Impact of Mining Activities on Water Contamination by Heavy Metals and Cyanide in the Hiré Region, Ivory Coast

Mining activities, both industrial and artisanal, play a crucial role in economic development but often come with significant environmental costs, particularly through water contamination. The Hiré region in Ivory Coast is significantly impacted by extensive gold mining and the intensive use of chemicals in ore processing, posing substantial risks to groundwater quality. While industrial mining is subject to regulations, unregulated artisanal mining practices contribute significantly to environmental contamination. This study evaluates the distribution of potentially toxic elements (PTEs) and pollution indices, including the Enrichment Factor (EF), Heavy Metal Pollution Index (HPI), and Heavy Metal Contamination Index (HCI), in groundwater used for drinking purposes. The focus is on metals such as Pb, Hg, Cd, As, Cr, Fe, Al, Zn, Mn, and cyanide contamination.

Results indicate that arsenic, iron, and aluminum concentrations at several sites far exceed international water quality standards, likely due to natural geochemical processes and mining activities. The concentration of potentially toxic elements (PTEs) were generally high, with enrichment factors EF > 1 at the majority of sampled sites. Pollution indices show HPI < 100 and HCI < 50 for over 85% of sampled sites, indicating mild contamination. However, cyanide levels in cyanidation ponds exceeded safe limits by over 5900 times, highlighting critical environmental and health risks.

These findings underscore the importance of monitoring heavy metals, particularly cyanide, in the groundwater of the Hiré zone. Special attention should be given to unregulated artisanal mining and its constant relocation, which can expand the area of contamination. Ultimately, these findings contribute to the development of mitigation strategies and inform policymaking to address water pollution challenges in mining regions globally.