Plantas hiperacomuladoras y tolerantes a metales pesados

Asian J. Exp. Sci., Vol. 23, No. 1, 2009; 1-6

Tolerant and Hyperaccumulators Autochthonous Plant Species from Mine Tailing Disposal Sites
M.A. Salas-Luévano1*, E. Manzanares-Acuña2, C. Letechipía-de León2 and H.R. Vega-Carrillo2
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Unidad Académica de Agronomía Universidad Autónoma de Zacatecas Apdo. Postal 336, 98000 Zacatecas, Zac. México Unidad Académica de Estudios NuclearesUniversidad Autónoma de Zacatecas C. Ciprés 10, Fracc. La Peñuela, 98068 Zacatecas, Zac. México

Abstract : Mining activity in Zacatecas Mexico has generated huge areas affected by heavy metals contamination, especially lead. The phytoremediation is a user friendly technology for the cleanup of contaminated environments. A crucial aspect for the practical use of this technique is the selection ofadequate native plant species with high tolerance and capacity to accumulate the metals. The aim of this study was to identify autochthonous plant species that have potential capability for remediation of soil contaminated with lead. Seventeen different families of endemic plant species were identified in a polluted area showing large differences in the shoot’s lead accumulation. The highest shoot Pbconcentrations were found in Amaranthus hybridus (2208 µg/g) however the lead bioconcentration factor for this plant is less than 1. Only for Buddleja scordioides (Buddlejaceae) and Cerdia congestiflora (Caryophilaceae) the Pb bioconcentration factors are 1.31 and 1.05, respectively, which classifies them as lead-tolerant species. Key words : Phytoremediation, Lead, Zacatecas, Mine tailings.Introduction
After the discovery of the American continent the exploitation of mines reached a primitive industrial scale, with the consequent production of mine or mill tailings affecting adversely air, soil and water (Iskander et al., 1994). Mine tailings disposal sites from inactive or abandoned mine sites are worldwide prevalent in arid and semiarid regions. Major areas include northernMexico, western United States, pacific coast of South America, southwestern Spain, western India, South Africa and Australia. (Mendez et al., 2008). Tailings have elevated concentrations of metals such as arsenic, cadmium, copper,

manganese, iron and zinc. Is well known that, lead soil pollution causes a wide range of health and environmental problems (Kabata-Pendias and Pendias 1992). Deposition ofmetal-rich wastes in terrestrial environments by the metal mining industry has generated new habitats for potential microevolution and colonization of metal adapted variants of common species and for metallophytes colonization (Baker, 1984; Bush and Barret, 1993; Ginocchio et al., 2002). Abandoned and naturally recolonized old mine sites can therefore be seen not only as a liability but also aresource base of unique genetic materials of plant species suitable for phytostabilization and phytoremediation. The

* Corresponding author : Miguel A. Salas-Luévano; E-mail: masalas@uaz.edu.mx, Phone/Fax: +(52)492 9244147

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Salas-Luévano M.A. et al. (2009) Asian J. Exp. Sci., 23(1), 1-6

study of these plants and their colonization behavior and evolution observable on former mine siteshas improved closure and rehabilitation strategies in some mined areas of developed countries. (Gunn, 1995) Interest in phytoremediation has grown significantly following the identification of metal hyperaccumulator plant species. Nowadays, approximately 400 plant species from at least 45 plant families have been reported to hyperaccumulate metals (Baker et al., 1999; Reves and Baker, 2000). Theprimary motivation behind the development of phytoremediative technologies is the potential for low-cost remediation (Ensley, 2000). Comparing this technology to available physical and chemical methods of soil remediation, the use of plants is less disruptive to the environment (Cunningham and Berti, 2000). The plant species named hyperaccumulators may accumulate up to 100 times more metals than...