Evaluation of Potential Dietary Toxicity of Heavy Metals of Vegetables

Abstract

Introduction: Consumers are exposed to a diversity of chemicals in all areas of life. Air, water, soil and food are all unavoidable components of the human environment. Each of those elements influences the quality of human life, and each of them may be contaminated. Objective: Levels of cadmium (Cd), lead (Pb), mercury (Hg) and nickel (Ni) in vegetables and soils from Ohaji, Umuagwo and Owerri in southern Nigeria were determined and the potential health risks assessed. Methods: Commonly grown vegetables, fruits and food crops were collected from three different sites in southern Nigeria, washed, oven-dried in a hot air oven at 70–80°C for 24 h. Dried samples were powdered using pestle and mortar and sieved through muslin cloth. Samples (0.5 g each) were digested with perchloric acid and nitric acid (1:4) solution. The presence of lead, cadmium and nickel were analyzed in samples using the Unicam Atomic Absorption Spectrophotometer (AAS) Model 929. Results: Concentrations of Cd, Ni and Pb in Ohaji exceeded maximum allowable concentrations for agricultural soil. Cadmium, Ni, and Pb in vegetables were highest in Murraya koenigii, Piper guineense and Amaranthus viridis Linn, respectively. The estimated yearly intake of Pb, Cd and Ni in commonly consumed vegetables, Green leaf (Amaranthus viridis), fluted pumpkin (Telfaria occidetalis) and Curry leaf (Murraya koenigii) in Nigeria were calculated to be 1,210, 150 and 456 mg.kg-1, respectively. Conclusion: Taken together it might be concluded that these vegetables may contribute to the body burden of heavy metals especially lead.