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| Titel |
Differences and similarities between behavior of Fukushima-derived and Chernobyl-derived radiocesium in the environment |
| VerfasserIn |
Alexei Konoplev, Kenji Nanba, Yuichi Onda, Valentin Golosov, Yoshifumi Wakiyama, Tsugiko Takase, Vasyl Yoschenko, Mark Zheleznyak |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123054
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| Publikation (Nr.) |
 EGU/EGU2016-2232.pdf |
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| Zusammenfassung |
| The mobility and bioavailability of radiocesium (r-Cs) of accidental origin is governed by the
ratio of its chemical forms in fallout and site-specific environmental characteristics
determining the rates of leaching, fixation-remobilization, as well as sorption-desorption of
the mobile fraction (its solid-liquid distribution). R-Cs in the environment is strongly bound
to soil and sediment particles containing micaceous clay minerals (illite, vermiculite, etc.).
This is associated with two basic processes – high selective reversible sorption and
fixation.
Climate and geographical conditions for Fukushima Prefecture of Japan and Chernobyl
zone differ. For example, the catchments of the Chernobyl zone are flat and characterized by
low slopes, while Fukushima’s watersheds are hilly with steep slopes. Annual precipitation
also differs substantially, with annual average for Fukushima about 3 times higher than at
Chernobyl. The soils on the north-east coast of the Honshu island that were primarily affected
by the radioactive contamination from the Fukushima Daiichi nuclear power plant
(FDNPP) accident differ significantly from the Chernobyl zone soils. The proportion
of clays such as illite, vermiculite etc. is 20-30% at Fukushima, which is higher
than in the sandy loam soils of the Chernobyl zone. In addition to the landscape
differences, the speciation of r-Cs in fallout was also different between Fukushima and
Chernobyl.
It is a challenge to compare r-Cs behavior in FDNPP and Chernobyl zones.
Comparative analysis has been carried out for r-Cs wash-off parameters and the
distribution coefficient Kd in rivers and surface runoff on Fukushima and Chernobyl
contaminated areas for the first years after the accidents. The r-Cs distribution coefficient in
Fukushima rivers was 1-2 orders of magnitude higher than correspondent values for rivers
and surface runoff of the Chernobyl zone. This suggests higher ability of Fukushima soils and
sediments to bind r-Cs. The normalized dissolved wash-off coefficients for Fukushima river
watersheds are 1-2 orders of magnitude lower than corresponding values for the
Chernobyl zone. Normalized particulate wash-off coefficients are comparable for
Fukushima and Chernobyl. The effective dispersion coefficients in the Fukushima soils
were found to be relatively high (2-10 cm2/year) as compared to Chernobyl values.
Investigation and analysis of Fukushima-derived r-Cs distribution in soils of Niida river
catchment has led to identify accumulation zones of contaminated sediments on the
floodplain. Contaminated sediment accumulation is one of the most important factors for
predicting r-Cs redistribution on a catchment and its fluvial transport, and is also
relevant for decision making on remediation options of contaminated territories. |
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