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)