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| Titel |
The Project on the distribution of fallout radionuclide and their transfer through environment by Fukushima Daiichi NPP accident |
| VerfasserIn |
Yuichi Onda, Hiroaki Kato, Kazuya Yoshimura, Takehiko Fukushima, Jérémy Patin |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250084755
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| Zusammenfassung |
| Radioactive contamination has been detected in Fukushima due to the nuclear accident
at Fukushima Daiichi Nuclear Power Plant (NPP) following the earthquake and
tsunami on 11 March 2011. Following comprehensive investigation (FMWSE project
funded by MEXT, Japan; http://fmwse.suiri.tsukuba.ac.jp/) was conducted to confirm
migration of radionuclides through natural environment including soils and rivers.
Experimental catchments have been established in Yamakiya district, Kawamata
Town, Fukushima prefecture, located about 35 km from Fukushima power plant, and
designated as the evacuated zone. Approximate Cs-137 fallout in this area is 200 - 600
kBq/m2.
(1) Migration study of radionuclides in natural environment including forests and
rivers:
  1) Depth distribution of radiocaesium in soils within forests, fields, and
grassland,
  2) Confirmation of radionuclide distribution and investigation on migration in
forests,
  3) Study on radionuclide migration due to soil erosion under different land
use,
  4) Measurement of radionuclides entrained from natural environment including
forests and soils.
(2) Migration study of radionuclides through hydrological cycle such as soil water, rivers,
lakes and ponds, ground water:
  1) Investigation on radionuclide migration through soil water, ground water, stream
water, spring water under different land use,
  2) Study on paddy-to-river transfer of radionuclides through suspended
sediments,
  3) Study on river-to-ocean transfer of radionuclides via suspended sediments,
  4) Confirmation of radionuclide deposition in ponds and reservoirs.
The main finding is as follows:
1) Migration of radionuclides to soil water, stream water and ground water was confirmed
low at present. On the other hand, concentration of radiocaesium was found approximately 50
kBq/kg in the suspended sediments flowing down the river.
2) Amount of sediments deposited in the tank placed at the end of downstream within the
USLE plot was confirmed together with the concentrations of radiocaesium.
3) In forests, distribution of radiocaesium was able to be confirmed to a certain extent by
placing towers in the Japanese cedar forest and broad-leaved forest. To date, since a large
amount of radiocaesium is considered to be found in coniferous tree canopies, these data are
expected to be applied to future decontamination. Moreover, further investigation is necessary
on the chemical state of radiocaesium which falls down to the forest floor as through fall and
on the actual condition of downward migration from forest floor to deeper soil layers. |
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