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Abstract

The present work is a study and research about gold mining as a main destruction activity in the district of Poconé northem border of the Pantanal in the state of Mato-Grosso. The inadequate way of using mercury during the process of treatment to obtain gold is worring. The study of the fauna and flora of Poconé is a way of contributing to the process of evaluation of this activity of the Pantganal. In the present work, two species of Molluscs Bivalves were selected, Castalia ambigua and Anodontites trapesialis in order to determine the total amount of mercury used during the process of mining, and its use in bioassays in the laboratory. This result was obtained in a Spectrophotometer of Atomic Fluorescence with a grade of sensibility measure in subnanogrames. Determinations made with the Castalia ambigua at the Corrego Piranema (0.64 ± 0.70 µgHg.g-1) and the Bento Gomes River (0.37 ± 0.0.35 µgHg.g-1) of which the waters drain the mining areas, showed concentrations of mercury in a total amount above that permitted by the WHO (1991). The organisms that function as filters can be used more efficiently to indicate the presence of mercury in the process of analysis, it was clear that the series which compound the floating organisms are important factor in the process incorporation of the mercury. Organisms which were submitted to a process of treatment where just Hg0 was used, presented decreasing values in a amount of 1.32 to 1.86 µgHg.g-1. This result shows that the transportation and the process of incorporation of bioincreasing of this metal are directly related to the material formed by the suspension material transported by the water of the rivers.