From Chernobyl to Fukushima: introduction Conveners of GI1.4 session M. Yamauchi (Swedish Institute of Space Physics, Sweden) Oleg Voitsekhovych (Ukrainian Hydrometeorological Institute, Ukraine) Elena Korobova (Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Federation) Michio Aoyama (Meteorological Research Institute, Japan) Kazuyuki Kita (Ibaraki University, Japan) Andreas Stohl (Norwegian Institute for Air Research, Norway) Gerhard Wotawa (Central Inst. Meteorology and Geodynamics, Austria) Naohiro Yoshida (Tokyo Institute of Technology, Japan)

From Chernobyl to Fukushima: introduction ©Soviet Authorities by GRID-Arendal (©European Commission, Joint Research Center, Environment Institute, Institute of Global Climate and Ecology; Roshydromet; Minchernobyl; Belhydromet) Cesium Deposition on Europe, 1986

From Chernobyl to Fukushima: introduction Environment / Geoscience aspect Without understanding contamination science, we cannot estimate or protect human exposure Multi-disciplinary aspect - Dynamics / Physics / Chemistry / Biology - Local / Regional / Global - Urban / Field / Forest / Water / Ocean Multiple-route effects of radionuclide - External & internal dose - Physical & biological/environmental decay - Hardness of radiation (mainly gamma)

Many sciences are involved (Shestopalov et al., 2003) Fluid Dynamics and Transport Chemical property (ionized, exited, bind etc) Biochemical transfer and concentration How easy to resolve in water Aerosol Physics/Chemistry

(a) (b) (c) (a)(b)(c) example: Three types of fallout  Different science chemistry & physics involve for the further movement of the radionuclides

Our GI1.4 session covers: 1 Radionuclide release and deposition (contamination) Aerosol physics-chemistry Atmospheric transport Surface contamination (fallout) 2 Land environment (contamination & countermeasures) (Urban), Agriculture, Forest (=Soil-system & Ecosystem) 3 Aquatic environment (contamination & countermeasures) ocean hydrology (river, lake, ground water) hydrology-soil system 4 Future tasks (research & technology) monitoring & soil experiment tasks remote sensing & unmanned vehicle technology health risk modeling (e.g., GIS modeling) risk analyses in general

Fukushima contamination is: - comparable Cs-deposition levels but over smaller area - no substantial Sr, Am, Pu deposition via atmospheric releases - however, much larger releases to the sea Comparison of Fukushima & Chernobyl (same scale) 80km

FeaturesChernobylFukushima Atmospheric release 137 Cs 90 Sr Pu IAEA, ,03 NISA Report, ,14 n/a Atmospheric deposition Fuel particles, volatile and non- volatile elements Volatile elements only Deposition areas Mainly central Europe: Terrestrial ecosystems, Catchments of the Dnieper & Danube river basin, Forest and agriculture areas, Black Sea and Baltic Sea. * Huge transboundary effect Pacific coast of Japan: Complex landscape, Forest, agricultural area, High density of population, Ocean ecosystem. * Transboundary effects negligible Prevailing pathways of exposure External exposure, Consumption of milk and meat, vegetables External exposure, Consumption of milk and meat, Vegetables, Seafood The water pathways are not major cause in human dose exposure, but its role are significant in some cases (e.g., specific water use such as irrigation, water supply, fishery and seafood production) Speciation and similarities of the impacts

Calculated plume formation (GMT): (1) 26 April, 00:00; (2) 27 April, 00:00; (3) 27 April, 12:00; (4) 29 April, 00:00; (5) 2 May, 00:00; and (6) 4 May, 12:00 (Borsilov and Klepikova 1993). 137 Cs activity concentration in different rivers per unit of deposition (Smith, 2004) (1) (2) (3) (4) (5) (6) Radioactive contamination of the catchments after Chernobyl Years depends on the type of fallout (physical and chemical forms of 1-6 in the left are different), physical and chemical forms the catchment, and the landscapes at the deposited river watersheds  The determine aquatic environment

Specificity of soils in Japan Andosols (soils developed on volcanic ash) – 16 % of soils Paddy soils (waterlogged soils): most rice = paddy rice So far, knowledge is limited on th radiocesium behavior in andosols and waterlogged paddy soils –Andosols: low in clay, high in organic matter –Paddy soils: under reduced conditions generation of NH 4 + which increases Cs mobility and bioavailability In Chernobyl case, fallout to wide variability type of soils in BE,RU,UA, Europe Mobility and bioavailability of radionuclides are determined by ratio of (1) radionuclide chemical forms in fallout and (2) site-specific environmental characteristics. They determines (a) rates of leaching, (b) fixation/ remobilization, and (c) sorption-desorption of mobile fraction (its solid-liquid distribution). Speciation of soils and radionuclides behavior

Radionuclide mobile forms in deposition Chernobyl 137 Cs * 30-km zone 20~30 % * Bryansk region 40~60 % * Cumbria, UK ~85 % (Hilton, 1992) cf. Nuclear Tests >80 % Fukushuma ??? Chernobyl 90 Sr * 30-km zone 10~20 % cf. Nuclear Tests 80~90 % Fukushuma ???

