Health Risk Assessment Associated with the Presence of Heavy Metals in Soils Around the Kalsaka Gold Mine, Burkina Faso

Abstract

This study assessed heavy metal concentrations in soils around the Kalsaka gold mine in Burkina Faso and evaluated the associated human health risks for adults and children. Sixteen soil samples were collected from locations surrounding the mine and analysed for chromium, nickel, copper, zinc, arsenic, mercury, and lead using atomic absorption spectrophotometry. Human exposure was estimated through ingestion, inhalation, and dermal contact pathways using standard exposure parameters. The results showed that the mean concentrations of chromium, nickel, copper, arsenic, and mercury indicated contamination in the sampled soils, while zinc remained below the reference limit used in the study. Lead showed localised contamination, with the maximum concentration exceeding the reference value although the mean concentration remained below it. Arsenic showed the highest mean concentration among the measured elements, followed by chromium, copper, zinc, nickel, lead, and mercury. Estimated daily intake values indicated that ingestion was the major exposure pathway, particularly for children. Non-carcinogenic risk assessment showed that the combined risk index exceeded unity for both adults and children, suggesting potential non-carcinogenic health risks associated with exposure to contaminated soils. Children showed higher risk values than adults, indicating greater vulnerability. Chromium and arsenic were the main contributors to non-carcinogenic risk. The estimated carcinogenic risk values were low under the exposure assumptions used in this study. Overall, the findings indicate that soils around the Kalsaka gold mine contain elevated levels of selected heavy metals and that continued monitoring, exposure reduction, and environmental management measures are needed.