Measurement of levels of heavy metal contamination in vegetables grown and sold in selected areas in Lebanon

Abstract

Vegetables sold in the Lebanese markets are likely to adsorb and/or absorb toxic heavy metals from implantation till they reach the consumer. The samples were purchased randomly from four major areas in Lebanon, namely Beirut, Jounieh, Tripoli, and Koura. The levels of four selected toxic heavy metals; lead, cadmium, chromium, and arsenic were determined in a total of 181 vegetable samples of which 66 are leafy vegetables, 84 are over ground vegetables, and 31 are underground grown vegetables. Overall, the levels ranged from non-detectable to 3.0904 µg/g for Pb, 0.0137 to 3.6170 µg/g for Cd, non-detectable to 19.55 µg/g for Cr, and nondetectable to 0.0636 µg/g for As, where µg/g refers to the weight of the metal per gram of dry sample weight. In all samples, the leafy vegetables contained considerably higher levels for all metals as compared to overground or underground vegetables. Washing the samples thoroughly with water before analysis has decreased the concentrations of toxic metals, more significantly so, for As.