Pollution and Ecological Risk Assessment of Potentially Toxic Elements in Natural Waters from the Ameka Metallogenic District in Southeastern Nigeria

Abstract

In mining areas, several potentially toxic elements (PTEs) are often released in excess quantities into the ecosystem; thereby, predisposing both human beings and the environment to pollution risks. The current paper investigated the pollution status and ecological risks of PTEs in groundwater resources from Ameka and its environs, southeast Nigeria, using several numerical and chemometric models. Both hand-dug wells and borehole samples were analyzed. The order of abundance of the PTEs in the waters was Co > Se > Cd > Ni > Mn > Fe > Zn > As > Pb > Cu, for both hand-dug wells and borehole samples. Environmental pollution risk assessment models such as the contamination factor, contamination degree, pollution index, pollution load index, Nemerow integrated pollution index, and modified heavy metal pollution index showed that 100% of the samples were highly laden with PTEs. Similarly, the ecological risk assessment showed that 100% of the samples pose very high ecological risks. Furthermore, the water quality index and integrated water quality index jointly revealed that all the analyzed groundwater sources in this mining area were unsuitable for human consumption. Chemometric tools such as factor analysis and hierarchical cluster analysis were used to establish the inter-parameter relationships. It was realized that both geogenic and anthropogenic factors are responsible for the enrichment of the PTEs in the natural waters. Therefore, based on the overall findings of this study, adequate treatment of the polluted waters before drinking is highly recommended.