Phytoremediation efficiency of crop plants in removing cadmium, lead and zinc from soil

The experiment was carried out in 1999-2001 at the University of Agriculture in Krakow (Poland) to study the capacity of nine crops (red beet, field pumpkin, chicory, bean, barley, white cabbage, maize, alfalfa, and parsnip) to remove cadmium (Cd), lead (Pb) and zinc (Zn) from different soil horizons (0-20, 20-40, 40-60 cm). The content of exchangeable Cd, Pb, and Zn decreased along with the depth in the soil profile. Red beet cultivation reduced the exchangeable Cd content in the soil by 10.3% and by 8.6% in field pumpkin, barley and maize cultivation in the 0-20 cm horizon. White cabbage and maize decreased Cd in the 20-40 cm horizon by 40.0 and 28.8%, respectively. White cabbage was found to be the most effective in removing Pb from the soil profile. Common bean, maize, and alfalfa reduced exchangeable Pb in two upper horizons of the soil: 0-20 and 20-40 cm. After field pumpkin cultivation, the decrease in Pb contamination in the 0-20 cm horizon was 7.4%. White cabbage and chicory reduced exchangeable Zn content in the surface horizon by 21.5 and 14.1%, respectively. According to their efficiency in metal reduction, maize and red beet may be indicated as potential removers of Cd, cabbage and field pumpkin, of Pb, and cabbage, of Zn.