Accumulation and Contamination of Heavy Metals in Soil and Vegetation from Industrial Area of Ikirun, Osun State, Nigeria (Published)
Samples of soil and vegetation were analyzed for their heavy metal contents using standard methods. Samples were collected around a steel rolling mill along Ikirun, Osogbo road, Osun State. Results of vegetation revealed highest iron concentration (17305.00mg/kg), highest chromium concentration (1088.00mg/kg), highest nickel concentration (303.40mg/kg), and highest lead concentration (38.88mg/kg) at VG 7. Soil analysis showed highest iron concentration at SS3 (29895 mg/kg), highest cobalt concentration at SS6 (510 mg/kg), highest nickel concentration at SS6 (882 mg/kg), highest lead concentration at SS7 (2525 mg/kg) and highest chromium concentration at SS6 (2935 mg/kg). This suggests that the area was grossly contaminated mostly with iron, chromium, lead and nickel especially in soil. Plant concentration factor was in the range 0.03 – 0.63 for iron, 0.10 – 0.62 for cobalt, 0.01 -0.76 for nickel, 0.00002 – 0.02 for lead and 0.09 – 0.95 for chromium. Plant absorption of heavy metals from soil was in the order Cr>Ni>Fe>Co>Pb. Integrated pollution index of soil showed low to extreme high level of pollution. Statistical significant differences were observed between means of heavy metals in study area and control site. Strong positive correlations were observed between pairs of metal in vegetation and pairs of metal in soil. Inter-element correlations were however observed to be weak between the two media. Levels of metals in control sample were not as high as levels obtained at the steel rolling mill.
Keywords: Heavy Metals, Integrated Pollution Index, Plant Concentration Factor, Soil, Vegetation