Espécies arbóreas potenciais para a revegetação de rejeito salino contaminado com arsênio

Abstract

The processing of gold ores exploited in Paracatu, MG, generates tailings with chemical and physical characteristics adverse to plants growth, mainly by high concentration of arsenic (As) and salinity. The revegetation of this material requeres identify species capable of grow under these conditions. This study aimed to evaluate the potential of four tree species for revegetation of saline tailing contaminated with As. The planting substrate consisted of tailings from processing of ore called B1. The species Tibouchina granulosa (quaresmeira), Schizolobium amazonicum Huber ex Ducke (paricá), Euterpe edulis Mart. (juçara) and Cassia grandis (cássia-rósea) were planted by seedlings and, after four months, the atributes of the substrate and plants were evaluated. Several plants showed symptoms possibly caused by As-toxicity. These symptoms were more evident and intense in quaresmeira and juçara. However, only the plants of quaresmeira died, probably due to the high rate of As-translocation (51 %) and absence of tolerance mechanisms of the specie. The potential use of species for revegetation of tailings follows the order paricá > cássia-rósea. Paricá is the one with the greatest potential for initial deployment of vegetation, demonstrating the greater ability to adapt to tailing characteristics. The juçara and quaresmeira species are not recommended for the revegetation of tailings. Probably arsenic and/or salinity affect the development of plants, being lethal to quaresmeira.