia had the highest Pb reduction in crude oil-polluted soil. Ni concentration was reduced by 85.84% by Tithonia planted in crude oil-polluted soil, 94.59% by Amaranthus hybridus planted in Control soil. These show that all the test plants were good phytoextractors of the metals