Heavy metals concentration in selected vegetables grown in Dohuk City, Kurdistan region, Iraq

摘要

This research is conducted to evaluate the levels of some heavy metals (such as lead, cadmium, nickel, and copper) and their concentrations in water and in the most common vegetables (chard, celery, leek, onion and radish) which are cultivated in five common locations in Dohuk city farms, and irrigated with wastewater. The study in the concentration of heavy metals found in water used for vegetable irrigation indicates that the water of the College of Agriculture is not contaminated; while the water from all the other locations was highly contaminated. The results from the vegetable content analysis of heavy metals indicate that chard plants accumulate more lead and cadmium, while radish plants accumulate less. Concentrations of lead (Pb) and cadmium (Cd) obtained from vegetables grown in all the studied locations exceeds significantly in concentrations when obtained from the College of Agriculture location. Their relatively high concentration exceeds maximum permissible levels (MPL) in vegetables (WHO). The mean (Pb) concentrations of chard, celery, leek, onion, and radish plants were 4.188; 4.0; 3.719; 3.663; and 2.66 mg. kg~(-1) d. wt respectively, while the mean Cd concentration in chard, celery, leek, onion, and radish plants were 0.422, 0.37, 0.355, 0.346, and 0.228 mg. kg~(-1) d. wt respectively. Among locations, the Dilan Hall appeared to be more contaminated, whereas the College of Agriculture location is less contaminated. The concentration of both nickel (Ni) and copper (Cu) in all studied vegetables and in all locations didn't exceed (MPL) in vegetables. Mean Ni concentrations in chard, celery, leek, onion, and radish plants were 3.73; 4.07; 3.45; 3.66; and 3.25 mg. kg~(-1) d. wt, while Mean Cu concentrations were 14.4; 14.0; 12.8; 10.15; and 7.96 mg. kg~(-1) d. wt, respectively.