Variability of selected heavy metals in surface sediments and ecological risks in the Solwezi and Kifubwa Rivers, Northwestern province, Zambia

Understanding the variability of heavy metals in surface sediments and how they accumulate is important not only in ecology and biodiversity conservation but also in aquatic natural resources management. This study investigated the level of some heavy metal contaminants in the Kifubwa and Solwezi Rivers in the Northwestern Province of Zambia. We used an atomic absorption spectrophotometer (AAS) to determine the levels of heavy metals in the surface sediments. Six sites known to be associated with heavy metal anthropogenic activities were sampled. In these sites, six elements, namely Cu, Co, Fe, Mn, Pb, and Zn, were targeted and measured in surface sediments from these two rivers. The mean values of these elements in each river were determined. To understand the ecological risk related to heavy metal contamination, we calculated the contamination factor (CF), the contamination degree (CD), as well as the pollution load index (PLI) for each element at each site in each river. These indices showed little contamination in the surface sediments of these rivers. This, therefore, implies that there are few ecological risks posed by heavy metal pollution to the ecosystems of the Solwezi and Kifubwa Rivers from sediments. However, follow-up studies should be carried out to monitor the levels of heavy metals in the fauna and flora of these rivers. Additionally, a follow-up study for the determination of other heavy metals such as arsenic, mercury, cadmium, and nickel must be conducted.