Caracterização da qualidade ambiental em área de exploração mineral nas Minas do Camaquã em Caçapava do Sul – RS

Abstract

The mining industry is fundamental to society, supplying raw materials for the consumption and development of industrial and technological with imminent future expansions. However, mining activities have the potential to have severe adverse effects on the environment.This activity needs techniques for minimizing environmental impacts such as control measures, monitoring techniques and data survey. The aim of this study was to characterize the environmental quality of the area influenced by Copper mine in the region of Minas do Camaquã, at Caçapava do Sul, RS. The study area extends over about 8,955 hectares composed of sub-basins that contributes to Camaquã River, influenced by copper mining for more than a century. The study comprised stages of environmental and monitoring analysis. Environmental fragility was evaluated according to the empirical analysis of the fragility of natural and anthropic environments proposed by Ross (1994), using the geomorphology, pedology, climatology and land cover variables. The chemical analyzes of fluvial sediments were performed by EDXRF and the physical characterization followed by NBR 6502/95. For the permeability assays a Guelph permeameter was used. The geophysical surveys consisted in applying electroresistivity method and a dipole-dipole configuration was employed. The determination of the natural vulnerability of the aquifer to the contamination used the AVI method. The analysis of the environmental fragility maps permitted the observation, predominantly, of medium environmental fragility class. The sediments showed to be mostly sandy, for the chemical analyzes the highest concentrations were identified for Zn, Cu and Fe2O3 indicating a possible impact from the old copper mining. For soil permeability, the values found were compatible with the lithology. Geophysical results provided relevant information about hydrogeology. The results of the vulnerability of the aquifer indicate the possibility of contamination of the groundwater. Thus, this study contributed to the identification of the environmental reality of the region, historically impacted by mining. This information will help support environmental and territorial planning issues, aiming at the preservation of natural resources in line with the type of economic activity of the area.