ABSTRACT
Dumping of waste on the land has caused soil and water contamination in the environment. A study on the analysis of soil and surface water characteristics due to municipal waste is indispensible to the sustenance of the environment and human health. This study investigated the impact of open dumpsite on the quality of soil and surface water around Onibu-Eja Area. Thirty two (32) soil samples were collected by method of random sampling. Each of the sampling point had four (4) soil samples collected at the depth of 0 – 10cm, 10 – 20cm, 20 – 30cm and 30 – 40cm. Seven (7) surface water samples were also collected. Heavy metals which were known to be toxic to human and the environment were examined in the soil which includes Zinc, Lead, Iron, Chromium, Cadmium, Copper and Nickel. The physico-chemical and heavy metal parameters of the surface water were also assessed using Atomic Absorption Spectrophotometry (AAS) and Titrimetric method. The result revealed the following concentration: Iron (208.48mg/kg), Lead (4.02mg/kg), Chromium (0.74mg/kg), Zinc (0.41mg/kg), Copper (0.070mg/kg) and Cadmium (0.017mg/kg) exceeded values at the control point Iron (160.36mg/kg), Lead (2.06mg/kg), Chromium (0.57mg/kg), Zinc(0.24mg/kg), Copper (0.034mg/kg) and Cadmium (0.011mg/kg) for soil. The concentration of the heavy metal at the top sample of the different soil sampling point taken at the dumpsite show relatively higher concentration compared with bottom samples implying that the elements have not been sufficiently leached to the subsurface. The decreasing order of the heavy metal contents of the dumpsite soil is Fe > Pb > Cr > Zn > Cu > Cd. A strong degree of association was found to exist between most of the heavy metals especially Zn and Pb, Zn and Cr, Zn and Cd, Zn and Cu, Zn and Fe, Pb and Cd, Pb and Cr, Pb and Cu, Pb and Fe, Cr and Cu, Cr and Cd, Cr and Fe, Cd and Cu, and Cd and Fe through the use of statistical tool of Pearson’s Correlation Coefficient. The physico-chemical parameters analyzed for all surface water agree with the international World Health Organization (WHO) 2007 and Nigerian Standard for Drinking Water Quality (NSDWQ) 2007. The mean Lead, Iron, Chromium and Cadmium content in the surface water ranged from 2.79mg/l,93.12mg/l,0.57mg/l and 0.072mg/l all exceeded World Health Organization (WHO) standard for drinking water. This shows that the waste dump which is rich in heavy metal interacted with the soil and surface water there by contaminating it. Therefore, there is need for adequate waste management practice to ameliorate the impending health risk from heavy metals.
