Industrial Crops and Products 24 (2006) 230–237 Uptake of lead and zinc by wild plants growing on contaminated soils Mercedes Del R´ıo-Celestino a,∗ , Rafael Font b , Rafael Moreno-Rojas c , Antonio De Haro-Bail ´ on b a CIFA-ALAMEDA DEL OBISPO, I.F.A.P.A.-C.I.C.E. (Junta de Andaluc´ıa), Alameda del Obispo s/n, 14080 C ´ ordoba, Spain b Instituto de Agricultura Sostenible (CSIC), Apartado 4084, E-14080 C´ ordoba, Spain c Department of Bromatology, University of C´ ordoba, E-14071 C´ ordoba, Spain Abstract In studies performed in the Aznalc ´ ollar area (Southern Spain), several plant species have been identified as not only being able to grow on these polluted soils, but also to accumulate high amounts of the pollutants in their shoots. A pot experiment was conducted to investigate the phytoextraction efficiency of 11 plant species to extract and accumulate Pb and Zn gradually added to soil, and, therefore, to establish the suitability of these species for remediation of Pb and Zn polluted soils. The experiment was performed with the plants at a concentration of Pb of 500 mg Pb kg −1 , and a concentration of Zn of 130 mg Zn kg −1 , for 6 weeks of exposure. The mean shoot biomass production was not significantly different from the control for Pb and Zn treatments. It was found that the highest mean concentrations of Pb and Zn were accumulated in shoots of Amaranthus blitoides, Cynodon dactylon, Cichorium intybus and Sylibum marianum. For C. intybus, Pb concentrations in shoots were >1000 mg kg −1 , indicating hyperaccumulation for this element. The traslocation of Pb from roots to shoots was minimum in Chenopodium album, indicating significant metal inmobilisation by the roots, and, therefore, this species could be useful in phytostabilization of soils. When the biomass values were taken into account, C. dactylon, Hirsfeldia incana, Malva nicaeensis and Silybum marianum were more effective in removing Pb and/or Zn from the contaminated soil. © 2006 Elsevier B.V. All rights reserved. Keywords: Cichorium intybus; Cynodon dactylon; Hirsfeldia incana; Malva nicaeensis; Sylibum marianum; Heavy metals 1. Introduction Soils may become polluted with high concentrations of heavy metals both naturally, as a result of proximity to mineral outcrops or ore bodies, or anthropogenically, as a result of industrial activities. Metalliferous mining and processing, including the dumping of wastes, usually produces the most severe cases of heavy metal pollution (Wong, 2003; Freitas et al., 2004). ∗ Corresponding author. Tel.: +34 957499235; fax: +34 957499252. E-mail address: mdrc@cica.es (M. Del R´ıo-Celestino). Decontamination of soils polluted with heavy metals remains one of the most intractable problems of clean-up technology. Techniques in current use are based upon either extraction of metals physico-chemically, such as acid-leaching and electro-osmosis, or immobilization in situ, by e.g. vitrification (U.S. Army Toxic and Hazardous Materials Agency, 1987). All these methods require specialist equipment and operators. They are therefore costly and only appropriate for the decon- tamination of small areas of land where pressure of land use or development potential merits the outlay. Furthermore, they remove all biological activity from the treated medium and adversely affect its physical 0926-6690/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.indcrop.2006.06.013