Metal concentrations, fluxes, inventories and chronologies in sediments from Sepetiba and Ribeira Bays: a comparative study.
Three sediment cores were sampled at Sepetiba Bay and four cores at Ribeira Bay, Rio de Janeiro State, Brazil. Sediment accumulation rates and chronologies were obtained from (210)Pb activity-depth profiles. Sediment accumulation rates in Ribera Bay ranged from 1.2 mm y(-1) in the inner bay to 2.6 mm y(-1) close to its entrance. In Sepetiba Bay two sediment accumulation rates were observed: a lower rate of 0.35 cm y(-1) before the 1960s and 0.76 cm y(-1) since then. The cause of this change is due to the construction of the Santa Cecília impoundment (1955) that brings water from the Paraíba do Sul Basin into the Guandu River, which increased its flow from the original 20 m(3)s(-1) to 160 m(3)s(-1). Concentration of 44 elements was obtained by ICP-MS after total dissolution of samples from two selected cores. The relative differences between the concentrations of crustal elements, such as Al, Fe and Ti are only about 20% (p<0.05). Cd and Zn are 15 and four times larger in Sepetiba Bay than in Ribeira Bay, respectively. Other major and minor elements show lower statistically significant differences. The enrichment factors and metal inventories show that Sepetiba Bay can be considered polluted with Bi, Cd, Cr, Cu, Sb and Zn. Particularly, Cd and Zn present concentrations three and four times higher than the Brazilian existing limits.
Programa de Engenharia Nuclear, COPPE/UFRJ, Cidade Universitária, Caixa Postal 68.509, 21945-970 Rio de Janeiro, Brazil.
Franciane
F
de Carvalho Gomes
José Marcus
JM
Godoy
Maria Luiza D P
ML
Godoy
Zenildo
Z
Lara de Carvalho
Ricardo
R
Tadeu Lopes
Joan Albert
JA
Sanchez-Cabeza
Luiz
L
Drude de Lacerda
Julio
J
Cesar Wasserman
D001938:Brazil; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D007856:Lead Radioisotopes / Q000032:analysis; D008670:Metals / Q000032:analysis*; D015203:Reproducibility of Results; D013997:Time Factors; D014874:Water Pollutants, Chemical
D007856:Lead Radioisotopes; D008670:Metals; D014874:Water Pollutants, Chemical