Natural and man-made radionuclides in sediments of an inlet in Rio de Janeiro State, Brazil

• Published in: Marine pollution bulletin Vol. 107; no. 1; pp. 269 - 276
• Main Authors: Carvalho, Franciane Martins de, Lauria, Dejanira da Costa, Ribeiro, Fernando Carlos Araújo, Fonseca, Rafael Tonelli, Peres, Sueli da Silva, Martins, Nádia Soido Falcão
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.06.2016
• Subjects: Bays; Brazil; cation exchange capacity; cesium; cobalt; Geochemical mapping; geographical distribution; Geologic Sediments - analysis; Inlet; Marine; organic matter; Radioisotopes - analysis; Radionuclides; risk; sediments; silt fraction; sulfates; Surface sediments; water pollution; Brazil; ASW, Brazil, Rio de Janeiro; ASW, Brazil, Rio de Janeiro, Angra dos Reis, Ribeira Bay; Brazil; Surface sediments; Radionuclides; Geochemical mapping; Inlet
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2016.03.059

The distribution of natural radionuclides 226Ra, 228Ra, 40K and man-made radionuclides (54Mn, 60Co 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 226Ra, 228Ra and 40K, respectively. Natural radionuclide concentrations tend to be higher in the silt fraction, which determines their pattern distributions. Only one sample presented measurable concentration for 137Cs, while 54Mn was detected in two samples and 60Co 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. •A baseline of natural radionuclides in a coastal inlet was assessed.•Man-made radionuclide concentrations were evaluated in bottom sediments.•Silt fraction determines the pattern distributions of natural radionuclides.•The radioactivity level in the inlet was in normal range.•Man-made radionuclides present a dose external lower than the normal background.