GEOQUÍMICA DOS METAIS TRAÇO NOS SEDIMENTOS DOS CÂNIONS DO TALUDE CONTINENTAL DO ESTADO DE SERGIPE E ALAGOAS

Código

PAP046

Autores

José do Patrocínio Hora Alves, Carlos Alexandre Borges Garcia, Maria de Lara Palmeira de Macedo Arguelho, Maria Eulália Rocha Carneiro

Tema

QUALIDADE DA ÁGUA E SEDIMENTOS EM BACIAS HIDROGRÁFICAS E REGIÕES COSTEIRAS

Resumo

O In this work, the geochemical analysis was used to determine the origin and to identify the main factors which govern the distribution of trace metalsin the canyons sediments of the continental slope of Sergipe and south of Alagoas, Northeast of Brazil. The total concentrations presented the following variations: Al (3,92 ?4,47 %),Fe (2,95-3,54%), Ba (761,8?987,8?g.g-1), Cd (0,24 ?0,59?g.g-1), Co (6,31 ?9,47?g.g-1), Cr (33,59?56,30?g.g-1), Cu (12,59?15,98?g.g-1), Mn (300,2?572,7?g.g-1), Ni (21,92?28,43?g.g-1), Pb (33,59?56,30?g.g-1), V (61,71?74,29?g.g-1) e Zn (40,48?67,75?g.g-1).In general, a clear tendency of concentration variation with the depth was not observed. For most metals, no effect of seasonality was observed between the concentrations, except for Al and Mn, whose values were significantly different between dry and rainy periods. The superficial sediments of the Japaratuba canyon were significantly different from the surface sediments of the São Francisco canyonand showed distinct signatures for the trace elements. For the San Francisco canyon, the correlation matrix pointed to a continental origin for Ba, Co, Cu and Ni; an autochthonous process associated with the internal phytoplankton cycle for Cd, Cr and Pb, and an autigenic origin for Mn. While for the Japaratuba canyon an origin associated with detritus minerals, such as quartz and feldspar, was identified for Ba, Cu, Mn, Ni and Zn. It is also likely that some elements have been incorporated by physico-chemical processes and deposited along with the particulate material.