Capacidade da Lemna aequinoctialis para acumular metais pesados de água contaminada

Abstract

Plant ability for tolerating and accumulating high amount of heavy metal is used as a promissory technology for removing contaminants from highly polluted environments. The ability of the macrophyte L. aequinoctialis to remove heavy metal was studied in two different sampling times during its flowering. Samples of plant tissue L. aequinoctialis and water were collected for 800 hours at 48 hour intervals. Concentrations of Ni, Cu, Co, Cr, Mn, Zn, and Fe present in L. aequinoctialis and water were determined by flame atomic absorption spectrometry (FAAS). Data were subjected to the techniques of principal components analysis (PCA), hierarchical cluster analysis (HCA) and boxplot. We found that rhizofiltration of L. aequinoctialis removes high amount of heavy metal in this order: Cr >Ni>Cu> Fe > Zn >Mn. Only significant changes in chemical composition of the water, pH and electrical conductivity alter the absorption capacity of L. aequinoctialis.