LAUSR

The objective of this study is to develop a practical application for the remediation of heavy metal and organic contaminated soil using phytoremediation amended with electricity. The application of electricity near a growing plant may exert negative effects on the physicochemical characteristics of soil and, therefore, in the viability of the plants. This study evaluated the effect of the electricity on the pH and electric conductivity of soil. The aim of the study was to evaluate the response of the soil to the electricity to determine the optimum intensity of the electric field to improve the phytoremediation capacity of the plant, avoiding dramatic changes in the physicochemical properties of soil that may compromise the survival of plants. Three plant species were selected to test the influence of electricity in growing plants: Phalaris canariensis, Brassica rapa and Zea mays. The results suggested that a low-to-moderate voltage gradient (0.67–1 VDC/cm) could be used for the development of an electro-phytotechnology application with Brassica rapa for the treatment of a soil contaminated with metals and organics. The soil contained metal and organic contaminants: 50 mg/kg of Cd, 400 mg/kg of Cr, 500 mg/kg of Pb, 200 mg/kg of phenanthrene, and 100 mg/kg of anthracene. The phytoremediation tests with DC electricity were more effective in the phytoextraction of heavy metals from soil whereas the tests with AC electricity showed a special capacity in the degradation of polycyclic aromatic hydrocarbons. These results suggested that the combination of electricity with Brassica rapa could be an effective technology for the remediation of mixed contaminated soils.