Heavy metal accumulation in plants grown in heavily polluted soils

In a polluted area, samples of soils and plants were collected and analyzed in order to assess the mobility and accumulation of Cd, Pb and Zn in plants as influenced by the of different metal forms in soil. Metals were accumulated in roots. Metal mobility in plants decreased in the order Zn>Cd>Pb; it was generally lower in heavily polluted areas. The content of all the three metals in plant roots correlated with topsoil concentration of their 2 mol/L HNO₃-extractable forms. Besides, Cd and Zn correlated with exchangeable and Zn also with the organic form content. The concentration factor as a measure of metal mobility from soil to plants decreased with increasing level of contamination. Presented at the 4th Mini-Symposium on Biosorption and Microbial Degradation, Prague, Czech Republic, November 26–29, 1996.