Monitoramento de elementos traço em amostras de sedimento das praias adjacentes à foz do Rio Doce

Abstract

The rupture of the mining tailings dam in Mariana -MG led to an environmental accident of unprecedented proportionsin Brazil. The arrival of the mud to the ocean through the Doce river caused even more concern regarding the extent of such damage, as the mud reached important beaches under environmental preservation, such as the beaches of Regencia and Comboios. The objective of this study was to quantify the trace elements Co, Cr, Cu, Mn, Ni, Pb and V in sand samples from beaches adjacent to the mouth of the Doce river, in order to verify the impacts caused to the region by the mud. Two sampling campaigns were carried out, one in the dry season and the other in the rainy season. The samples were decomposed with a microwave oven following the method US EPA 3051a. The analytes were determined by ICP-MS and the concentration levels (in µg.g-1) were 0.5 -4.08 for Co; 0.27 -23.44 for Cr; 0.33-2.2 for Cu; 15.45 -136.5 for Mn; 3.45 -8.19 for Ni; 0.99 -7.9 for Pb and 1.31 -21.2 for V. The results indicate that the analytes are below the values predicted by the Brazilian legislation, however, when compared to results of studies performed in other localities, some of the observed analytes are present in higher concentrations. The results also showed that the highest levels are in the region near the mouth of the Doce river, indicating that the region may be affected by particles thrown by the river in the ocean.