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Radiocesium wash-off, river transport and redistribution in fluvial system after the Fukushima Dai-ichi nuclear power plant accidentтезисы доклада
- Авторы: Konoplev A., Wakiyama Yu, Wada T., Golosov V., Ivanov M., Komissarov M., Kanivets V., Udy C., Niida T., Moritaka S., Usuki M., Watanabe K., Takase T., Goto A., Tsukada H., Nanba K.
- Сборник: European Geosciences Union General Assembly 2020
- Тезисы
- Год издания: 2020
- Издательство: Copernicus GmbH on behalf of the European Geosciences Union
- Местоположение издательства: Germany
- Номер статьи: EGU2020-3245
- DOI: 10.5194/egusphere-egu2020-3245
- Аннотация: P rocesses responsible for long-term changes in environmental radioactivity after the Fukushimaaccident are currently high on the agenda. Dynamics of particulate and dissolved radiocesium (r-Cs) has been studied on a number of water bodies, namely Abukuma River, Niida River and MaedaRiver, the dam reservoirs of Yokokawa (Ota River), Sakashita (Kuma River), Ogaki (Ukedo River) andShinobu (Abukuma River) and four heavily contaminated irrigation ponds in Okuma town(Inkyozaka, Suzuuchi, Funasawa, Kashiramori). Water samples were collected for dissolved andparticulate r-Cs analysis at multiple sites for these water bodies. Wash-off from slopes ofcontaminated catchments and river transport are key long-term pathways for radionuclidedispersal from contaminated areas after the Fukushima accident. The climate and geographicalconditions for the Fukushima Prefecture of Japan are characterized by relatively high annualprecipitation (1300-1800 mm/year) and steep slopes which promote higher erosion and higherparticulate r-Cs wash-off. At the same time, the r-Cs distribution coefficientin Fukushima riversKdwas found to be at least an order of magnitude higher than the corresponding values forChernobyl-derived r-Cs and r-Cs resulting from nuclear weapon tests (NWT) in European rivers.The normalized dissolved wash-off coefficient for Fukushima river watersheds, based on themeasured dissolved r-Cs activity concentrations was found to be 1-2 orders of magnitude lowerthan those for Chernobyl and NWT fallout. In the irrigation ponds r-Cs showed a persistentbehavior and was characterized by regular seasonal variations: r-Cs concentrations tend to growduring summer and decrease during winter. Speciation analysis for Okuma ponds showed a muchhigher exchangeability of r-Cs in bottom sediments than catchment soils. Several methodologiesto collect water samples and to separate the particulate and dissolved fractions have been usedand showed comparable results for all water bodies under study. For all rivers, reservoirs, andponds higher values ofKd(r-Cs) have been confirmed when compared with Chernobyl-derived r-Cs
- Добавил в систему: Голосов Валентин Николаевич