ASSESSMENT OF THE COMBINED TOXICITY OF HEAVY METALS IN FISH ASSOCIATED WITH THE ENVIRONMENTAL IMPACT CAUSED BY MINING ACTIVITIES
Keywords: behavior, cocktail effect, mixing of metals, zebrafish.
Mining activities are among the main sources of environmental contamination by heavy metals. In Brazil, the impacts caused by mining in the Rio Doce basin gained wide media coverage after the collapse of a tailings dam
of ore. In this environment, a mixture of heavy metals was observed, which can cause important changes in aquatic organisms such as fish. Against Furthermore, the objective of the present study was to identify and describe the impacts socio-environmental issues promoted by mining activities in the Rio Doce basin, as well as
such as investigating the effect of mixing heavy metals through changes behavioral and embryonic development of fish. For this, they were Two studies were conducted, in the first (Chapter 1) the chronological what is known about the environmental and social impacts caused by mining activities in the Rio Doce basin. In this study, impacts of mining on different levels of the ecosystem: from abiotic factors and molecular impacts to community impacts. While in the second study (Chapter 2) we used embryonic and behavioral markers of zebrafish (Danio rerio) to evaluate impacts caused by mixing metals. In this study, it was observed that the mixture of metals affects embryonic markers during early development (somitogenesis, hatching, and heartbeat), but not on markers of late development (length, locomotor behavior and thigmotaxis). Other an important finding is that in late markers the metals have an antagonistic effect on the mixture of metals, reducing the effects related to the individual exposure of metals. These results show that the mixture of heavy metals from mining in Rio Doce basin, may be affecting fish fitness in this environment