CHEMICALLY ENHANCED PHYTOEXTRACTION OF RISK ELEMENTS FROM A CONTAMINATED AGRICULTURAL SOIL USING ZEA MAYS AND TRITICUM AESTIVUM: PERFORMANCE AND METAL MOBILIZATION OVER A THREE YEAR PERIOD

Enhanced phytoextraction using EDTA for the remediation of an agricultural soil contaminated with less mobile risk elements Cd and Pb originating from smelting activities in Pribram (Czech Republic) was assessed on the laboratory and the field scale. EDTA was applied to the first years crop Zea mays. Metal mobilization and metal uptake by the plants in the soil were monitored for two additional years when Triticum aestivum was planted. The application of EDTA effectively increased water-soluble Cd and Pb concentrations in the soil. These concentrations decreased over time. Anyhow, increased concentrations could be still observed in the third experimental year indicating a low possibility of groundwater pollution after the addition of EDTA during and also after the enhanced phytoextraction process under prevailing climatic conditions. EDTA-applications caused phytotoxicity and thereby decreased biomass production and increased Cd and Pb uptake by the plants. Phytoextraction efficiency and phytoextraction potential were too low for Cd and Pb phytoextraction in the field in a reasonable time frame (as less than one-tenth of a percent of total Cd and Pb could be removed). This strongly indicates that EDTA-enhanced phytoextraction as implemented in this study is not a suitable remediation technique for risk metal contaminated soils.