PHYTOEXTRACTION OF COPPER AND NICKEL FROM SOILS CHARACTERIZED BY DIFFERENT DEGREES OF CHLORIDE SALINITY

Phytoremediation is a relatively modern technology that uses higher plants for the cleanup of polluted habitats. An example of this technology is phytoextraction, which uses metal-accumulating plants to remove toxic elements from contaminated soil. The effect of phytoextraction depends mostly upon the selection of a proper plant species, able to accumulate the desired element in specific environmental conditions. This is especially important in the case of saline soils. The aim of the present study was to determine the opportunity of using two plant genera (Zea mays L., Heliantus annus L.) to extract copper and nickel from the soils of different salinity. For this purpose, an investigation into the plants' growth and development traits, as well as a determination of the quantitative distribution of Ni and Cu in the parts of corn were carried out. It was established that the ability of plants to extract metals depended on the salt content in soil. At moderate soil salinity (0.3% NaCl), it increased up to 13% for copper and 20% for nickel in comparison with non-saline soil. Metal concentrations in tissues of Zea mays after 14-day cultivation in saline (0.3% NaCl) and non-saline soils with different concentrations of metals (50-2000 mg kg(-1)) were studied. The increasing NaCl concentration promoted a higher rate of metal transfer from roots to aerial parts and metal phytoextraction process. At the co-occurrence of the metals in soil, copper was more preferable by Zea mays than nickel. It was proven in the field experiments that during the whole growing period of Zea mays most of the metals accumulated in roots and stems, but not in ears, which allows us to use corn ears for food purposes.