Background: Vegetables grown at contaminated sites can take up and accumulate toxic and potentially toxic elements at concentrations that are toxic to human health. The present study determined the levels of potentially toxic elements/PTEs in irrigation water, soil and vegetable samples grown along contaminated river and assessed the potential health risks to consumers. Results: The average concentrations of Mn, Sr and Cr in the irrigation water were higher than the international guideline values. The levels of As, Cr, B and Ni in most of the farm soils were also found to be higher than the guideline values. Other PTEs, although not exceeding the recommended limits were relatively high in the soil and water samples. The study also revealed that the mean levels of Cr, Cd and Fe in most vegetables were higher than the maximum recommended limits. Swiss chard was maximally contaminated with PTEs followed by lettuce, cabbage, Ethiopian kale, carrot and potato. Hence, frequent consumption of lettuce and Swiss chard may cause serious health risks to consumers. Conclusion: The levels of many elements were varied with location, suggesting localized inputs of the various contaminants related to industrial and other activities that generate wastewater.

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The Akaki River and its tributaries, in the city of Addis Ababa, are polluted by potentially toxic elements (PTEs) (Sb, Zn, Cd, As, Hg, Cu, Pb, Fe, V, Ni, Co, Mn, Cr, B, Sr and Ba) in varying degrees due to the significantly fast urban expansion and the industrial activities. The water samples collected from twenty-six different locations or sampling sites along the River and some of its tributaries were analyzed by ICP-MS to determine PTEs. The multivariate component analysis was used to evaluate the relationship and interdependency among the PTEs. The results showed that the mean concentrations for most of PTEs exceeded the recommended limits of drinking and irrigation water quality guidelines. A strong and positive relationship was observed among many of PTEs in the river water indicating common sources. The concentrations of many PTEs in the study area exceeded those previously reported and also varied with site or location, signifying localized contributions of the different contaminants associated with municipal, domestic, industrial, hospitals, garages and other activities. These findings of this study should help highlight and focus water quality management on key PTEs of concern and prioritize efforts to mitigate their release into surface waters in the city. Given the potential health implications of the PTEs mitigation measures should be sought as a matter of urgency by the relevant authorities in Ethiopia.