PRELIMINARY ASSESSMENT OF Cd, Cr, Ni, Pb AND Zn LEVELS IN MANGROVE SEDIMENTS OF SACO DO MAMANGUÁ (ILHA GRANDE BAY, RJ)

Saco do Mamanguá” is located in Ilha Grande Bay, west coast Rio de Janeiro State and suffers intense pressure degradation, mainly by speculation to build "resorts". The region is extremely vulnerable, given that there are in the region of Ilha Grande bay potentially polluting enterprises, such as mangroves. Samples of surface sediments were collected in “Saco do Mamanguá”. In this region, samples were collected at five sampling points parallel to the shoreline at a distance of approximately 10 m between them. Subsequently dried, sieved and analyzed for physico-chemical characterization and determination of heavy metals: Cd, Cr, Ni, Pb and Zn after digestion with aqua regia assisted by microwave radiation. The metal concentrations were determined by atomic absorption spectrometry with flame. The results showed that the sediments in “Saco do Mamanguá” mangrove presents average levels of Cd, Ni and Pb above the established as criteria for sediment quality by environmental agencies from Canadia and United States of America, demonstrating its vulnerability to contaminants of heavy metals existing in the Bay of Ilha Grande.