From Chernobyl to Fukushima:introduction

Conveners of GI1.4 sessionM. Yamauchi (Swedish Institute of Space Physics, Sweden)

Oleg Voitsekhovych (Ukrainian Hydrometeorological Institute, Ukraine)

Elena Korobova (Vernadsky Institute of Geochemistry and AnalyticalChemistry, 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, JointResearch Center, Environment Institute, Institute ofGlobal Climate and Ecology; Roshydromet;Minchernobyl; Belhydromet)

Cesium Deposition on Europe, 1986

From Chernobyl to Fukushima: introduction

• Environment / Geoscience aspectWithout 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, bindetc)

Biochemicaltransfer andconcentration

How easy toresolve in water

Aerosol Physics/Chemistry

(a)(b)

(c)

(a) (b) (c)example: Three typesof fallout

Þ Different science chemistry &physics involve for the furthermovement of the radionuclides

Our GI1.4 session covers:1 Radionuclide release and deposition (contamination)

Aerosol physics-chemistryAtmospheric transportSurface contamination (fallout)

2 Land environment (contamination & countermeasures)(Urban), Agriculture, Forest (=Soil-system & Ecosystem)

3 Aquatic environment (contamination & countermeasures)oceanhydrology (river, lake, ground water)hydrology-soil system

4 Future tasks (research & technology)monitoring & soil experiment tasksremote sensing & unmanned vehicle technologyhealth 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

80km

Features Chernobyl FukushimaAtmosphericrelease 137Cs

90Sr 239-240Pu

IAEA, 20064785

0,03

NISA Report, 201115

0,14n/a

Atmosphericdeposition

Fuel particles, volatile and non-volatile elements

Volatile elements only

Depositionareas

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 effectsnegligible

Prevailingpathwaysof exposure

External exposure,Consumption of milk and meat,vegetables

External exposure,Consumption of milk andmeat, Vegetables, Seafood

The water pathways are not major cause in human dose exposure, but itsrole 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).

137Cs activity concentration in differentrivers per unit of deposition (Smith, 2004)

(1)

(2) (3)

(4)

(5)

(6)

Radioactive contamination of thecatchments after Chernobyl

Years

0.00001

0.0001

0.001

0.01

0.1

0 5 10 15

Time since Chernobyl (yrs)

137C

s i

n w

ate

r p

er

Bq

m-2

of

fallo

ut

(m-1

)

Kymijoki

Kokemaenjoki

Oulujoki

Kemijoki

Tornionjoki

Dora Baltea

Dnieper

Sozh

Iput

Besed

Pripyat (Mozyr)

Danube

Pripyat (Cher.)

depends on the type of fallout(physical and chemical forms of 1-6in the left are different), physicaland chemical forms the catchment,and the landscapes at thedeposited river watersheds Þ Thedetermine aquatic environment

In Chernobyl case, fallout towide variability type of soilsin BE,RU,UA, Europe

Mobility and bioavailability ofradionuclides are determinedby ratio of (1) radionuclidechemical forms in fallout and(2) site-specific environmentalcharacteristics. Theydetermines (a) rates ofleaching, (b) fixation/remobilization, and (c)sorption-desorption of mobilefraction (its solid-liquiddistribution).

Specificity of soils in Japan

• Andosols (soils developed onvolcanic ash) – 16 % of soils• Paddy soils (waterloggedsoils): most rice = paddy rice

So far, knowledge is limited on thradiocesium behavior in andosolsand waterlogged paddy soils

–Andosols: low in clay, highin organic matter–Paddy soils: under reducedconditions generation of NH4

+

which increases Cs mobilityand bioavailability

Speciation of soils and radionuclides behavior

Radionuclide mobile forms in depositionRadionuclide mobile forms in deposition

Chernobyl 90Sr* 30-km zone 10~20 %

cf. Nuclear Tests 80~90 %

Fukushuma ???

Chernobyl 137Cs* 30-km zone 20~30 %* Bryansk region 40~60 %* Cumbria, UK ~85 %(Hilton, 1992)

cf. Nuclear Tests >80 %

Fukushuma ???

Ratio of 90Sr and 137Cs in solubleforms in Pripyat river near Chernobyl

* The 137Cs concentrationin river water is proportionalto the relative fraction of itsexchangeable form in thesurface soil layer.

