Determination of the Selected Heavy Metal Content and Its Associated Health Risks in Selected Vegetables Marketed in Bahir Dar Town, Northwest Ethiopia

Abstract

Introduction. Fresh vegetables are of a great value and the most common foods in the human diet around the world. They contain minerals, vitamins, antioxidants, antimetabolites, protein, carbohydrates, and water. However, they are a major source of heavy metals, which contain both essential and toxic heavy metals over a wide range of concentrations. The study sites serve as a regional commercial center, where vegetables such as cabbages, onions, carrots, potatoes, beetroots, lettuce, and tomatoes were irrigated year round and sold to consumers. The aim of the study was to determine the level of cadmium, chromium, copper, and lead and to estimate the health risks associated with their daily intake of vegetables marketed in Bahir Dar town, Northwest Ethiopia. Methods. The concentrations of copper (Cu), chromium (Cr), cadmium (Cd), and lead (Pb) were determined, and their health risks were estimated using estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TCR) for selected heavy metals by using flame atomic absorption spectrometry. A total of 5 kg composite samples for each type of vegetable were collected by simple random sampling from an open market in Bahir Dar town, Northwest Ethiopia, and subsamples (1.25 kg) were digested via the wet digestion method. Results. The average concentrations of Cr and Cu in all selected vegetables were lower than the maximum limit of expected values. However, the concentration (mg.kg−1) of Pb in carrots, potatoes, and beetroots exceeded the safe limit of 0.3 mg·kg−1 set by the FAO/WHO and the concentration of Cd (mg·kg−1) in carrots, which is higher than the FAO/WHO limit, 0.2 mg·kg−1, in dry weight. The health index (HI) values (mg·kg−1 day−1) of all vegetables except carrots were lower than one. The TCR values for Pb, Cd, and Cr in all vegetables exceeded the US-EPA recommended threshold risk limit, but the TCR value of carrot was above the moderate risk limit (>1 × 10−3) set by the US-EPA. Conclusion. This study indicated that the concentration level of lead and cadmium in potatoes, onions, carrots, and beetroots marketed in Bahir Dar town is not safe for use by the local community. The consumption of carrots in the study area may cause both noncancerous and cancerous health risks. Therefore, regular monitoring of these toxic metals in vegetables should be carried out to prevent heavy metal toxicity associated with the consumption of those vegetables marketed in Bahir Dar town, Ethiopia.