228Ra/226Ra ratio and 7Be concentration in the Sea of Japan as indicators for water transport: comparison with migration pattern of Fukushima Dai-ichi NPP-derived 134Cs and 137Cs.
J Environ Radioact
; 126: 176-87, 2013 Dec.
Article
em En
| MEDLINE
| ID: mdl-24029140
ABSTRACT
To assess the migration patterns of radiocesium emitted from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), we analyzed (228)Ra/(226)Ra ratios and (7)Be concentrations and compared them with (134)Cs and (137)Cs concentrations in seawater samples collected within the Sea of Japan before and after the FDNPP accident (i.e., during the period 2007-2012) using low-background γ-spectrometry. The (228)Ra/(226)Ra ratios in surface waters exhibited lateral and seasonal variations, reflecting the flow patterns of surface water. This indicates the transport patterns of the FDNPP-derived radiocesium by surface water. Cosmogenic (7)Be (half-life 53.3 d) exhibited markedly high concentrations (5-10 mBq/L) at depths shallower than 50 m, with concentrations decreasing steeply (0.2-2 mBq/L) at depths of 50-250 m. The distribution of (7)Be concentrations suggests that the downward delivery of the FDNPP-derived radiocesium to below 50 m depth was negligible for a few months prior to its removal from the Sea of Japan.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Água do Mar
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Poluentes Radioativos da Água
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Berílio
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Radioisótopos de Césio
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Monitoramento de Radiação
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Rádio (Elemento)
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Acidente Nuclear de Fukushima
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article