Transcript Slide 1

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
Cesium Deposition on Europe, 1986
©Soviet Authorities
by GRID-Arendal (©European Commission, Joint
Research Center, Environment Institute, Institute of
Global Climate and Ecology; Roshydromet;
Minchernobyl; Belhydromet)
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
Fluid Dynamics and Transport
Aerosol Physics/Chemistry
Chemical property
(ionized, exited, bind
etc)
Biochemical
transfer and
concentration
How easy to
resolve in water
(Shestopalov et al., 2003)
(c)
(b)
(a)
example: Three types
of fallout
Different science chemistry &
physics involve for the further
movement of the radionuclides
(a)
(b)
(c)
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
Comparison of Fukushima & Chernobyl
(same scale)
80km
80km
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
Speciation and similarities of the impacts
Features
Chernobyl
Fukushima
Atmospheric
release 137Cs
90Sr
239-240Pu
IAEA, 2006
NISA Report, 2011
15
0,14
n/a
Atmospheric
deposition
Fuel particles, volatile and non- Volatile elements only
volatile elements
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
47
85
0,03
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)
(1)
Radioactive contamination of the
catchments after Chernobyl
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).
-1
of fallout (m
0.1
Kymijo ki
Ko kemaenjo ki
Oulujo ki
0.01
Kemijo ki
To rnio njo ki
-2
(5)
Cs in water per Bq m
(4)
137
(6)
)
(3)
(2)
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
Do ra B altea
Dnieper
0.001
So zh
Iput
B esed
P ripyat (M o zyr)
0.0001
Danube
P ripyat (Cher.)
0.00001
0
5
10
Time since Chernobyl (yrs)
137Cs
15
Years
activity concentration in different
rivers per unit of deposition (Smith, 2004)
Speciation of soils and radionuclides behavior
Specificity of soils in Japan
• Andosols (soils developed on
volcanic ash) – 16 % of soils
• Paddy soils (waterlogged
soils): most rice = paddy rice
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
So far, knowledge is limited on th chemical forms in fallout and
radiocesium behavior in andosols
(2) site-specific environmental
and waterlogged paddy soils
characteristics. They
–Andosols: low in clay, high
determines (a) rates of
in organic matter
leaching, (b) fixation/
–Paddy soils: under reduced
remobilization, and (c)
+
conditions generation of NH4
sorption-desorption of mobile
which increases Cs mobility
fraction (its solid-liquid
and bioavailability
distribution).
Radionuclide mobile forms in deposition
Chernobyl 137Cs
Chernobyl 90Sr
* 30-km zone
* Bryansk region
* Cumbria, UK
(Hilton, 1992)
20~30 % * 30-km zone
40~60 %
~85 %
10~20 %
cf. Nuclear Tests
>80 %
cf. Nuclear Tests
80~90 %
Fukushuma
???
Fukushuma
???
Radionuclides in rivers at the
Chernobyl affected zone
Annual averaged 137Cs in
Uzh
the Dnieper River
Cs, Bq.L -1
0,9
137
1,2
0,3
Ratio of 90Sr and 137Cs in soluble
forms in Pripyat river near Chernobyl
Irpen
Teterev
0,6
0
0
5
10
15
Time, yr
1012 Bq Radionuclide inlet to the
Kiev reservoir (Pripyat river)
* The 137Cs 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
Sedimentation removes 137Cs from the
water column to the bottom sediments
Upper part of Kiev Reservoir
1998
 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
Low part of Kiev Reservoir
137Cs
1994
1994
Kiev Reservoir
1991-1993
2009
Data of UHMI
A bit special for 90Sr
(fuel particle and ground water)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Fuel particle resolve in long
time scale, emitting 90Sr
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Ground water process is very
slow, causing increase of
90Sr (but not risky level)
137Cs-137
in the Black Sea
0
0
137
200
400
10
137
Cs, TBq
600
800
Cs, Bq m-3 20
1000
30
0
TOTAL
INVENTORY
depth
(0-200m layer) 1173+/-181 TBq
50
100
Depth, m
137Cs
150
200
137

Cs activity, Bq/kg
0
500
1000
1500
2000
0-0.15
0.30-0.50
1986 (89)
Slice, cm
0.70-0.90
1.00-1.20
C(z)=C0+a/(1+exp(-(z-z0)/b))
R = 0.91 St. Error = 2.61
Stations:
- BS98-16
- BS2K-37
After Chernobyl, the 137Cs inventory in
the 0-50 m layer increased by a factor of
6-10 and the total 137Cs inventory in the
whole BS basin increased by a factor of
at least 2 (from 1.4 0.3 PBq).
1.40-1.60
1.80-2.00
2.25-2.50
2.75-3.00
1963 (66)

137Cs
input from the rivers (0.05 PBq at
1986-2000) was small compard to the
atmospheric fallout
Main messages from Chernobyl soil-water studies
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.

Prof. Y.Onda
Experiments on runoff plots
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.
•
Natural erosion study in
Fukushima
•
These studies were conducted in Ukraine
the contaminated territories on the runoff
plots of 1 m2 to 1000 m2.
Currently, similar experimental studies is
being carried out in Japan to assess the
erosion and radionuclide runoff from
Artificial rain simulation in Ukrainecontaminated paddy and agricultural lands
•
soil / ecosystem
First, we have to sample.
Vertical migration of radionuclide over time
(1) Initial phase
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
(2) After some time
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.
Bq/cm2
Bq/cm2
2005
2011
Vertical distribution of Cs-137 in the podzolic soil (Original)
Distribution of radionuclides
in terrestrial & forest
ecosystems
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
Evaluation of secondary redistribution
Gamma-emitters distribution in the Khocheva river
basin, 45 km south from the ChNPP.
10
6
3-5
1
7-9
2
11
Evaluation of secondary redistribution (take
difference between the percent of activity due to
one-year decay and the really measured values)
 Non-uniform
Spatial structure of Cs-137 contamination field.
A stable fractal polycentric structure was proved by measurements within the nested
regular grid and along the transverse and lengthwise cross-sections
Transfer in soil-plant system and its dynamics
depending upon the fallout, soil type and humidity
From Shcheglov, Tsvetnova, Klyashtorin, 2005
137Cs
and 131I contamination and 127I status of the soil cover estimate (Bryansk, Kaluga,
Orel, Tula regions region)
Relation between the 131I density of the soil on May 15, 1986 and the
of total 137Cs density of the soil:
131I=3.77(137Cs-137Cs )0.847, where 137Cs =0.056 Ci/km2
b
b
UNSCEAR, 2000
Makhon’ko K.P. et al. Atomnaya
Energiya, 1992, 72, 4, 377-382
1:1000000
extra slides for questions
Inadequate Radiation Risk Perception by Public was a key
reason in WATER PROTECTION ACTION PLAN implementing
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.
Dose realization (%) during a 70
years for children born in 1986
For 1-st year about 47 %
For 10 years about 80%
Years
(I. Los, O. Voitsekhovych, 2001)
Actual dose
Public perception about
Food product, milk
water
external
inhalation
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
137Cs
contamination (Kashparov et al., 2003)
From Chernobyl to Fukushima: introduction
From Chernobyl to Fukushima: introduction
(IAEA, 2006)