RESUMEN
An assessment was conducted on soils of Ibadan metropolis using geochemical approach in order to establish the concentration of heavy metals and develop geoaccumulation index maps. Petrographic studies and X-ray diffractograms showed that soils of Ibadan were derived from the weathering of the bedrocks. The concentrations of Cu, Pb, and Zn were found to be greater in soils more than the background. Positive correlation occurred between Cu, Pb, and Zn indicated a common anthropogenic source in the soil while Mn, Cr, and Ni were found to be naturally enriched. The geoaccumulation index maps revealed significant enrichment factor (Ef 20) and index of geoaccumulation (Igeo) beyond class four (heavily contaminated) for Cu, Pb, and Zn in densely populated and industrial areas, whereas Cd is enriched in sparsely populated areas, agricultural areas and a few spots in densely populated areas.
Asunto(s)
Metales Pesados/análisis , Contaminantes del Suelo/análisis , Monitoreo del Ambiente , Sedimentos Geológicos/análisis , Humanos , Nigeria , Población UrbanaRESUMEN
The aim of this study was to assess the heavy metal content of the dust generated by the Sagamu cement factory and its attendant health hazards on the immediate environment, especially on the inhabitants of the area. A total of 25 samples were collected and analyzed using inductively coupled plasma-optical emission spectrometry. Records of medical ailments associated with heavy metal toxicity were also compiled from the Obafemi Awolowo Teaching Hospital situated in the town. The results for some of the selected heavy metals showed the following pattern: limestone: Cd (n.d.-1.7 ppm), Pb (42-48 ppm), Cu (3.0-11 ppm), Zn (7.0-53 ppm) and Ni (3.0-8.0 ppm); shale: Cd (0.3-1.1 ppm), Pb (17-22 ppm), Cu (2.0-11 ppm), Zn (17-147 ppm) and Ni (3.0-18 ppm); dusts: Cd (0.5-0.7 ppm), Pb (32-52 ppm), Cu (2-16 ppm), Zn (5-152 ppm) and Ni (2-17 ppm); soils: Cd (0.5-1.1 ppm), Pb (28-49 ppm), Cu (22-35 ppm), Zn (43-69 ppm) and Ni (13.0-17 ppm). High levels of heavy metals were found in the rocks and soils. We propose that the high levels of metals in the dust and soil were acquired from the raw materials used by the cement factory and from active industrial discharge from this same factory. Medical records and the current health situation of the local residents in the study area reveal that there have been increases in the prevalence of diseases linked to heavy metal toxicity in the environment, especially those related to dust generation.