Assessment of Potentially Toxic Elements in Soils, Water and Vegetables Around River Salanta Area of Kano State, Nigeria: Health Risk Analysis

Anthropogenic activities have increased potentially toxic concentrations in our environments leading to rising health risk. This study was carried out in Salanta area of Kano State, Nigeria with the aim of exploring the impact of industries on the environment due to the release of potentially toxic element (PTE) in soils and water and its uptake by plants. These toxic elements [cadmium (Cd), chromium (Cr), lead (Pb) and zinc (Zn)] in soils, water and vegetables were analysed using atomic absorption spectrophotometry (AAS). The mean values of PTEs in 50 samples of soils and vegetables ranged from 0.50 to 7.50 mg/kg, 2.11 to 38.25 mg/kg, 0.001 to 3.13 mg/kg, 4.25 to 229.00 mg/kg and 0.25 to 10.50 mg/kg, 3.25 to 39.75 mg/kg, not detected (ND) to 0.023 mg/kg, 2.75 to 109.00 mg/kg for Cd, Cr, Pb and Zn, respectively, while in 18 surface water samples collected, it ranged from ND to 2.50 mg/L, ND to 3.50 mg/L and 0.50 to 10.50 mg/L for Cd, Cr and Zn, respectively, as Pb was not detected. Geo-accumulation index (Igeo) and transfer factor (TF) were determined. Geo (Igeo) values showed that soil (extremely contaminated, 10.6) and vegetables were contaminated with Cd but Cr, Pb and Zn levels were low (Igeo < 0). Transfer factors for onions and lettuce were above 1 for Cr and only lettuce was above 1 for Zn. The Target Hazard Quotient for vegetables sampled was above 1 for Cd. Target Hazard Quotient for water samples was also above 1 for Cd and Cr. Target Hazard Quotient values were higher in children than adults. Results show degrees of pollution as Cd and Cr concentrations were above the permissible limits.