Assessment of Heavy Metal Contamination in Mining Areas of North-Central Nigeria
The study focused on the measurement of the concentration of heavy metals, known as potentially toxic elements (PTEs), in soil samples obtained from beryllium minefields and gold minefields in Ifelodun and Moro respectively, Kwara, Nigeria. The potentially toxic metals comprise Arsenic (As), Zinc (Zn), Cadmium (Cd), Nickel (Ni), Iron (Fe), Chromium (Cr), Manganese (Mn), Magnesium (Mg), Lead (Pb) and Copper (Cu). The soil samples were collected in duplicates using a soil auger and packaged in labelled polyethylene bags to prevent material reaction.
The samples obtained from the locations underwent a process of open room drying to obtain constant dry weight samples that are moisture free, pulverised and put through a 1 mm sieve. One gram of the samples was placed in a digestion flask and three (3) ml of HNO3 and nine (9) ml of HCl were added. The mixture was then heated on an electrical heating plate for fifteen (15) minutes until all brownish fumes were expelled, confirming the completion of the digestion of the samples. The digested solution was cooled and then filtered into a standard flask and then diluted with distilled water and then analysed using the Atomic Absorption Spectrophotometer.
The presented work has revealed that the analyzed values of the heavy metals exhibit a symmetric distribution. The risk evaluation of the toxic elements was initiated by estimating the chronic daily intake (CDI) of each of the metals through the possible exposure pathways including ingestion, inhalation, and dermal contact. Additionally, the Carcinogenic and Non-Carcinogenic Risk Assessment were calculated using the incremental lifetime cancer risk (ILCR) and the hazard index (HI).
Monte Carlo simulation was employed to inspect the probable cancer risks associated with the exposure to the toxic elements. The study findings have indicated that the cancer risk is high for both locations due to the presence of these heavy metals in the environment.
The authors Muyiwa Michael OROSUN, Samuel O. INUYOMI, Hitler LOUIS, and Emmanuel Olusegun EHINLAFA performed the analysis, while Mojisola Rachael USIKALU, Hussein K. OKORO, Maxwell OMEJE, and Kayode John OYEWUMI ensured supervision and final editing of the manuscript. The authors have declared no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this article. The authors also acknowledged the support received from TETFund via Institutional based research (IBR) and Covenant University.