* The monitoring dataallowed to validatemathematical models

Rain floodSpring flood

Spring floodSpring floodWinter ice jam

0

0,3

0,6

0,9

1,2

0 5 10 15

Time, yr

13

7C

s,

Bq

.L-1

Uzh

Irpen

Teterev

Radionuclides in rivers at theChernobyl affected zone

Annual averaged 137Csin the Dnieper River

1012 Bq Radionuclide inlet to theKiev reservoir (Pripyat river)

Upper part of Kiev Reservoir

1994

Dnie

per

riverPripyatriver

Data of UHMI

Low part of Kiev Reservoir

137Cs

⇔ Several high floodsremoved Cs-137 inbottom sedimenttogether with thesediment particles(upper part depositedarea) to thedownstream of theKiev reservoir1998

1994

Kiev Reservoir

Sedimentation removes Sedimentation removes 137 137Cs from theCs from thewater column to the bottom sedimentswater column to the bottom sediments

1991-1993

2009

A bit special for 90Sr(fuel particle and ground water)

Fuel particle resolve in longtime scale, emitting 90Sr

Ground water process is veryslow, causing increase of90Sr (but not risky level)

0 500 1000 1500 2000

0-0.15

0.30-0.50

0.70-0.90

1.00-1.20

1.40-1.60

1.80-2.00

2.25-2.50

2.75-3.00

137 Cs activity, Bq/kg

Sli

ce,

cm

1963 (66)

1986 (89)

0 10 20 30

0

50

100

150

200

0 200 400 600 800 1000

C(z)=C0+a/(1+exp(-(z-z0)/b))

R = 0.91 St. Error = 2.61

Dep

th, m

TOTAL

INVENTORY

(0-200m layer) -

1173+/-181 TBq

137Cs, Bq m

-3

137Cs, TBq

- BS98-16

- BS2K-37

Stations:

After Chernobyl, the 137Cs inventory inthe 0-50 m layer increased by a factor of6-10 and the total 137Cs inventory in thewhole BS basin increased by a factor ofat least 2 (from 1.4±0.3 PBq).

137Cs input from the rivers (0.05 PBq at1986-2000) was small compard to theatmospheric fallout

137Cs-137 in the Black Sea

137Csdept

h

Information on radionuclide deposition levelsalone is not enough to accurately predictfuture and to assess human dose. Data onspeciation in fallout, rates of transformationprocesses and site-specific environmentalcharacteristics determining these rates areneeded.

Information on radionuclide chemical forms,their transformation in other words mobilityand bioavailability should be taken intoaccount when decontamination and remediationstrategies are developed on local or regionalscale.

Main messages from Chernobyl soil-water studies

Artificial rain simulation in Ukraine

Natural erosion study inFukushima

Prof. Y.Onda

• Experimental studies of the wash-offprocess (liquid and particulate phaseerosion from the contaminated lands)

⇒ Input parameter to mathematical modelsfor radionuclide runoff prediction aftersnowmelt and rains.

• Long-history experience for Chernobylcase (e.g., radionuclides wash-off byrainfall and snowmelt surface runoff)

⇒ should be used for Fukushima.

• These studies were conducted in Ukrainethe contaminated territories on the runoffplots of 1 m2 to 1000 m2.

• Currently, similar experimental studies isbeing carried out in Japan to assess theerosion and radionuclide runoff fromcontaminated paddy and agricultural lands

Experiments on runoff plots

extra slides for questions

From Chernobyl to Fukushima: introduction

From Chernobyl to Fukushima: introduction

(IAEA, 2006)

Food product, milk water external inhalation

Actual dose

Public perception about

Dose realization (%) during a 70years 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,Soon after the Chernobyl Accident,many many very expensive actionsvery expensive actions was wasapplied to reduce secondaryapplied to reduce secondarycontamination of the rivers andcontamination of the rivers andgroundwater groundwater (for drinking water).(for drinking water).But But they were ineffective.they were ineffective.

Inadequate Radiation Risk Perception by PublicInadequate Radiation Risk Perception by Public was a key was a keyreason in reason in WATER PROTECTION ACTION PLANWATER PROTECTION ACTION PLAN implementing implementing

Although the estimate doseswere very low, public hadinadequate perception of therisks of using water fromcontaminated aquaticsystems.

This factor “reduce Publicstressing” justifies limitedwater remediation actions

From Chernobyl to Fukushima: introduction

(IAEA, 2006)