Phytoremediation with corn (Zea mays L.) and Stevia compost on soils degraded by contamination with heavy metals

With the objective to reduce the heavy metals contamination of the soils in the center of the country, we decide to observe the effect of organic amendments (compost and vermicompost of Stevia). The present work was carried out using corn as a phytoremediating plant. The agricultural soils (Mantaro and Muqui of the Mantaro valley's localities) containing the greatest amounts of lead (Pb) and cadmium (Cd) and surpassing the Peruvian Environmental Quality Standards (SQE), were used. The Muqui soils contained the greatest amount of Pb and Cd, presenting negative effects such as a lower yield of leaves dry matter, stems and corn roots, in addition to a slower development. The corn absorbs the heavy metals from the soil as evidenced by the greater accumulation of lead and cadmium in the corn roots, thus confirming that the organic amendments contributes to solubilize the soil's Pb and Cd. However, the Stevia's vermicompost was more effective at absorbing the heavy metals from the soil. Calculations of bioconcentration Factor (BCF) and translocation (TF) indicate that corn is a plant exclusionary or stabilizing.