An evaluation of the efficiency of cultural plants to remove heavy metals from growing mediu

Contamination of heavy metals in the environment is one of major concern because of their toxicity and threat to human life and the environment. Phytoextraction, using plants to extract heavy metals from contaminated soils is an emerging technology. In this work, in order to find a suitable plant species for use in cleaning up the soil in an industrial region, some crop species, which are cultivated by farmers on these soils, were studied. The effects of various concentrations of four heavy metals including Cd, Cr, Co and Ni were studied in two cultivars of wheat (Triticum aestivum L.), bean (Phaseolus vulgaris L.) and alfalfa (Medicago sativa L.) in hydroponic culture media under controlled environmental conditions. The results showed that, despite a higher tissue concentration, and because of a low biomass particularly under toxicity conditions, alfalfa was not an effective species in removing heavy metals from the medium. In contrast, regarding the biomass, metal content, as well as % recovery values, it became apparent that the bean plant was the most effective crop in removing heavy metals from medium.