Assessing heavy metal content of a rural stream Southeast Nigeria for drinking and irrigation purposes

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The heavy metal concentrations of a rural stream in Southeast Nigeria were evaluated between November 2021 and October 2022 in 3 stations. Water Pollution Index (WPI) and non-carcinogenic health risk assessment were used to determine the water’s suitability for human consumption and irrigation. Eight heavy metals were evaluated using standard methods and compared with Nigerian Drinking Water Quality and Food and Agriculture Organization Irrigation Water Quality standards. The concentrations were; iron (0.34 – 3.78 mg/l), manganese (0.10 – 1.05 mg/l), copper (0.06 – 0.84 mg/l), zinc (0.22 – 1.87 mg/l), chromium (0.04 - 0.37 mg/l), lead (0.03 - 0.31 mg/l), cadmium (0.03 - 0.23 mg/l), and nickel (0.01 - 0.18 mg/l). Iron, manganese, chromium, lead, cadmium, and nickel exceeded acceptable limits. The WPI values – 5.02 – 6.57 (drinking) and 1.49 – 1.92 (irrigation) were greater than 1, indicating heavy pollution. The ingestion hazard indices (HI) 4.50 – 5.85 (adults) and 6.32 – 8.22 (children) were higher than the threshold value (1). Anthropogenic activities and seasons influenced the concentration of the metals, while chromium and cadmium were responsible for the observed adverse health risks. The burden of the health risk was more on the children. In conclusion, the Azueke stream’s water is unsuitable for human consumption and irrigation.