Influência de fatores naturais e antropogênicos na qualidade ambiental da Baía de Sepetiba - RJ

Abstract

This work aims to investigate Sepetiba Bay's paleoenvironmental evolution using three drill cores, namely SP4, SP9, and SP11. Located in Rio de Janeiro (SE, Brazil), Sepetiba Bay is a coastal body suffering significantly from recent human-induced eutrophication. A multiproxy approach was carried out in the three cores, where from textural, mineralogy, geochemical, and micropaleontological data, it was possible to elucidate the processes of sediment transport and changes in the environment over the years. SP4 was the testimony considered the most worrying, with high levels of pollution, it was the testimony that showed how much the environmental disaster sponsored by Cia Ingá Mercantil was harmful to the maintenance of life in Sepetiba Bay, leaving the testimony highly enriched with PTEs such as Cd and Zn. SP9, more distal and closer to the Marambaia sandbank, explained that even in regions far from the source area, the environment still suffers from significant impacts of pollution. In addition, the bottom material dredging process, combined with the action of the Marambaia Barrier Island as a reducer of the local hydrodynamics, led to a more significant accumulation of pollutants in the region. Finally, core SP11, the most external of all and the one with the oldest record (~2250 BP), and a continuous succession of foraminifera, also identified a significant amount of PTEs (Zn and Cd), but not as tall as the other testimonies. The faunal succession of SP11 was divided into 4 phases according to changes in the assembly. A significant increase in the genus Ammonia was noted in the last interval, in addition to the identification of an invasive species in the region, typical of the Caribbean Sea, called Ammonia buzasi , which can be a great indication of the disturbance of man in the environment, even if more oceanic.