Contamination of the Summer and Winter Vegetables by Heavy Metals in a Multi–Industry District of Bangladesh

Heavy metal (Cr, Cu, Zn, As, Cd, and Pb) contamination of the summer and winter vegetables were examined in a multi–industry district of Bangladesh. In this district, various kinds of industries discharged their wastewater into nearby irrigation canals, contaminating the vegetables that were cultivated by using the irrigation water with the heavy metals. Among the vegetables, the heavy metal concentrations were the highest in root vegetables, followed by leaf vegetables for both the summer and winter vegetables. Zn was the highest, while Cd was the lowest in concentrations throughout the vegetables. Every heavy metal concentration was lower in the summer than in the winter vegetables. The reason is probably that the concentrations of irrigation water and soil were diluted by rainfall during the rainy season when the summer vegetables were grown. The health risk index, which enables to assess the potential health risk due to the ingestion of vegetables, showed a high value in root and leaf vegetables, which indicated that the root and leaf vegetables grown in the district were found unsuitable for human ingestion.