Hydrogeological Impact of Gold Mining, Contaminant Flow Patterns and Groundwater Quality Assessment in the Kambele Mining Area, Eastern Part of Cameroon

Abstract

Gold mining activity is a source of income in many areas worldwide, especially in developing countries where it is often practiced illegally using unsafe techniques. In the Kambele area, artisanal and small-scale gold mining (ASGM) is widespread, and gold recovery relies on the use of toxic substances such as mercury (Hg), posing a threat to both the environment and human health. This study assesses aquifer flow directions and the impact of ASGM on the shallow aquifer in the Batouri gold district, specifically in the Kambele mining sites, where limited scientific studies have been carried out. Piezometric measurements were conducted on 36 wells, and 7 underground water samples were collected from the Kambele locality. Two trace elements (mercury and cyanide) and ten major ions were analyzed using the Atomic Absorption Spectrometer and Ion Chromatography techniques. The piezometric map revealed varying groundwater flow directions at different localities: Kambele 1 had a flow direction from west to east, while Kambele 2 and 3 had flows from east to west. Analysis showed that 72% of the samples had Hg concentrations ranging from 0.0010 mg/l to 0.0027 mg/l, and 57% of the samples had CN concentrations ranging from 0.0011 mg/l to 0.0025 mg/l. All samples had Hg and CN concentrations below the World Health Organization (WHO) guidelines for water quality, which are 0.006 mg/l for Hg and 0.007 mg/l for CN. Additionally, all major ions analyzed were within WHO guidelines. Hydrometric degree (hardness) and Sodium Adsorption Ratio (SAR) values indicated that the water is fresh and suitable for agricultural irrigation. This research highlights the importance of understanding groundwater flow patterns and contaminant transport pathways to mitigate the environmental impacts of ASGM and ensure water quality for human consumption and the environment.