IEDA IRMA LAMAS CUNHA
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Artigo IPEN-doc 22663 A model of recent sedimentation in the Cananeia–Iguape estuary, Brazil2006 - SAITO, R.T.; FIGUEIRA, R.C.L.; TESSLER, M.G.; CUNHA, I.I.L.Coastal systems, in particular estuaries, are the first depositional environment to receive sediments transported by rivers to the coastal ocean. As a consequence of the geochemical processes involved, a part of the sediment may be deposited in the estuary and the remainder flows into the ocean, being transported and deposited under the influence of tides and maritime currents. This study was carried out in the Cananeia–Iguape estuary on the southern coast of São Paulo state, Brazil. The vertical distribution of 210Pb and 137Cs in sediments has been used as a tool for estimating the sedimentation rates in the coastal environment. Concentrations of 210Pb and 137Cs, as well as heavy metals (lead, zinc, copper) were determined in four sediment cores collected in the Cananeia–Iguape estuary. The estimated sedimentation rates were from 5.3 mm yr−1 to 12.7 mm yr−1. The highest sedimentation rate obtained for Valo Grande corresponds with an accelerated expansion of the sand and clay banks of the Mar Pequeno channel, a growth of the mangrove areas, and a decrease in the depth of the main channel of navigation, a fact that has been affecting the navigation in the area very seriously. The data obtained for the metals showed a sedimentary dynamics in agreement with that obtained in the studies of sedimentation rates, thus contributing to the understanding of the hydrodynamic mechanisms of the system.Artigo IPEN-doc 22589 Distribution of 137Cs, 238Pu and 239 + 240Pu in sediments of the southeastern Brazilian shelf–SW Atlantic margin2006 - FIGUEIRA, RUBENS C.L.; TESSLER, MOYSES G.; MAHIQUES, MICHEL M. de; CUNHA, IEDA I.L.Resumo IPEN-doc 17431 Rate of sedimentary in the coastal systems and on the souther continental plataform of the state of São Paulo, Brazil2000 - TESSLER, M.G.; CUNHA, I.I.L.; SAITO, R.T.; FIGUEIRA, R.C.Analyses of the concentrations of the natural radionuclideos 210Pb and 226 Ra, scattered in the environment in vestigial amounts in witnesses of the coastal and occeanic areas provide a historical record of events and make it possible to estimate the background and variations in the volume of sediments laid down extensive periods of time. The results of the analyses of the rates of sedimentation obtained in the coastal systems (Cananeia-Igaupe system) and the souther continental platform of the state of São Paulo, by means of the calculation of the 210Pb and 226Ra by gama spectrometry, are presented in this study.A detector of hyperpure Germanium with a low level of bottom radiation and a study of the phototype of these radionuclideos was used for the analysis of these same radionuclideos in the marine sediments. The analysis of the 210Pb was undertaken by means of the gama emission of 47Kev and that of 226Ra by the gama emission of the Bi (609 Kev). Additionally a sedimentation rate was calculated for purposes of comparison on the basis of the levels of 137 Cs present in the witnesses, the biennium 1963/1964 being taken as the maximum pcak of atmospheric emission by nuclear explosions as from witch time on the atmospheric emission of this radionuclid diminishes and its rate of deposition on the earth’s crust is considered constant. The rates of sedimentation obtained for the coastal system show agreement of the values obtained for 210Pb (5.33mm/yr) with those obtained through the dating method for 137Cs (5.46mm/yr). The sedimentation rates obtained for the continental platform correspond to values some five times inferior to those obtained in the coastal systems.Artigo IPEN-doc 10438 Níveis de chumbo, cobre e zinco em amostras de sedimentos do sistema costeiro Cananeia-Iguape (São Paulo, Brasil)2001 - SAITO, ROBERTO T.; FIGUEIRA, RUBENS C.L.; TESSLER, MOYSES G.; CUNHA, IEDA I.L.Artigo IPEN-doc 19164 Niveis de metais pesados (Pb, Cu e Zn) na plataforma continental e talude superior do Estado de São Paulo2001 - TESSLER, MOYSES G.; FIGUEIRA, RUBENS C.L.; SAITO, ROBERTO T.; CUNHA, IEDA I.L.Resumo IPEN-doc 10413 sup(210)Pb, sup(226)Ra and sup(137)Cs levels and sedimentation rate in admiralty bay, antarctic peninsula2005 - FIGUEIRA, R.C.L.; MARTINS, C.C.; MONTONE, R.C.; FIGUEIREDO, A.M.G.; TESSLER, M.G.; MAHIQUES, M.M.; CUNHA, I.I.L.Artigo IPEN-doc 10804 sup(210)Pb and sup(137)Cs levels in marine sediment samples from the southeastern coast of Brazil, South Atlantic area2004 - FIGUEIRA, R.C.L.; TESSLER, M.G.; MAHIQUES, M.M.; ZANINI, K.; SAITO, R.T.; CUNHA, I.I.L.Artigo IPEN-doc 08787 Niveis de sup(210)Pb e sup(210)Po em aguas dos canais do Sistema Costeiro Cananeia-Iguape (Sao Paulo, Brasil)2002 - SAITO, R.T.; FIGUEIRA, R.C.L.; TESSLER, M.G.; CUNHA, I.I.L.Artigo IPEN-doc 08786 Ingestao de sup(210)Pb e sup(210)Po pelo consumo de peixes no Sistema Cananeia-Iguape, Sao Paulo, Brasil2002 - SAITO, R.T.; FIGUEIRA, R.C.L.; TESSLER, M.G.; CUNHA, I.I.L.Artigo IPEN-doc 08303 Simultaneous analysis of sup(137)Cs, sup(90)Sr, sup(238)Pu and sup(239+240)Pu in Brazilian seawater2000 - FIGUEIRA, R.C.L.; SARAIVA, E.S.B.G.; CUNHA, I.I.L.
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