Contamination and risk assessment of heavy metals in stream sediments of Bambui area, Southern Cameroon

Abstract

Abstract The Bambui area is located southwestern part of the Pan-African fold belt in Cameroon, and it is found at the foot of Bamenda Mountains, which is part of the Cameroon Volcanic Line (CVL). The study area is made up of various rocks types such as alkali basalt, trachyte, rhyolite and ignimbrite with a granitic basement of the Pan Africa Fold belt. The main objective of this work was to assess the contamination and risk pose by heavy metals in stream sediments of Bambui area, southern Cameroon. Heavy metal contents in the representative stream sediment samples collected were determined using inductively coupled plasma-mass spectrometer (ICP-MS). The elevated content of Co, Cr, Cu, Mn, Ni, Pb, Th, V, Zn, La, Fe and Ti could be attributed to the geology of the area and anthropogenic metal input sources. The evaluation of contamination factor, degree of contamination, modified degree of contamination, enrichment factor, ecological risk factor and potential ecological risk index revealed that the sediments have low to high ecological risk index. Pollution load index (0.78-1.60), geo-accumulation load index (1.73-5641.91) and anthropogenic metal input (0-5.25) indicate heavy metal contamination of the study area. Geogenic origins, agricultural practices, municipal waste disposal into streams, biosolids and animal manure were identified as the major sources of heavy metals in stream sediments of the study area.