title: Natural and man-made radionuclides in sediments of an inlet in Rio de Janeiro State, Brazil.
abstract: The distribution of natural radionuclides (226)Ra, (228)Ra, (40)K and man-made radionuclides ((54)Mn, (60)Co and (137) Cs) in the surface sediments of an inlet of Ribeira Bay were investigated. Sediment samples were collected and analyzed for radionuclides, organic matter, carbonate, sulfate, cationic exchange capacity and grain size composition. The natural radionuclide concentrations ranged from 4.4 to 45, from 10 to 93, from 66 to 1347Bq·kg(-1) dry weight for (226)Ra, (228)Ra and (40)K, respectively. Natural radionuclide concentrations tend to be higher in the silt fraction, which determines their pattern distributions. Only one sample presented measurable concentration for (137)Cs, while (54)Mn was detected in two samples and (60)Co in four sediment samples. Man-made radionuclides present a maximum value of dose external four times lower than the normal background and the potential risk due to the presence of man-made radionuclides in sediments is lower than the risk provided by the natural radionuclides.
authors.affiliation: Institute of Radiation Protection and Dosimetry (IRD), Av. Salvador Allende s/n - Barra da Tijuca, Rio de Janeiro - RJ, 22783-127, Brazil. Electronic address: francian@ird.gov.br.
authors.forename: Franciane Martins de
authors.initials: FM
authors.lastname: Carvalho
authors.affiliation: Institute of Radiation Protection and Dosimetry (IRD), Av. Salvador Allende s/n - Barra da Tijuca, Rio de Janeiro - RJ, 22783-127, Brazil.
authors.forename: Dejanira da Costa
authors.initials: DDC
authors.lastname: Lauria
authors.affiliation: Institute of Radiation Protection and Dosimetry (IRD), Av. Salvador Allende s/n - Barra da Tijuca, Rio de Janeiro - RJ, 22783-127, Brazil.
authors.forename: Fernando Carlos Araújo
authors.initials: FCA
authors.lastname: Ribeiro
authors.affiliation: Institute of Radiation Protection and Dosimetry (IRD), Av. Salvador Allende s/n - Barra da Tijuca, Rio de Janeiro - RJ, 22783-127, Brazil.
authors.forename: Rafael Tonelli
authors.initials: RT
authors.lastname: Fonseca
authors.affiliation: Institute of Radiation Protection and Dosimetry (IRD), Av. Salvador Allende s/n - Barra da Tijuca, Rio de Janeiro - RJ, 22783-127, Brazil.
authors.forename: Sueli da Silva
authors.initials: SDS
authors.lastname: Peres
authors.affiliation: Institute of Radiation Protection and Dosimetry (IRD), Av. Salvador Allende s/n - Barra da Tijuca, Rio de Janeiro - RJ, 22783-127, Brazil.
authors.forename: Nádia Soido Falcão
authors.initials: NSF
authors.lastname: Martins
mesh_terms: D061006:Bays; D001938:Brazil; D019015:Geologic Sediments / Q000032:analysis*; D011868:Radioisotopes / Q000032:analysis*
chemical_list: D011868:Radioisotopes
keywords: Brazil; Geochemical mapping; Inlet; Radionuclides; Surface sediments