Environmental Impact of Mining New Insights from Risk Assessment of Potentially Toxic Elements due to Mining Activities at Ajaokuta, Kogi State, Nigeria

• Published in: Geology and Natural Resources of Nigeria pp. 520 - 531
• Main Authors: Orosun, Muyiwa Michael, Ajibola, Taiye Benjamin, Olawoyin, Habeeb O., Adenekan, Moshood O., Salawu, Naheem Banji, Akinyose, Fisayo Cornelius, Onumejor, Charity Adaeze, Dawa, Saidu A.
• Format: Book Chapter
• Language: English
• Published: United States CRC Press 2025; Taylor & Francis Group
• Edition: 1
• Subjects: Non-carcinogenic Risk; Groundwater; Potentially Toxic Elements; Atomic Absorption Spectrometry; Carcinogenic Risk
• ISBN: 9781032594866; 1032594861; 9781032594859; 1032594853
• DOI: 10.1201/9781003454908-30

Groundwater, one of the primary sources of drinking water, is constantly being polluted by potentially toxic elements (PTEs) due to mining and smelting activities. This study evaluates the health risks associated with 10 PTEs (Mg, Mn, Ag, Zn, Cd, Pb, Cu, Fe, As, and Cr) that may be present in groundwater due to mining activities in Ajaokuta, Kogi State, Nigeria. Twenty-five topsoil and 60 groundwater samples collected within and outside the study area were analyzed by Atomic Absorption Spectrometry (AAS). The concentration levels of the elements studied varied, with generally higher values observed in samples collected within the mining area compared to those collected outside of it. The concentration of these PTEs in the topsoil decreased with increasing distance from the pollution source epicenter. In the water samples within the mining area, the mean concentrations of Fe, Pb, Cd, As, and Cr exceeded the values recommended by the World Health Organization (WHO) and other regulatory bodies, posing health risks. The estimated mean Hazard Quotient (HQ) and Hazard Index (HI), used to assess the non-carcinogenic health risks to residents through ingestion, were below acceptable limits. However, the estimated carcinogenic health risks (ILCR) for most of the carcinogenic PTEs exceeded the acceptable limit of 1 × 10-6 and posed serious health risks. The results of this study will be useful in implementing protective measures to prevent human health risks associated with exposure to these PTEs.