Clay Minerals in Nigeria Mine Waste: Sorption, Mobility and Stabilization of Contaminants: A Review

Nigeria's mining industry with lead-zinc deposits near the Benue Trough basin and gold deposits in Zamfara is a huge contributor to the nation's economy but creates serious environmental impacts (Okere, 2023). Unchecked artisanal and small-scale mining (ASM), as evidenced by Zamfara lead poisoning tragedy, has resulted in massive soil and water pollution with harmful metals. In this review, indigenous clay minerals; smectite, kaolinite, and chlorite hold promise as low-cost but effective, sustainable agents for remediating mine waste. These clays are ubiquitous throughout Nigeria's geographical domains (Adekiya et al., 2024; Odigi, 1994; Porrenga, 1966) and have structural and physicochemical properties to facilitate contaminant sorption and stabilization. Smectite's high cation exchange ability increases heavy metal retention (Osuna et al., 2019), kaolinite favours heavy-element surface complexation such as arsenic (Caporale & Violante, 2016), and chlorite assists stabilization with a long duration. In view of Nigeria's climate with large parts being tropical to semi-arid, clay contaminant interaction knowledge is important to formulate effective but locally relevant remediation solutions and inform environmental policy to ensure reductions in ecological and health hazards.