Abstract
Guanabara Bay, located in Rio de Janeiro state. It is surrounded by the second most important metropolitan area of the country. Over recent decades, land disturbance and urbanization in the surrounding area has significantly increased sediment input to the bay and had a negative effect on its overall environmental. This is especially related to high volumes of untreated sewage and industrial effluents. This study evaluates the history of this human impact through detailed examination of a sediment core taken from the northern portion of Guanabara Bay. A geochronology is established using ²¹⁰Pb dating and related to organic carbon and heavy metal fluxes to the sediments. This gave a calculated net average sedimentation rate for the core of 0.67 cm.year⁻¹. The organic carbon and heavy metals flux started to increase at the beginning of the last century and the highest values was observed in the top of the cores.
Highlights
Estuarine and coastal lagoon sediments provide unique records of the environmental history of a drainage basin, and frequently yield detailed evidence of the changes to catchment dynamics caused by human activities (Arnason and Fletcher 2003, Di Lauro et al 2004, Sanders et al 2006)
In order to address this gap in knowledge and to estimate the magnitude of heavy metal fluxes to the sediments of Guanabara Bay, the present study aims to assess the fluxes of key metals (Zn, Pb, Cu, Cr and Ni) into Guanabara Bay through an examination of their concentration in a dated sediment core using chemical and 210Pb analyses
Heavy metals are produced from a variety of natural and anthropogenic sources, for example, metal pollution can result from direct atmospheric deposition, geologic wea thering or through the discharge of agricultural, municipal, residential or industrial waste products (Demirak et al 2006)
Summary
Estuarine and coastal lagoon sediments provide unique records of the environmental history of a drainage basin, and frequently yield detailed evidence of the changes to catchment dynamics caused by human activities (Arnason and Fletcher 2003, Di Lauro et al 2004, Sanders et al 2006). The impacts of anthropogenic changes have greatly accelerated over the last 150 years and have been associated with important transformations in the aquatic environments linked to increased pollution loading resulting from rapid urbanization and the advent of radiometric dating methods, 210Pb (Marques Jr et al 2006) that have allowed the construction of geochronologies linked to the sedimentation Because of its relatively short half-life, 210Pb has been shown to be an ideal tracer for dating aquatic sediments deposited during the last 100 years, a period of time during which appreciable environmental changes have occurred due to urbanization and industrialization. The results will be used to evaluate the anthropogenic inputs of metals into the sediments of Guanabara Bay over time, the past 50 years of rapid economic development
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
