["Ex-situ" phytoextraction in soil contaminated by Pb]
2003
Rizzi, L. | Petruzzelli, G. | Pedron, F. | Barbafieri, M. | Pezzarossa, B. (Consiglio Nazionale delle Ricerche, Pisa (Italy). Istituto per lo Studio degli Ecosistemi)
The "ex-situ" phytoremediation potential has been assessed on a soil containing about 465 mg Pb kg*[-1) soil and 100 mg Zn kg*[-1). The experiments were conducted on a soil taken from a former MGP site and placed in boxes 1 x 1 m wide and 0.25 m high, equipped with a leaching collection system. Brassica juncea and Lupinus albus have been selected as possible species to extract heavy metals from the polluted soil. Due to the specific soil characteristics, a chelating agent (EDTA) was added to mobilize the metal not available for plants. EDTA was added at a concentration of 0.15 M. Plants were harvested at different times and separated into roots and shoots and Pb and Zn content was determined by AAS after HNO3 HClO4 mineralization. Results showed a good resistance of the selected plants to the chemical treatment and a noteworthy increase of Pb and Zn in shoots after EDTA addition. A second addition of the chelating agent induced a further accumulation of Pb in Brassica juncea. The phytoremediation of heavy metal contaminated soils is an emerging and a cost effective technology. The present study supports the potential of "ex-situ" phytoremediation to overcome some limitations of the technology, such as the depth of contamination and possible environmental problems, such as leaching linked to the use of chelating agents often necessary to mobilize heavy metals
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