Tracing the dispersion of sediment contaminated with radionuclides in catchments exposed to Chernobyl and Fukushima fallout

O. Evrard (1, 2) , Vladimir Belyaev (3) , Caroline Chartin (1, 2) , Catherine Ottle (1, 4) , Nadezda Ivanova (3) , Maxim Markelov (3) , Irène Lefevre (1, 2) , Valentin Golosov (3) , Philippe Bonté (1, 2)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 GEDI - Géochimie Des Impacts
3 MSU - Lomonosov Moscow State University
4 MOSAIC - Modélisation des Surfaces et Interfaces Continentales

The Chernobyl and Fukushima nuclear power plant accidents led to the release of large quantities of radionuclides into the environment. Several of those radionuclides (e.g. 134Cs and 137Cs) strongly sorb onto soil particles. Once delivered to rivers by erosion processes and runoff, sediment redistribution can lead to the progressive dispersion of radioactive contamination into larger areas over time. This paper deals with case studies conducted in Russia (the 2000 km² River Plava catchment affected by Chernobyl fallout in 1986), and in Japan (the 5000 km² highly contaminated area of Fukushima Prefecture). A key prerequisite for undertaking studies of the subsequent redistribution of contaminated sediment in catchments and river systems is a good knowledge of the initial spatial pattern of soil contamination by fallout radionuclides. In this contribution, we check the local validity of the initial contamination map provided for the Russian case study site and outline the implications for conducting a similar study in Japan.

Keywords: fallout radionuclides; sediment tracing; nuclear accident; redistribution of contaminated sediment; catchment; agriculture

Domains: Environmental Sciences; Global Changes; Continental interfaces, environment; Geomorphology; Hydrology; Soil study

O. Evrard, Vladimir Belyaev, Caroline Chartin, Catherine Ottle, Nadezda Ivanova, et al.. Tracing the dispersion of sediment contaminated with radionuclides in catchments exposed to Chernobyl and Fukushima fallout. Erosion and Sediments Yields in the Changing Environment (Proceedings of a symposium held at the Institute of Mountain Hazards and Environment, CAS-Chengdu, China, 11–15 October 2012), IAHS Publ. 356, 2012. ⟨cea-02615661⟩