Avaliação da toxicidade de metais em daphnia magna

Abstract

The life quality modernization has led to the large scale use of various chemical products, some of these products are heavy metal compounds, and can cause intense environmental contamination, mainly in water. Metals are a non-natural degradation contaminant, which depending on the way they are found on the aquatic environment can be highly toxic, mainly for its cumulative effect one which can lead to death. This work had as its main goal, to establish the average effective initial concentration, CE(I)50, of the compounds: Cr, Cu and Cd. Using standard samples with different known concentrations, being the average standard concentration the one stablished on CONAMA 430/2011. The Eco toxicological trials with Daphnia magna were realized accordingly to the NBR 12.713(2009). The effective average concentration, CE(I)50,found for cadmium was 0.24 mg L -1, these being higher than the one allowed on the environment legislation (0.2 mg L-1). For the hexavalent chrome, the CE(I)50 that has been found was 1.15 mg L-1 , being much higher than the one allowed on the environmental legislation (0.1 mg L-1). The toxicity of Pb, Ni and Zn could not be determined due to these metals characteristics, which has made D. magna trials impossible. We have concluded that D. magna has a high sensibility to copper, high resistance to hexavalent chrome, and that the sensibility to cadmium is very close to the ones stablished on CONAMA 430 Resolution.