Time changes in radiocesium concentration in aquatic ...Yuichi Onda, Keisuke Taniguchi, Hiroaki...
Transcript of Time changes in radiocesium concentration in aquatic ...Yuichi Onda, Keisuke Taniguchi, Hiroaki...
Yuichi Onda, Keisuke Taniguchi, Hiroaki Kato, Kazuya
Yoshimura, Yoshifumi Wakiyama, Sho Iwagami, Maki
Tsujimura, Aya Sakaguchi
Center for Research in Isotopes and Environmental Dynamics
University of Tsukuba
Masatoshi Yamamoto LLRL, Kanazawa University
Time changes in radiocesium
concentration in aquatic systems
affected by the Fukushima Daiichi
NPP accident
,
Mapping of radio-Cs
2 km mesh in Fukushima pref.
・Sampling participants: more than 1000 people
・Sampling points: about 2200
・Sample numbers: about 11000
・Sampling area: in 80 km from Fukushima-daiich NPP
・Cooperative institutes and companies:
94 universities (hospitals), 14 companies
・ Analytical institutes: 20
・Sampling :
First campaign : 6th/June – 14th/June
Second campaign : 27th/June – 8th/July
Thank you for the IAEA’ s support!(protocol, standard material etc)
Time Change of Cs-137 concentration in water in Ukraine C
s-137 c
on
cen
trati
on
in
wate
r
[Bq
/m3]
k1
k2
k3
after Smith et al, (2005 )
)()()()()( 321 tktktk
cR eeeDtC
First flush
Fixation?
Downward migration?
Fukushima 2011 2014
June 2011- 2014 (funded by MEXT, NRA)
Yamakiya area
Pasture A plot
Cropland B1, B2
plot Cropland A1, A2
plot
Paddy field (scraped, control)
Kotaishi catchment
Iboishi
catchment
Pasture B plot
Ishidaira
Cathment Pasture C plot
Yamakiya Study site Cs transfer from forested area
Sediment and Cs yield from various land
use
Young cedar
Mature cedar
Broadleaf
Cs transfer in forest
Young cedar plot
河川
都市域
水田
草地
畑地
森林
流域界
Forest
Cropland
Grassland
Paddy
field
City
River
Kuchibuto
upstream
Mizusakai
River monitoring sites
Bare land Cultivated (gentle)
Forest (young ceder)
Soil Erosion Plots
Grass land Cultivated (Steep)
Pasture A Pasture B
Parshall flume
and water gage
↑turbidimeter・
SS sampler
Striped surface soil
(5-10cm)↓
Non-striped
surface soil
Migration with cultivation Migration of radionuclides from paddy field to river (and plant) by rice cultivation.
Migration form soil to rice plant
SS sampler
Observation of suspended sediment discharge from paddy field by puddling
11
Young cedar Mature cedar Broadleaf
(Beech and Red pine)
Experimental site
Mature cedar
1200/ha
Young cedar
3300/ha Broadleaf
2500/ha
Stemflow collector
Throughfall collector
Filtering water by 100μm stainless mesh.
Water samples Litter samples
Leaves, twig, branch, bark were manually separated.
(a) Mature cedar
Cumulative Cs-137 deposition (Bq m-2) onto forest floor
TF
LF
SF
TF
LF
SF
TF
LF
SF
(b) Young cedar (c) Broad-leaved Jan. 2012
Oct. 2011
Apr. 2012
Aug. 2012
Nov. 2012
Jan. 2012
Oct. 2011
Apr. 2012
Aug. 2012
Nov. 2012
Jan. 2012
Oct. 2011
Apr. 2012
Aug. 2012
Nov. 2012
Throughfall + Litterfall input
200 days after the NPP accident JER (under review)
Time series of dissolved 137Cs concentration in stream water at Iboishiyama and time series of dissolved 137Cs
concentration in groundwater at Iboishiyama with exponential approximate line.
Stream water
-30 m GW
-5 m GW
-15 m GW
C(t) = 1.181e-0.011t+0.114e-0.001t
C(t) = 0.012e-0.004t
C(t) = 0.023e-0.003t
C(t) = 0.002e-0.0004t
200 days!
Throughfall!
JER (in press)
Headwater catchment
Groundwater
Bare land Cultivated (gentle)
Forest (young ceder)
Soil Erosion Plots
Grass land Cultivated (Steep)
Pasture A Pasture B
Temporal change in normalized cesium-137 concentration in sediment discharge from each plot. Each point
Scuncultivated(t) = 0.0619 exp(-0.196t) Sccultivated = 0.0137 (Averaged value of the 2 plots (A2,B2)
Scgrassland = 0.0134 (average value of grassland A,B,C)
Normalized Cs-137 cocentration (Sc): 137Cs concentration per unit deposition density
0.001
0.01
0.1
1
0 1 2 3 4
No
rma
liz
ed
co
ce
ntr
ati
on
Sc
(B
q k
g-1
)/(B
q m
-2)
Time after the FDNPP accident (year)
福島県内固定観測点によるSc
代掻き時調査に基づくSc
Scpaddy(t) = 1.62e -10.1t + 0.145e-0.958t Scforest(t) = 0.074e -0.327 t
Normalized Cs-137 Concentration (Sc)
Paddy field Sc(t) Forest catchments Sc(t)
Experimental paddy
Fukushima paddling data Ishidaira site
18
Radionuclide migration to rivers and ocean (initial 6 sites)
19
From 10 August 2011 to 11 May 2012 The total flux
of radiocesium into the Pacific Ocean estimated
was corresponding to 1.13%of the total estimated
radiocesium fallout over the basin catchment.
