Response of kidney bean to concentration and chemical form of cadmium, zinc, and lead in polluted soils

Seven soils which had been polluted with heavy metals from a zinc smelter were sequentially extracted so that Cd, Zn, and Pb could be partitioned into five operationally defined geochemical fractions: exchangeable, carbonate, Fe-Mn oxide, organic, and residual fractions. Kidney beans were planted in the soils to examine the effect of concentration and chemical form of the metals in soil on the growth and metal uptake of the plants. The growth of kidney bean was restricted in heavy metal polluted soils compared with controls. Metal concentration and metal uptake by plants were correlated. The highest relationship was found between amount of metal uptake and the metal concentration in exchangeable + carbonate forms. The uptake of metals was according to their solubility sequence, i.e. Cd > Zn > Pb. The uptake rate of exchangeable + carbonate forms was the same for the three elements.