Ratio of 90 Sr and 137 Cs in soluble forms in Pripyat river near Chernobyl * The 137 Cs concentration in river water is proportional to the relative fraction of its exchangeable form in the surface soil layer. * The monitoring data allowed to validate mathematical models Rain flood Spring flood Winter ice jam Radionuclides in rivers at the Chernobyl affected zone Annual averaged 137 Cs in the Dnieper River Bq Radionuclide inlet to the Kiev reservoir (Pripyat river)

Upper part of Kiev Reservoir 1994 Dnieper river Pripyat river Data of UHMI Low part of Kiev Reservoir 137 Cs  Several high floods removed Cs-137 in bottom sediment together with the sediment particles (upper part deposited area) to the downstream of the Kiev reservoir Kiev Reservoir Sedimentation removes 137 Cs from the water column to the bottom sediments Sedimentation removes 137 Cs from the water column to the bottom sediments

A bit special for 90 Sr (fuel particle and ground water) Fuel particle resolve in long time scale, emitting 90 Sr Ground water process is very slow, causing increase of 90 Sr (but not risky level)

After Chernobyl, the 137 Cs inventory in the 0-50 m layer increased by a factor of 6-10 and the total 137 Cs inventory in the whole BS basin increased by a factor of at least 2 (from 1.4  0.3 PBq). 137 Cs input from the rivers (0.05 PBq at ) was small compard to the atmospheric fallout 137 Cs-137 in the Black Sea 137 Cs depth

Information on radionuclide deposition levels alone is not enough to accurately predict future and to assess human dose. Data on speciation in fallout, rates of transformation processes and site-specific environmental characteristics determining these rates are needed. Information on radionuclide chemical forms, their transformation in other words mobility and bioavailability should be taken into account when decontamination and remediation strategies are developed on local or regional scale. Main messages from Chernobyl soil-water studies

Artificial rain simulation in Ukraine Natural erosion study in Fukushima Prof. Y.Onda Experimental studies of the wash-off process (liquid and particulate phase erosion from the contaminated lands)  Input parameter to mathematical models for radionuclide runoff prediction after snowmelt and rains. Long-history experience for Chernobyl case (e.g., radionuclides wash-off by rainfall and snowmelt surface runoff)  should be used for Fukushima. These studies were conducted in Ukraine the contaminated territories on the runoff plots of 1 m 2 to 1000 m 2. Currently, similar experimental studies is being carried out in Japan to assess the erosion and radionuclide runoff from contaminated paddy and agricultural lands Experiments on runoff plots

soil / ecosystem First, we have to sample.

Empirical evidence suggests a relatively rapid infiltration of radionuclides during and shortly after (weeks and months) the fallout. Most part of radionuclides at that time was observed in the top 5-cm soil layer. Vertical migration of radionuclide over time (1) Initial phase

Vertical distribution of Cs-137 in the podzolic soil (Original) Vertical migration of radionuclide over time (2) After some time Bq/cm 2 Downward migration continued in the following period of long-term secondary redistribution and the thickness of the layer containing a major portion of contamination increased but in most cases it did not reach 15 cm depth and was potentially available for root uptake by plants for long period.

Distribution of radionuclides in terrestrial & forest ecosystems

(Shaw et al., 2002)

Distribution of radionuclides in terrestrial & forest ecosystems From Shcheglov, Tsvetnova, Klyashtorin, 2005

Distribution of radionuclides in terrestrial & forest ecosystems Species and mobility in soils From Shcheglov, Tsvetnova, Klyashtorin, 2005

Gamma-emitters distribution in the Khocheva river basin, 45 km south from the ChNPP. Evaluation of secondary redistribution Evaluation of secondary redistribution (take difference between the percent of activity due to one-year decay and the really measured values)  Non-uniform

A stable fractal polycentric structure was proved by measurements within the nested regular grid and along the transverse and lengthwise cross-sections Spatial structure of Cs-137 contamination field.

From Shcheglov, Tsvetnova, Klyashtorin, 2005 Transfer in soil-plant system and its dynamics depending upon the fallout, soil type and humidity

1: Relation between the 131 I density of the soil on May 15, 1986 and the of total 137 Cs density of the soil: 131 I=3.77( 137 Cs- 137 Cs b ) 0.847, where 137 Cs b =0.056 Ci/km 2 UNSCEAR, 2000 Makhon’ko K.P. et al. Atomnaya Energiya, 1992, 72, 4, Cs and 131 I contamination and 127 I status of the soil cover estimate (Bryansk, Kaluga, Orel, Tula regions region)

extra slides for questions

Food product, milk water external inhalation Actual dose Public perception about Dose realization (%) during a 70 years for children born in 1986 (I. Los, O. Voitsekhovych, 2001) For 1-st year about 47 % For 10 years about 80% Years Soon after the Chernobyl Accident, many very expensive actions was applied to reduce secondary contamination of the rivers and groundwater (for drinking water). But they were ineffective. Inadequate Radiation Risk Perception by Public was a key reason in WATER PROTECTION ACTION PLAN implementing Although the estimate doses were very low, public had inadequate perception of the risks of using water from contaminated aquatic systems. This factor “reduce Public stressing” justifies limited water remediation actions

From Chernobyl to Fukushima: introduction (IAEA, 2006)

From Chernobyl to Fukushima: introduction 137 Cs contamination (Kashparov et al., 2003)

From Chernobyl to Fukushima: introduction

(IAEA, 2006)