Contents of Heavy Metals, Nitrates, and Nitrites in Cabbage

The contents of lead, cadmium, zinc, copper, iron, manganese, nitrites, and nitrates were determined in six species of cabbage of the cruciferous family obtained from different areas of Poland. The results were analyzed and compared in terms of the effect of local industrial (southern Poland, Katowice) or agricultural (southeastern Poland, Lublin) activities on the amounts of heavy metals in the tested vegetables. While the levels of cadmium, lead, and manganese correlated well with the different industrial levels of the locations, the concentrations of copper, iron, and zinc in the vegetables were not very different between the two cities. All the vegetables could generally be characterized by low levels of cadmium and lead (less than 0.1 mg·kg), and relatively high levels of zinc, iron, and manganese (3-10 mg·kg) regardless of location. Among the tested vegetables, Chinese cabbage (Brassica pekinensis Rupr) from Katowice consistently gave higher levels of all the analyzed elements (except zinc) than the same vegetable from Lublin, while the other specimens produced variable data. Red cabbage turned out to contain the highest levels of all contaminants compared to other vegetable species. Nitrate levels in all the Lublin samples were approximately equal, suggesting that the extensive fertilization in the Lublin area produces a uniform background level of these anions. On the other hand, the Katowice samples exhibited quite variable and extreme levels of nitrates and nitrites.