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Understanding the Extent of Heavy Metal Pollution in Drinking Water Supplies from Umunya, Nigeria: An Indexical and Statistical Assessment

Abstract Heavy metals in drinking water, even in low concentrations, can be very injurious to humans. Groundwater, spring and stream waters for public consumption in Umunya district were analyzed to understand the extent of heavy metal (Fe, Zn, Mn, Pb, Cr, and Ni) pollution. Several indexical and statistical tools were integrated to achieve the research objectives. The utilized indexical tools for pollution assessment (e.g., pollution index, Nemerow’s integrated pollution index, geoaccumulation index, heavy metal evaluation index, heavy metal pollution index, and modified heavy metal pollution index) showed that at least 40% of the analyzed water samples were loaded with heavy metals. Similarly, the overall index of pollution and synthetic pollution index, which were used for drinking water quality evaluation, confirmed that at least 40% of the water supplies are unsuitable for human consumption. Moreover, similar results were obtained from an ecological risk assessment performed on the samples. Overall, Pb and Ni were the most predominant pollutants that greatly impacted the quality of the water resources for human consumption. The performance and interrelationships of the utilized models were also evaluated. Strong correlations were observed among the models. Furthermore, multivariate statistical tools, such as correlation analysis and factor analysis, were used for the pollution source apportionment. The results showed that anthropogenic inputs are more important factors that influence the heavy metal pollution in the waters. Therefore, efforts should be made to treat the polluted water supplies before human consumption and more awareness campaigns should be encouraged to protect the water resources from further deterioration in quality.