Water pollution and treatment challenges from artisanal gold mining in Ghana: A decade review (2014–2024)

Artisanal and small-scale gold mining (ASM) remains a major driver of water pollution in many tropical developing economies. This review synthesizes scientific and grey literature published between 2014 and 2024, to examine the nature of water pollution, treatment challenges, and governance constraints associated with unregulated artisanal gold mining in Ghana. The reviewed studies report frequent exceedances of World Health Organization (WHO) drinking-water guidelines for mercury, cyanide, and other heavy metals such as arsenic, lead, and cadmium. The levels are of extreme concentrations in impacted river basins, mine effluents, and sediments associated with ASM. The high sediment loads (commonly exceeding 2000–12,000 NTU) coupled with extensive deforestation, have destabilized aquatic systems and placed severe stress on municipal treatment plants designed for substantially lower turbidity and contaminant levels. Conventional coagulation–filtration processes are widely reported to be ineffective under these multi-contaminant conditions. Emerging hybrid treatment approaches such as ceramic–carbon filtration, biochar adsorption, re-purposed membrane systems, and constructed wetlands have reported removal efficiencies of approximately 75–99 % in laboratory and pilot-scale studies. Improved techniques to minimize fouling, cost, and maintenance requirements should be undertaken to ensure filed deployment. Remediation efforts are also further hindered by Institutional fragmentation, limited environmental monitoring, and weak community participation. This review identifies critical gaps in pollutant speciation, field-scale technology validation, data integration, and policy coordination; proposes an integrated framework combining low-cost hybrid treatment technologies. The findings offer transferable insights for improving water quality management in ASM regions across sub-Saharan Africa and comparable contexts.