Multivariate and health risks analysis of heavy metals in natural water sources around Enugu dumpsite, southeastern Nigeria

The concentrations of heavy metals and health risks associated with the consumption of domestic water sources around a dumpsite in Enugu (southeastern Nigeria) were assessed by atomic absorption spectrophotometry and multivariate analysis. The results showed the dumpsite leachate mean pH value of 4.1, Mn+ of 11.4 mu g/l, Fe3+ 4.1 mu g/l, Cd+ 0.3, As+ 6.03 mu g/l, Pb+ 2.47 mu g/l, Ni+ 14.13 mu g/l, and Cr3+ 1.48. The groundwater and surface water samples had mean heavy metal values as follows: Mn+ 5.23 and 0.75 mu g/l, Fe3+ 1.49 and 0.15 mu g/l, Cd+ 0.08 and 0.10 mu g/l, As+ 1.90 and 0.15 mu g/l, Pb+ 1.01 and 0.35 mu g/l, Ni+ 0.37 and 0.05 mu g/l, and Cr3+ 0.03 and 0.05 mu g/l, respectively. Comparison with maximum permissible limits indicated that the mean heavy metal concentrations of the tested samples were lower than the limits for drinking water, except for Mn+, As+, and Pb + , which were marginal above recommended limits. Principal component analysis results showed two principal components with the first principal component having high loadings of Mn+, Fe3+, As+, Pb+, Ni+, and Cr3+, which are statistically correlated. Probable sources of these contaminants include automobile parts and tools, batteries and electrical appliances and electronics heaped at the dumpsite. Analysis of variance results indicates a significant difference in datasets between and within each and both water sources. Human health risk assessment indices indicated that the water sources are moderate to highly polluted and could pose both non-carcinogenic and carcinogenic threats when consumed untreated, with children being more exposed than adults.

Automated summary

This study assessed the concentrations of heavy metals and associated health risks in domestic water sources around a dumpsite in Enugu, Nigeria. The results showed that the water sources were moderately to highly polluted and posed both non-carcinogenic and carcinogenic threats to human health, especially for children. The heavy metals, such as manganese, arsenic, and lead, were found to exceed recommended limits for drinking water.