Monitoring and evaluation of potentially toxic metals and water conditions in designated rivers near industrial areas in Kano State, Nigeria

The aim of this study was to investigate the levels of potentially toxic metals and water conditions in designated rivers near high industrial activities in Kano State, Nigeria. A hundred and eight (108) surface water samples were evaluated from Rivers Sharada (S2), Salanta (S1), Tatsawarki (T), and Challawa (C) in Kano State, Nigeria, and analyzed for lead, chromium, cadmium, and zinc using atomic absorption spectrophotometry (AAS). The physicochemical, heavy metal parameters, including various water quality indices and health risk assessment models, were carried out to provide a comprehensive analysis. Temperature, pH, electrical conductivity, total dissolved solids, suspended solids, and dissolved oxygen ranged from 26–30 °C, 5.10–11.87, 0.08–11.00 µS/cm, 67.00–7050 mg/L, 5.00–80.00 mg/L, and 0.70–10.00 mg/L, respectively. The average mean concentrations of the potentially toxic metals were 2.15 mg/L, 2.09 mg/L, 0.90 mg/L, and 1.18 mg/L, for zinc (Zn), chromium (Cr), lead (Pb), and cadmium (Cd), respectively, with the detection of Pb limited to River Challawa. There was an insignificant correlation between the physico-chemical parameters and potentially toxic metal concentrations. Water quality indices, including the heavy metal pollution index (HPI) and heavy metal evaluation index (HEI), indicated poor water condition and high levels of potentially toxic metals. The hazard index (HI) value (HI > 1) indicated non-cancer-causing impacts, with children being more at risk than adults. It is recommended to advise farmers on clean sources of water for domestic use and crop irrigation.