Horizontal and vertical distribution of selected metals in the kubanni river,nigeria as determined by neutron activation analysis

Abstract

Neutron Activation Analysis (NAA) was used for the determination of metal concentrations of sediments sampled at specific locations of the Kubanni River in Nigeria. The sedimentation process was assessed by examining the variation of the concentrations of the metals in different cores with sediment depths. Fifteen metals: arsenic (As), cerium (Ce), europium (Eu), iron (Fe), gadolinium (Gd), hafnium (Hf), holmium (Ho), potassium (K), lanthanum (La), lutetium (Lu), samarium (Sm), scandium (Sc), thorium (Th), uranium (U), and ytterbium (Yb) were detected from the sediments in substantial concentrations; higher than the parts per million (μg g^‐1) value in some cases. Our results showed contamination of the surface sediments by U and Th, suggesting contributions from phosphate fertilizers used in farmlands around the basin as potential sources of these pollutants. Aeolian depositions emanating from the uranium‐rich region of Air (Niger) in the Saharan desert were considered to be other possibilities.