title: 137Cs in marine sediments of Admiralty Bay, King George Island, Antarctica.
abstract: The radionuclide cesium-137 ((137)Cs) is produced exclusively by anthropogenic processes and primarily by nuclear explosions. This study determined the reference inventory that is (137)Cs associated with the element's original input, and utilized the levels of activity of this radionuclide previously measured in five sediment profiles collected from Admiralty Bay, Antarctica, to investigate the mobility of this element in the environment. (137)Cs has a half-life of 30 years. Because of this, it is environmentally persistent and has been shown to accumulate in marine organisms. The mean reference inventory of this radionuclide in Admiralty Bay sediments, determined using high resolution gamma ray spectrometry, was 20.23±8.94 Bq m(-2), and within the ambient (137)Cs activity range. A model of (137)Cs diffusion-convection was applied to data collected from 1cm intervals in sediment cores with the aim of providing insights with respect to this element's behavior in sediments. Model results showed a significant correlation between measured and modeled values using the concentrations of (137)Cs, and estimated input into the system from the global fallout of past nuclear tests and expected values based on local sedimentation rates. Results highlight the importance of accounting for the vertical diffusion of (137)Cs in marine sediments when used as a tracer for environmental processes and for assessing potential bioavailability.
authors.affiliation: Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900, Brazil.
authors.forename: Paulo Alves de Lima
authors.initials: PA
authors.lastname: Ferreira
authors.forename: Andreza Portella
authors.initials: AP
authors.lastname: Ribeiro
authors.forename: Mylene Giseli
authors.initials: MG
authors.lastname: do Nascimento
authors.forename: Cesar de Castro
authors.initials: Cde C
authors.lastname: Martins
authors.forename: Michel Michaelovitch
authors.initials: MM
authors.lastname: de Mahiques
authors.forename: Rosalinda Carmelo
authors.initials: RC
authors.lastname: Montone
authors.forename: Rubens Cesar Lopes
authors.initials: RC
authors.lastname: Figueira
mesh_terms: D000864:Antarctic Regions; D002588:Cesium Radioisotopes / Q000032:analysis*; D019015:Geologic Sediments / Q000737:chemistry*; D012623:Seawater
chemical_list: D002588:Cesium Radioisotopes