Monitoring of metallic micronutrients and heavy metals in herbs, spices and medicinal plants from Austria

Medicinal, aromatic and spice plants grown in different regions of Austria were monitored as to their Cd, Cu, Fe, Mn, Pb and Zn contents. Since the plants were grown under common field conditions, the essential elements were within the usual ranges for plant material. The contamination level with the toxic heavy metals, Pb and Cd, can be classified as normally low. Most samples contained less than 0.2 mg kg(-1) Cd and less than 1.5 mg kg(-1) Pb on a dry weight basis. Comparison with previous investigations suggests that contaminations with Pb occur rather by chance, whereas enhanced Cd values are restricted to some species having a tendency to accumulate this heavy metal. Some such species are St. John's wort, poppy, yarrow, chamomile and absinth. Careful choice of growing site and appropriate soil management can reduce the Cd uptake of these critical species. These precautions are important when larger amounts of the product are consumed.