Geoquímica do sistema solo-água-planta em uma área impactada por rejeito da mineração de cobre

Abstract

The environmental impacts caused by mining activity are inevitable, which are associated with a large content of metallic elements disposed on the environment. The use of phytoremediation to ameliorate these areas has been used due to the low costs. Therefore, the use of species adapted the local climate and soils conditions are very important to the success of phytoremediation activities. The objectives of this study were: evaluate the copper dynamic along of soil profile and assess the risk of orchard irrigation with mine water; identify arboreal and shrub native species for copper bioaccumulation, and copper dynamic rhizosphere of native species. In an area contaminated with copper mining wastes, soil samples were collected along of soil profile and in the surface layer (0-20 cm); and at the rhizosphere of native species. Soil samples also were collected in banana orchard irrigated with water extracted of a copper mine. A floristic survey was performed to identify the plant species in the area, and leaves and roots of the species were sampled. For the assessment the contamination risk of food chain, soil samples of a site irrigated with mine water, and leaves, roots and fruits of banana tree, were collected. The soil samples were submitted the physical, chemical routine analysis, and copper fractionation. The plant tissue samples were submitted the acid digestion (HNO3‐HClO4). A sub-samples were submitted the mineralogical analyzes. High contents of copper were identified in study site, mostly associated with carbonates and organic matter. These high copper levels were mainly restricted the surface horizons, even with soil of coarser texture, thus indicating low mobilization along of soil profile. The use of mine water in banana crop favored the increase of copper in irrigated area and the increase in copper levels in banana fruits. The ratio between copper concentration in leaves and the copper bioavailable in soil (BCF) evidence that species are potentially phytostabilizers. The Bauhinia ugulata L shown potential to be used in recovery programs due the association with Cu with organic matter in rhizosphere.