POTENTIAL TREE SPECIES FOR REVEGETATION OF SALINE TAILING CONTAMINATED WITH ARSENIC

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. O beneficiamento dos minérios de ouro explotados em Paracatu, MG, gera rejeitos com características químicas e físicas limitantes ao crescimento de plantas, principalmente pelo elevado teor de arsênio (As) e salinidade. Para a revegetação desse material, é necessário identificar espécies capazes de se desenvolver sob essas condições. O objetivo deste trabalho foi avaliar o potencial de quatro espécies arbóreas para a revegetação de rejeito salino contaminado com As. O substrato de plantio consistiu em rejeitos provenientes do beneficiamento do minério B1. As espécies Tibouchina granulosa (quaresmeira), Schizolobium amazonicum Huber ex Ducke (paricá), Euterpe edulis Mart. (juçara) e Cassia grandis (cássia-rósea) foram plantadas por meio de mudas e, após quatro meses de cultivo, foram avaliados atributos dos substratos e das plantas. Diversas plantas apresentaram sintomas causados, possivelmente, pela toxicidade de As. Esses sintomas foram mais evidentes e intensos nas plantas de quaresme