Heavy metal concentration in vegetables and their potential risk for human health

This study assesses heavy metal levels in the water, soil, and vegetables (swiss chard, lettuce, cabbage, collard green, tomato, green pepper, and carrot) irrigated with wastewater in Gamo, Ethiopia. The samples of soils, waters, and vegetables were randomly collected, processed, and analyzed for heavy metals using atomic absorption spectroscopy. The obtained results show that the mean concentrations of Cd, Cr, and Ni were the highest, and Pb, Zn, and Cu had the lowest concentration in irrigation waters. The levels of Cd in the Kulfo river area and Chamo Lake area and Cu in most of the farm soils were also found to be higher than the reference values. The study also revealed that the mean levels of Cd in most vegetables and Cr and Pb in some vegetables were higher than the maximum recommended limits set by the World Health Organization / Food and Agriculture Organization 2001. Among the vegetables, cabbage had the highest heavy metal content followed by Swiss-chard, carrot, tomato, collard green, green pepper, and lettuce. The hazard quotient obtained for Cu, and Ni in all vegetable samples and Cd in some vegetable samples exceeded 1. It indicates that there are potential health risks to consumers. This study recommends regular monitoring over heavy metals contents in soils, waters, and foodstuffs to prevent their excessive accumulation in food chains.