Efects of acid mine drainage on groundwater quality: legal and technical aspects

Abstract

Mining activities can increase environmental problems, compromising soils, surface water, groundwater, atmosphere and biota. Mineral exploitation can result in the exposure of large amounts of sulfides to weathering processes that generate acid effluents due to the formation of acid mine drainage (AMD), promoting solubilisation and transporting of metals to natural waters. However, the hydrochemical variations of groundwater in mining areas and the effects of AMD on aquifers were still poorly investigated. This work aimed to identify the main legal aspects for managing the quality of water resources in Brazil, specifically the groundwaters, in order to integrate environmental, technical and legal aspects concerning the impacts of AMD on groundwaters, thus allowing us to identify the factors to be developed in order to effectively protect these resources. The definition of criteria for the release of acid effluents into soils and water resources is essential to project a system for the collection, treatment and final disposal of wastes in mining areas complying with basic parameters of environmental quality. Therefore, a careful evaluation of environmental and geochemical processes is essential during the pre-mining, mining and post-operation planning. Thus, the problems related to the acid effluents, which compromises the ecosystems in deep dimensions, will not be solved in short time through punctual intervention disjointed with legal and environmental aspects.