Fitorremediação de estéril de mina de cobre com mogno africano, utilizando resíduos orgânicos e amenizadores da fitotoxidez de metais.

Abstract

Copper mining (Cu) in the Brazilian Amazon brings concern about the residues production and the dispersion risk of the element, generating soil and water bodies pollution. The development of strategies such as phytoremediation, associated to the use of organic waste and mitigating metal/metalloid toxicity can be an important alternative for the establishment of plant species and the remediation of polluted areas. The objective was to evaluate the use of African mahogany (Khaya ivorensis A. Chev.) as a phytoremediation species and the addition of Brazil nut (CP) residues associated with metal/metalloid phytotoxicity enhancers in Cu. The treatments were: CP (control), plus silicon (Si), selenium (Se), biochar (Bio) and ashes from sugar cane boilers (Ci), Se + Si, Se + Ci and Se + Bio, totaling eight treatments. It was determined the Cu, Ni and Zn (higher levels in the sterile) concentrations in the substrates and plants after 90 days of mahogany cultivation. The accumulation (A), translocation factor (FT), bioconcentration factor (BCF) and biotransfer factor (FBT) parameters were calculated. The treatments with Se, Bio and Se + Ci provided higher levels of Cu in the plant, FBC and FBT, and lower FT. For Ni, FT was raised to 0.91 in the Si treatment. Ni FBC was the highest of the metals. The FT of Zn was higher than 1 in all treatments, except in Ci and Se, but with low levels of the element in the dry matter of the plants. African mahogany showed potential for phytostabilization of heavy metals in Cu mining residue, multi-contaminated. The contents of Cu in the vegetal tissue were characteristic of a hyperaccumulating species of the metal.