Avaliação química, ecotoxicológica e genotoxicológica de águas de cavas de mineração a céu aberto

Abstract

Artificial lakes formed in open pit mining areas are complex units and constitute emerging environmental liabilities arising from the mining industry. Although they are increasing in number in several parts of the world, they still form a recent and little studied environmental problem, especially regarding the quality and toxicity of its waters, which may represent worrying environmental risks. This study describes the results of the seasonal analysis of chemical, ecotoxicological and genotoxicological aspects of the waters of three disused gold mining pit lakes located in Mara Rosa, Goiás, Brazil. Samples were collected in profile in two different climatic seasons, winter and summer, and were chemically analyzed to determine their load of metals and anions. Ecotoxicological Tests and Comet Assays were also developed with fish of the Danio rerio species. The results indicated that the concentrations of the chemical species analyzed were predominantly increased in the surface-bottom direction and higher during the dry season. Lago Azul waters have been shown to be chemically more compromised as they are acidic and rich in potentially toxic analytes such as aluminum, cadmium, lead, copper, manganese, nickel, and zinc. No significant ecotoxicological alterations were identified for any of the analyzed samples, although, in genotoxicological terms, Lago Azul presented DNA damage from concentrations of 25% in the dry season and 50% in the wet season.