Metais em sedimentos do estuário do Rio Doce (ES) após rompimento da barragem em Mariana (MG)

Abstract

Estuaries are coastal environments that hold many organisms and have sediments that can adsorb metals. These environments are susceptible to anthropic activities, such as the mud from the dam rupture of Fundão, operated by the Samarco mining company in Mariana (MG). Hence, this work was developed with the aim of verifying the presence of metals in sediments of the estuary after the rupture of the dam. For this purpose, sediments were collected from the estuary of the Doce river, located in the district of Linhares (ES), Brazil. The material was collect at 40 cm depth on a reference point and five more points and subjected to a sequential extraction for analysis of iron, manganese, copper, nickel, chromium, cobalt, lead and zinc concentrations. The exchangeable and soluble fractions, associated to carbonates, ferrihydrite, lepidocrocite, crystalline forms and pyrite, were determined by atomic absorption spectrometry. It was observed a high concentration of metals, mainly, iron, manganese, nickel and copper, exceeding permitted world levels that were proposed in the literature, considering the Threshold Effects Level (TEL) and the Probable Effect Level (PEL). The results shows that the surface layers (0-3 cm) were mainly composed of the mud material and also that the highest concentrations of the metals were in the fractions associated with iron oxides.