River monitoring sites
1. Longer-term Abukuma sites (n = 6):
– Established from June 2011
2. New sites (n = 24):
– Abukuma Basin and small coastal catchments
– Established in October-December 2012
• Catchment areas range from 7.6 – 5,170 km2
• Average inventories based on MEXT
• Cs-137: 19-2380 kBq m-2
Kuchibuto upstream
Kuchibuto down
Iwanuma
Fushiguro
Mizusakai Kuchibuto Middle
河川
都市域
水田
草地
畑地
森林
流域界
Forest
Cropland
Grassland
Paddy field
City
River
Landuses in Abukuma catchments and 6 long-term sites
Time change of suspended sediment concentration in 6 long-term sites
1000
10000
100000
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00
Susp
en
de
d s
ed
ime
nt
Cs-
13
7 c
on
cen
trat
ion
[B
q/k
g]
Year after the accident
水境川
口太川上流
口太川中流
口太川下流
伏黒
岩沼
tributary
mainstream
Abukuma main
stream
Kuchibuto
river(tributary)
Mizusakai Kuchibuto upstream Kuchibuto middle stream Kuchibuto Downstream Fukushiro (abukuma) Iwanuma (abukuma)
upstream
downstream
forest
Paddy field Urban
Time change of Suspended sediment Cs-137 concentration for 30 sites
0.001
0.01
0.1
1
0 0.5 1 1.5 2 2.5 3 3.5 4
Abukuma mainstream
0.001
0.01
0.1
1
0 0.5 1 1.5 2 2.5 3 3.5 4
Coastal catchment
0.001
0.01
0.1
1
0 0.5 1 1.5 2 2.5 3 3.5 4
Abukuma East Tributaries
No
rmar
ized
Cs-
13
7 C
on
cen
trat
ion
[B
q k
g-1
/B
q m
-2]
0.001
0.01
0.1
1
0 0.5 1 1.5 2 2.5 3 3.5 4
Abukuma West tributaries
Years after Fukushima NPP accidents
USLE-based soil erosion calculation (25m-grid)
NDVI高 : 8421
低 : 20
0̄ 10 205km
土地利用
水田
畑(耕作)
畑( 未耕作)
草地
裸地
常緑樹針葉樹
常緑針葉樹( マツ)
常緑広葉樹
落葉広葉樹
落葉針葉樹
都市
住宅
水域
湿原
そのほか
0̄ 10 205km
傾斜 (度)
40
0
0̄ 10 205km
(a) (b)
(c) (d)
Slope(S)
Vegetation factor (C)
Landuse
K factor
Calculation: 1 month step Input parameters ; Rainfall (Thiessen-based), Sc (t) of each land use :paddy:using the monthly discharge data Wakahara et al. 2014)
(a)平成23年3月11日~10月31日
kBq/m2
- 0.1
0.1 - 0.5
0.5 - 1
1 - 5
5 -10
10 -
¯0 10 205
km
kBq/m2
- 0.1
0.1 - 0.5
0.5 - 1
1 - 5
5 -10
10 -
¯0 10 205
km
kBq/m2
- 0.1
0.1 - 0.5
0.5 - 1
1 - 5
5 -10
10 -
¯0 10 205
km
(b)平成23年11月1日~平成24年10月31日
(c)平成24年11月1日~平成25年10月31日
Calculated Cs-137 migration
Calculation has been conducted 1 month step Input parameter ;Rainfall (Thiessen-based), Sc (t) of each land use :paddy:using the monthly discharge data by Wakahara et al. 2014)
a) Mar.31, 2011-Oct.31, 2011
b) Nov. 1, 2011-Oct.31, 2012
b) Nov. 1, 2012-Oct.31, 2013
Sediement source estimates by USLE-based model
No
rmal
ized
Cs-
13
7C
oce
ntr
atio
n (
Bq
/kg)
/(B
q/m
2)
Years after FDNPP accident
Mizusakai Kuchibuto upstream
Kuchibuto Middle stream
Kuchibuto downstream
Fushiguro (mainstream)
Iwanuma (mainstream)
Time Changes of the Model calculation and measured value for 6 long-term monitoring sites
measured
calculated
measured
calculated
measured
calculated
measured
calculated
measured
calculated
measured
calculated
Conclusion
Based on intensive field monitoring from June 2011-
present reveal that the time change of Cs-137 differ
between land uses.
Downstream Suspended sediment concentration
differs between places in by 30 locations of river
monitoring data.
For accurate modelling after Nuclear Emergency,
detailed field monitoring is the most important !