Health Risk Assessment of Heavy Metals in Vegetables in an Endemic Esophageal Cancer Region in Iran

Background: Nowadays, the heavy metals pollution is increasing and the accumulation of these metals in food has posed adverse effects on humans such as inducing various kinds of cancer and non-cancer diseases. The Northeast of Iran, especially Torkman Sahra, has the maximum number of patients with esophageal cancer. Objectives: We investigated the levels of four heavy metals (Zn, Cd, Pb, and Cu) in cucumber and tomato samples in Golestan province, an endemic esophageal cancer region. We evaluated the levels and potential health risks of heavy metals in vegetable samples of Northeastern Iran. Methods: The heavy metal content of the samples was determined by polarography methods. All sample preparation and digestion procedures were carried out according to the Standard Methods for the Examination of Water and Wastewater, 20th Edition. Results: The results showed that Cd and Pb concentrations in cucumber and tomato were estimated to be respectively 2.4 to 14.4 and 1.6 to 7 folds higher whereas Zn and Cu levels were lower than the maximum permissible limit for vegetables. The amounts of Pb intake through the consumption of these vegetables were determined more than the provisional tolerable daily intake. The total non-cancer and cancer risk results indicated that the investigated region was relatively unsuitable for growing the vegetables in the view of the risk of the elevated intakes of heavy metals adversely affecting food safety for consumers. Pb was the heavy metal posing non-cancer risks while Cd caused the greatest cancer risk. Conclusions: It was concluded that due to the toxic effects of cadmium and lead, we should be more serious to reduce pollution levels in this region.