Hydrogeochemical characterization and risk assessment of potentially toxic elements in water sources around Ibese quarry, southwestern Nigeria

Abstract

Mining contributes to escalating global concerns regarding water pollution and human health. This study investigates major ions and potentially toxic elements (PTEs) in water sources around a limestone quarry for irrigation suitability and public health. Samples were analyzed using standard methods and assessed with established pollution, ecological, and health risk models. pH values ranged from 2.61 to 8.16, indicating acidic to slightly alkaline waters. Calcium and HCO 3 were the dominant ions, with Mg-HCO 3 as the prevailing water type. Most parameters are within the WHO guidelines, except for pH, As, Cr, Ni, and Pb in some samples. Irrigation indices SAR (<10), MAR (4.37 – 25.89 %), KR (0.06 – 0.37 %), Na% (5.16 – 16.57), and PS (43.38 – 162.75) suggest overall suitability, though elevated potential salinity (PS up to 162.75) suggested possible long-term soil salinization. Pollution indices (CF, Igeo, PN) showed low to moderate contamination, and ecological risk (PERI = 39.45) was classified as low. However, human health risk assessment revealed ingestion as the dominant exposure pathway, with As and Pb posing carcinogenic and neurotoxic risks, and Cr and Ni showing genotoxic and reproductive toxicity potential. Treatment is recommended before domestic or industrial use. The findings highlight the need for continuous monitoring, quarry waste water management, and community health surveillance. Integrating hydrochemical data with adaptive water quality governance supports sustainable resource use and aligns with SDG 6 (Clean Water) and SDG 15 (Life on Land).