Cadmium, lead and nickel accumulation in chamomile plants grown on heavy metal-enriched soil

The effects of heavy metal (Pb, Ni, and Cd) enrichment of soil on growth and quality of chamomile plants as well as on the ability of plants to accumulate these metals in their tissues were investigated using pot experiments. Three parts of the plants were examined for heavy metal content: roots, leaves and flowers. The levels of heavy metals in the soil used in this study (1-30 mg kg(-1) for Cd, 60-1,800 mg kg(-1) for Ph and 20-600 mg kg(-1) for Ni) were not lethal for the chamomile plants. The heavy metal content in different tissues of these plants varied from very low concentrations to levels exceeding the maximum acceptable concentration limits according WHO. In general, the metal content in chamomile plant organs decreased in the following order: roots > leaves > flowers. Bioaccumulation factors which express the ratio of the metal concentration in the biological material to the metal concentration in soil or external solution were evaluated. It was found that the mobility within the chamomile plants decreased in the following order: Cd > Ni > Ph.