title: Geochronology of anthropogenic radionuclides in Ribeira Bay sediments, Rio de Janeiro, Brazil.
abstract: Ribeira Bay is located approximately 130 km south of the city of Rio de Janeiro and receives discharges of liquid effluent from the Angra dos Reis nuclear power plant (NPP) site, where two pressurized water reactors are located. To test whether the presence of anthropogenic radionuclides in sediments in Ribeira Bay could be correlated to the NPP operations, we sampled seven sediment cores and determined accumulation rates and chronologies. Only one sediment core did not exhibit a superficial mixing layer; this sample was used for dating purposes. Cesium-137 and (207)Bi were observed in this sediment profile, but their presence was associated with atmospheric fall-out rather than the nearby NPP. The exponential decay of (210)Pb concentration with sediment layer depth was verified below a superficial mixing layer for all other sediment cores. Calculated accumulation rates ranged from 1.2 mm y(-1) in the inner bay to 6.2 mm y(-1) close to its entrance.
authors.affiliation: Programa de Engenharia Nuclear, COPPE/UFRJ, Cidade Universitária, Caixa Postal 68.509, 21945-970 Rio de Janeiro, Brazil.
authors.forename: Franciane
authors.initials: F
authors.lastname: de Carvalho Gomes
authors.forename: José Marcus
authors.initials: JM
authors.lastname: Godoy
authors.forename: Maria Luiza D P
authors.initials: ML
authors.lastname: Godoy
authors.forename: Zenildo Lara
authors.initials: ZL
authors.lastname: de Carvalho
authors.forename: Ricardo Tadeu
authors.initials: RT
authors.lastname: Lopes
authors.forename: Joan-Albert
authors.initials: JA
authors.lastname: Sanchez-Cabeza
authors.forename: Iolanda
authors.initials: I
authors.lastname: Osvath
authors.forename: Luiz Drude
authors.initials: LD
authors.lastname: de Lacerda
mesh_terms: D001938:Brazil; D002588:Cesium Radioisotopes / Q000032:analysis; D002910:Chronology as Topic; D002947:Cities; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis* / Q000737:chemistry; D007856:Lead Radioisotopes / Q000032:analysis; D009792:Oceans and Seas; D011868:Radioisotopes / Q000032:analysis*; D055110:Radiometric Dating; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D007856:Lead Radioisotopes; D011868:Radioisotopes; D014874:Water Pollutants, Chemical