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) From Chernobyl to Fukushima: introduction
Transcript
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 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)
Fukushima compared to Chernobyl: -comparable Cs-deposition levels but over smaller area-no substantial Sr, Am, Pu deposition via atmospheric releases-however, much larger releases to the sea
7
Speciation and similarities of the impactsFeatures Chernobyl Fukushima
Atmospheric release 137Cs 90Sr239-240Pu
IAEA, 2006
47
85
0,03
NISA Report, 2011
15
0,14
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 and 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
In both cases the water pathways are not prevailing in human dose exposure, however its role are significant in some cases of specific water use such as irrigation, water supply, fishery and seafood production and also can create inadequate risk perception phenomena
Calculated plume formation according to meteorological conditions for instantaneous releases on the following dates and times (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).
Radioactive contamination of the catchments after Chernobyl and aquatic environment, as versus of fallout formation date, its physical and chemical forms and also speciation of the the landscapes at the deposited river watersheds
137Cs activity concentration in different rivers per unit of deposition (Smith, 2004)
(1)
(2) (3)
(4)
(5)
(6)
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 Limited knowledge on radiocesium behavior in andosols and waterlogged paddy soils: increased availability expected
Andosols: low in clay, high in organic matterPaddy soils: under reduced conditions generation of NH4
+ which increases Cs mobility and bioavailability
In Chernobyl case fallout was covered wide variability type of soils in BE,RU,UA, Europe
Mobility and bioavailability of radionuclides are determined by ratio of radionuclide chemical forms in fallout and site-specific environmental characteristics determining rates of leaching, fixation/remobilization as well as sorption-desorption of mobile fraction (its solid-liquid distribution).
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Radionuclide mobile forms in deposition.Radionuclide mobile forms in deposition.
137Cs
Chernobyl origin30-km zone - 20-30 %
Bryansk region - 40-60 %
Cumbria, UK - 85 %(Hilton, 1992)
Nuclear Tests >80 %
90Sr
Chernobyl origin30-km zone - 10-15 %
Kyshtym - 80-90 %
Nuclear Tests >90 %
Fukushima - ?Fukushima - ?
Main messages from Chernobyl soil-water studies
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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 rehabilitation and decontamination strategies are developed on local or regional scale.
Experiments on runoff plots
Artificial rain simulation studies 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 can bring important knowledge on mathematical models parameterization to be applied for radionuclide runoff prediction after snowmelt and rains.
• Experience gained after Chernobyl has to be utilized in Fucushima affected areas as well as prior results of the study radionuclides wash-off by rainfall and snowmelt surface runoff.
• These studies were conducted in Ukraine the contaminated territories on the runoff plots of 1 m2 to 1000 m2.
• Currently similar studies carrying out in Japan aiming experimental assessment of erosion and radionuclide runoff from contaminated paddy and agricultural lands
Radionuclides in Rivers at the Chernobyl affected zone
Annual averaged 137Cs in the Dnieper River Ratio of 90Sr and 137Cs in soluble forms in Pripyat River near Chernobyl
1012 Bq Radionuclide inlet to the Kiev reservoir. Pripyat River The 137Cs concentration in river water has been shown to be directly proportional to the relative fraction of its exchangeable form in the surface soil layer. The monitoring data allowed to validate mathematical models
Rain floodSprin
g flood
Spring flo
odSpring flo
odWinter ic
e jam
0
0,3
0,6
0,9
1,2
0 5 10 15
Time, yr
13
7C
s, B
q.L
-1
Uzh
Irpen
Teterev
Sedimentation is a key factor of Sedimentation is a key factor of 137 137Cs removal Cs removal from the water column to the bottom sedimentsfrom the water column to the bottom sediments
1991-93
Upper part of Kiev Reservoir
1994
Dni
eper
Riv
er
Pripyat River
Data of UHMI
Low part of Kiev Reservoir
137Cs
Since 1991 to 2009 as result of several high floods the most of Cs-137 in bottom sediment has been removed with the sediment particles from the upper part deposited area to the down part sector of the Kiev reservoir
2009
1998
1994
Kiev Reservoir
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
137Cs activity, Bq/kg
Sli
ce
, c
m
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
Depth, m
TOTAL INVENTORY
(0-200m layer) -1173+/-181 TBq
137Cs, Bq m-3
137Cs, TBq
- BS98-16- BS2K-37
Stations:
137Cs-137 in the Black Sea
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 (pre-Chernobyl value of 1.40.3 PBq after bomb-testing fallout).
137Cs input from the Danube and the Dnieper rivers (0.05 PBq in the period 1986-2000) was insignificant in comparison with the short-term atmospheric fallout
In spite of doses were estimated to be very low, there was an inadequate perception of the real risks by Public using water from contaminated aquatic systems.
This factor made reasonable to justify some set of limited water remediation actions to reduce Public stressing and prevent further long term surface water contamination of the PripyatFood product, milk water external inhalation
Actual dose
Public perception about
Dose realization (%) during a 70 years for children born in 1986
From I. Los, O. Voitsekhovych, 2001
For 1-st year about 47 %
For 10 years about 80%
Years
Inadequate Radiation Risk Perception by Public was a key Inadequate Radiation Risk Perception by Public was a key reason in reason in WATER PROTECTION ACTION PLANWATER PROTECTION ACTION PLAN implementing implementing
During initial period after the Chernobyl During initial period after the Chernobyl Accident the number of expensive Accident the number of expensive actions to reduce secondary actions to reduce secondary contamination of the rivers and contamination of the rivers and groundwater have been applied. groundwater have been applied.
Most of the actions were extremely Most of the actions were extremely expensive and ineffective.expensive and ineffective.
extra slides for questions
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
(Shaw et al., 2002)
From Chernobyl to Fukushima: introduction
(IAEA, 2006)
The aquatic ecosystem radioactive contamination story, The aquatic ecosystem radioactive contamination story, natural attenuation process and assessment for natural attenuation process and assessment for
effectiveness of the water protectioneffectiveness of the water protection
Y.Onishi, O.Voitsekhovych, M.Zheleznyak
Chernobyl What Have we learned. The Successes and Failures to Mitigate Water Contamination over 20 years.
