Speciation and Spatial Distribution of Trace Metals in Sediments Around Gold Mining Areas in Northern Côte D’Ivoire

Abstract The purpose of this study was to investigate the spatial distribution, possible sources, and potential ecological risks associated with traces metals Cu, Mn and Ni in sediments around gold mine areas in northern Côte d’Ivoire. The sampling was conducted in industrial and artisanal and small-scale gold mining sites in Korhogo and Tengrela. Analysis of variance was performed to ascertain spatial differences. The possible sources of pollution were identified using the enrichment factor, principal component, and hierarchical cluster analysis. Trace metals Cu, Ni and Mn concentrations in sediments did not vary across the stations. The same spatial mapping distribution trend was observed for Ni, while those of Cu and Mn differed among the stations. The geoaccumulation index indicated low to moderate contamination of Cu, Mn and Ni at Korhogo and Tengrela. The results of principal component and hierarchical cluster analysis indicated that Cu, Ni, and Mn were generated both by anthropogenic and natural inputs, which were confirmed by the enrichment factor. The potential ecological risks indicated that Cu, Mn and Ni could pose low risk to organisms at Korhogo and Tengrela. This study provides first trace metals data in sediments across Korhogo and Tengrela gold mine areas. The sequential extraction procedure proposed by the Community Bureau of Reference (BCR) showed that a major portion (between 59.68 to 79.22 %) of Cu, Ni and Mn is highly associated with the residual fraction, showing their low mobility.