Potencial de espécies vegetais à fitorremediação de solo contaminado com cobre

Abstract

Mining is a worldwide activity of great importance due to the use of the metals that are extracted, like copper, in Brazil, with emphasis on the state of Pará. The objective of this research was to evaluate the potential, ie, ability, capacity of the species Schizolobium amazonicum, Leucaena leucocephala and Azadirachta indica submitted to soil contamination with copper mining tailings, to phytoremediate heavy metal. In order to reach the objective, bibliographical research and experiments were carried out, organized in three chapters. The first part is a literature review on mining, copper mining rejects , phytoremediation and the plants to be studied. The first chapter evaluates the potential of the species S. amazonicum, L. leucocephala and A. indica, submitted to the soil contaminated with copper waste through the production of dry phytomass, contents and distribution of copper in the root, cauline and foliar compartments of the species. The analyzed variables were the growth morphometric, the indices and translocation factors and the extraction coefficients. The phytoextraction coefficients were higher in the roots of the species studied. The second chapter had the objective of evaluating the effects caused by photosynthetic pigments and the activities of the superoxide dismutase and guaiacol peroxidase enzymes in the species S. amazonicum, L. leucocephala and A. indica, cultivated in substrate with copper concentration, and to evaluate possible changes in the chlorophyll content "a" and "b" and carotenoids. The analyzed variables were enzyme activity superoxide dismutase and guaiacol peroxidase, and the determination of photosynthetic pigments. The levels of chlorophyll a, b and carotenoids in the apical, intermediate and senescent compartments for the three species did not differ, but at the concentration of 400 mg dm-3, there was a change to A. indica. The third chapter was aimed at the chromosomal characterization through heterochromatic bands in the species S. amazonicum, L. leucocephala and A. indica, aiming to characterize cytogenetically, and to detect the appearance of possible chromosomal alterations coming from the contamination by copper in the substrate used in the cultivation of species. Through the plant material were made the chromosomal preparations, staining with fluorochromes, determination of the karyotype formula and analysis of the patterns of heterochromatic bands. For the species Schizolobium amazonicum the chromosomal number of 2n = 26 appears as new information for literature.