International Journal of Phytoremediation, 9:1–13, 2007 Copyright C  Taylor & Francis Group, LLC ISSN: 1522-6514 print / 1549-7879 online DOI: 10.1080/15226510601139359 CAPABILITY OF SELECTED CROP PLANTS FOR SHOOT MERCURY ACCUMULATION FROM POLLUTED SOILS: PHYTOREMEDIATION PERSPECTIVES Luis Rodriguez, Jesusa Rinc´ on, Isaac Asencio, and Laura Rodr´ ıguez-Castellanos Department of Chemical Engineering, Faculty of Environmental Sciences, University of Castilla-La Mancha, Toledo, Spain High-biomass crops can be considered as an alternative to hyperaccumulator plants to phytoremediate soils contaminated by heavy metals. In order to assess their practical capability for the absorption and accumulation of Hg in shoots, barley, white lupine, lentil, and chickpea were tested in pot experiments using several growth substrates. In the first experimental series, plants were grown in a mixture of vermiculite and perlite spiked with 8.35 μgg –1 d.w. of soluble Hg. The mercury concentration of the plants’ aerial tissues ranged from 1.51 to 5.13 μgg –1 d.w. with lentil and lupine showing the highest values. In a second experiment carried out using a Hg-polluted soil (32.16 μgg –1 d.w.) collected from a historical mining area (Almad´ en, Spain), the crop plants tested only reached shoot Hg concentration up to 1.13 μgg –1 d.w. In the third experimental series, the Almad´ en soil was spiked with 1 μgg –1 d.w. of soluble Hg; as a result, mercury concentrations in the plant shoots increased approximately 6 times for lupine, 5 times for chickpea, and 3.5 times for barley and lentil, with respect to those obtained with the original soil without Hg added. This marked difference was attributed to the low availability of Hg in the original Almad´ en soil and its subsequent increase in the Hg-spiked soil. The low mercury accumulation yields obtained for all plants do not make a successful decontamination of the Almad´ en soils possible by phytoremediation using crop plants. However, since the crops tested can effectively decrease the plant-available Hg level in this soil, their use could, to some extent, reduce the environmental risk of Hg pollution in the area. KEY WORDS: mercury availability, barley, lupine, chickpea, lentil, phytoextraction INTRODUCTION The contamination of soils by heavy metals has become one of the most important environmental problems in developed and developing countries. Mining operations, metal smelting, electroplating, gas exhausts, energy and fuel production, downwash from power lines, intensive agriculture, and sludge dumping are some of the numerous human activities that contaminate soils with large quantities of toxic metals (Kumar et al., 1995). Address correspondence to Luis Rodriguez, Departamento de Ingenier´ ıa Qu´ ımica, Facultad de Ciencias del Medio Ambiente, Universidad de Castilla-La Mancha, Avda. Carlos III, s/n, 45071, Toledo, Spain. E-mail: Luis.RRomero@uclm.es 1