Salinity heavy metal interactions as evaluated by soil extraction and plant analysis

Both heavy metal pollution and saline water irrigation are increasing in the dry areas, especially in developing countries. The effects of soil and water salinity on the transfer of heavy metals to crops are, however, not well understood. The uptake of Zn, Cu and Cd from. polluted desert soil from the north west of Egypt was therefore evaluated in pot experiments with maize, irrigated either with NaCl or with NaCl + CaCl2 solutions. NaCl accelerated root mortality and increased both the concentration of heavy metals in soil saturation extract and their uptake by maize. In contrast to NaCl, CaCl2 affected solubility and plant uptake of heavy metals differently. While the solubility of heavy metals was enhanced by CaCl2, both root mortality and the uptake of heavy metals were depressed. It was concluded that salinity of irrigation water affects heavy metal uptake at least partly by modifying root functions.