Iron Ore Deposit and Its Tailing Impact on the Toxic Metal Level of Neighboring Agricultural Soils

Aim: This is one of our mineralogical study series aimed at the preliminary characterization of iron ore and its neighboring farmland soils, with focus on ore impact on soil quality, toxic metals concentration and the geo-accumulation status of pollutants.

Methodology: Mineral (Iron ore) samples and ore rich soils from neighboring farmlands, coded as I-Soil, I-soil-FLA, I-soil-FLB and I-soil-FLC were collected from Itakpe, Kogi State in North Central Nigeria. Samples were qualitatively characterized using Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM) and Ultraviolet Visible (UV-Vis) spectrometer for functional group analysis, micro-structural morphology and spectral profile respectively. Physico-chemical parameters were investigated following routine classical (wet) chemistry procedures. Levels of toxic metals including Iron (Fe), Lead (Pb), Manganese (Mn), Cadmium(Cd), Chromium (Cr), Zinc (Zn), Nickel (Ni) and Copper(Cu) in both ores and soils were estimated using Atomic Adsorption Spectrophotometer (AAS).

Results: The iron ore SEM images appeared compact with irregular shapes. UV –Visible Spectral shows that the mineral has possibly leached from the parent ore to the nearby soils at similar range. Highlights of this studies shows that the level of metals in farmland soils are statistically significant (p < 0.05) when compared with those of the mineral ores, and insignificant (p > 0.05) when compared to acceptable or threshold limits provided by the USEPA and WHO. Relying on geo-accumulation index values, this study classified the farmland soil with regards to the iron load as “extremely contaminated”. Investigated soil samples are “strongly contaminated” with Pb, “moderately contaminated” with Mn and Zn and “uncontaminated” with Cd and Cu.

Conclusion: The parametric factors of the soil samples, soil quality and metal distribution among ore-rich soils showed levels that could be linked to both geogenic and anthropogenic activities. Furthermore, the farmland soil’s toxic metal levels in the study area might be enriched by either mine tailing from the mineral ore depot or anthropogenic. Our recommendation is strictly on continuous environmental impact assessment, environmental monitoring, environmental auditing and environmental awareness campaign.