Assessment of Heavy Metal Contamination and Potential Ecological Risk in Water and River Sediments from Moboma Artisanal Gold Mining Sites in Southwest Central African Republic

The study revealed high concentrations of cadmium (Cd), mercury (Hg) and uranium (U) in the tributary streams of the Lobaye river in the Moboma region. The results of mathematical models of sediment contamination suggest that anthropogenic activities may be the main sources of heavy metal pollution, which may come from gold mining activities. All the watercourses present a considerable ecological risk index. The effects of this pollution are devastating. Heavy metals, such as mercury, accumulate in sediments and bioaccumulate in the food chain, affecting not only aquatic fauna, but also the human communities that depend on these resources for their livelihood. The contamination of water resources by gold mining calls for effective decontamination solutions. Among the techniques available, media filtration, in particular the use of zeolite bricks, stands out as an inexpensive option that can be easily adapted to the CAR. Thanks to their porous structure and ion exchange properties, these local materials effectively trap heavy metals such as mercury, lead and others. This simple, cost-effective filtration system offers a sustainable alternative to costly chemical methods. By incorporating this technology, local communities can reduce the toxicity of their water resources while minimising environmental impacts.