Preliminary stream sediment geochemical exploration for base metals and other elements in terms of source apportionment and contamination status of Manjo and environs, Cameroon
Ngambu Aloysius Afahnwie, Victor Fonabe Embui, Lemnyuy Prosper Yiika, Kouankap Nono Gus Djibril, Fomekong Bertrand Kehding
Abstract
This study seeks to evaluate stream sediments for metal exploration, pollution and ecological implications using single and cumulative pollution indices in the light of recent discoveries. The concentration of metals in stream sediments of Manjo and environs was evaluated using inductively coupled Plasma-mass spectrometry. The sediment samples exhibit high concentrations for Fe, Pb, Hg, Ga, Zn, Cr, Cu, Co, Ni, V, Sn, Ce, La, U and Th when compared with the geochemical threshold values of upper continental crust (UCC), indicating some strong anomalies for potential base metal mineralization and exploration implications. The single and cumulative pollution indices suggest sediment contamination severity and metallic pollution. Potential ecological risk index (RI: 17.682–457.791) and toxic risk index (TRI: 2.243–29.981) indicate high ecological and significant toxicity risks, suggesting biological effects of metals to sediment-dwelling organisms. Sediment quality guidelines suggest high toxicological impacts and response stress of metals (Pb, Cu, Cr and Ni) to the aquatic ecosystem flora and fauna. Natural versus anthropogenic input origins are ressponsible for sediments enrichment in base metals and metallic pollution in the study area. The sediments are sourced from mafic and quartzose sedimentary provenances and mainly deposited in a non-marine environment. In addition, the sediments are mature and display moderate to intense weathering and rich mostly in quartz. According to this research, there should be more focus on monitoring the point sources of metals entering aquatic environment from human-induced activities to abate the anthropogenic inputs. Commitment to research and the implementation of science-based strategies will be crucial in ensuring the ecological sustainability of the water sediments’ environment. More so, note is taken of the natural lithological contributions to the sediment geochemistry having implications for future mineral exploration ventures.