Heavy Metal Concentration in Soil Irrigated with Ex- Tin Mining Ponds Water, Bokkos L.G.A Plateau State, Nigeria

Abstract:

Metal contamination issues are becoming increasingly common in Nigeria and elsewhere, with many documented cases of metal toxicity in mining industries, foundries, smelters, coal-burning power plants and agriculture. The purpose of this study is to analyse for the concentration of selected heavy metal (Pb, Cu, Cd, Zn, Cr, Fe, Mn and As) of the soils on which the crops were grown, using atomic absorption spectrometry (AAS). The following concentrations (mg/Kg) of the metals were found in the soil samples irrigated with tin mining pond water: Pb (45.4 – 58.9), Cu (20.0 – 28.5), Cd (0.77 – 1.21), Zn (35.7 – 53.5), Cr (17.9 – 22.9), Fe (507 – 618), Mn (35.7 – 48.0) and As (68.3 – 137) and in rainy season: Pb (40.2 – 47.3), Cu (21.7 – 29.2), Cd (0.55 – 1.13), Zn (26.5 – 39.3), Cr (5.32 – 9.65), Fe (563 - 584), Mn (52.0 – 71.4) and As (47.5-129). The general trend of the geoaccumulation of metals in both dry and – rainy season is Cd ˃ Cr ˃ Pb ˃ Zn ˃ As ˃ Cu ˃ Fe ˃ Mn and Cd ˃ Pb ˃ Cr ˃ Zn ˃ Cu ˃ Mn ˃ Fe ˃ As, respectively. Soils collected during dry season from the study sites shows sequence of enrichment in descending order as Cd > Cr > Cu > Pb > Fe > Zn ˃ As ˃Mn and Cd > Zn > As > Pb > Cu > Fe ˃ Cr ˃ Mn, The study revealed that tin mining pond water increases the concentration of metals in the soil which are subsequently absorbed by the plants.