Université Félix Houphouët Boigny, Abidjan, UFR des Sciences de la Terre et des Ressources Minières (STRM), Laboratoire des Sciences du Sol, de l’Eau et des Géomatériaux (LSSEG), Côte d’Ivoire
In a context of strong dependence of Ivorian populations on surface water resources, the Mé River occupies a strategic position, particularly for the supply of drinking water to the city of Abidjan. However, this resource is facing a growing threat due to the intensification of artisanal gold mining activities within its watershed. This study therefore aims to assess the impact of these activities on the water quality of the Mé River, with a view toward the sustainable management of this resource.
The methodological approach first involved a physicochemical analysis of the water resource in relation to the World Health Organization (WHO, 2017) guideline values, followed by a qualitative assessment using contamination and pollution indices based on trace metal elements (TMEs).
The results show an alkaline pH (10.2), low mineralization (113.13 µS/cm), and a very high average turbidity (13,115.78 NTU). The analyses also revealed high concentrations of cadmium (Cd; mean: 36.81 µg/L), copper (Cu; mean: 166.72 µg/L), mercury (Hg; mean: 46.31 µg/L), and lead (Pb; mean: 72.5 µg/L), indicating contamination of anthropogenic origin, directly linked to artisanal gold mining activities.
The contamination index shows a decreasing ranking of TMEs as follows: ICM (Cd) > ICM (Pb) > ICM (Hg) > ICM (Cu) > ICM (Mn) > ICM (As). Furthermore, the heavy metal pollution index (HPI) reveals that all analyzed water samples (100%) have an HPI value greater than 100, indicating a high pollution risk and rendering the water unsuitable for use.