Radioecological sensitivity of the coastal marine regions...1994; IAEA-TECDOC-1330, 2003, Iosjpe et...

Radioecological sensitivity of the coastal marine regions

Norwegian Radiation Protection Authority

ICRER 2011, 19-24 June 2011 Hamilton Canada

M. Iosjpe

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Environmental sensitivity of the marine regions

EMRAS II ProgrammeEnvironmental sensitivity working group

The environmental sensitivity has been considered as a dose to adults

Release scenario:

a single deposition of 1000 Bq/m2 of radionuclides in each marine region


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NRPA box model: schematic structure of the processes involved in modelling

Surface water

Deep water

Surface sediment

Deep sediment

Advection

Advection

Advection

Sedimentation

Sedimentation

Resuspension

Bioturbation Pore water diffusion

Burial

Radioactive decay

Radioactive decay

Radioactive decay

Seaweeds Fish Molluscs Crustacea

CFS CFF CFM

CFC

Doses to man and biota

Ice module

Freezing and melting processes

Middepth water

Advection

Advection

Bacteria Mammal DCF

Comparison of the contribution toindividual dose to man from seafoodingestion and external exposureindicates a clear domination of theingestion pathway (MARINA-Med EC,1994; IAEA-TECDOC-1330, 2003,Iosjpe et al., 2009)


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NRPA box model: equations of the transfer of radionuclides between the boxes (Iosjpe et al., 2009)

iiiiiij

n

jijjji

n

jji

i TtQAkATtkATtkdtdA

,)()(11

( ),,t T

TTi

i

i

10

t t

T wi v v M jkj km i i

min

( , ) , 0

Ai = 0, t < Ti

Non-nstantaneous mixing in oceanic space


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Model Corroboration (Iosjpe, 2006; Iosjpe et al., 2009 )

Years

1940 1950 1960 1970 1980 1990 2000 2010

Con

cent

ratio

n in

sed

imen

t, B

q/kg

, d.w

.

0

200

400

600

800

1000

1200

1400

1600

1800

EstimatedMeasured (Average)

Years

1940 1950 1960 1970 1980 1990 2000 2010

Con

cent

ratio

n of

239 Pu

in s

edim

ent,

Bq/

kg, d

.w.

0

5

10

15

20

25

30

35

Years

1988 1990 1992 1994 1996 1998 2000 2002

99Tc

wat

er c

once

ntra

tion,

Bq

m-3

10

100

1000

10000

NRPA, 2002, 2006Average concentrationMinimal concentrationMaximal concentrationPresent version

Cumbrian Waters

Pu-239 Tc-99


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IAEA, 2004: sediment distribution coefficients Kd, andconcentration factors for fish (CFf), crustaceans (CFc),molluscs (CFm) and seaweeds (CFs)

137Cs 90Sr 131I 239Pu Kd 4000 8 70 100000 CFf 100 3 9 100 CFc 50 5 3 200 CFm 60 10 10 3000 CFs 50 10 10000 4000

Selected radionuclides


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Selected marine regions

CW

LB

NC

OB

S

GR

Cumbrian waters of the Irish Sea (CW)

Lyme Bay on the English Channel (LB)

North Sea of the Norwegian coasts (NC)

Skagerrak (S)

Gulf of Riga on the Baltic Sea (GR)

Ob Bay on the Kara Sea (OB)


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Name Volume, m3 Depth, m Surface area, m2

Irish Sea: Cumbrian Waters 3,80E+10 2,80E+01 1,36E+09

English Channel: Lyme Bay 2,01E+11 3,95E+01 5,09E+09

North Sea: Norwegian Current Surface 9,20E+12 1,56E+02 5,90E+10

Skagerrak 6,78E+12 2,10E+02 3,23E+10

Baltic Sea: Gulf of Riga 4,05E+11 2,30E+01 1,76E+10

Kara Sea: Ob Bay 3,19E+11 1,10E+01 2,90E+10

Selected marine regions


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Selected marine regions: SSL (suspended sediment load) and SR (the mass sedimentation rate)

Name SSL t/m3 SR, t/m2/y Irish Sea: Cumbrian Waters 1,0E-05 6,0E-03 English Channel: Lyme Bay 3,0E-06 1,0E-04 North Sea: Norwegian Current Surface 6,6E-06 1,0E-04 Skagerrak 1,0E-06 5,0E-03 Baltic Sea: Gulf of Riga 1,0E-06 5,0E-04 Kara Sea: Ob Bay 5,0E-05 1,0E-03

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Seafood consumption (Smith & Jones, 2003) corresponds to results for the population of the coastal regions

Group 1 (adult) Group 2 (child) Group 3 (infant) Fish 51 10.2 2.5 Crustacean 17 2.25 0 Molluscs 14 3.5 0 Seaweeds 5 0 0


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Years

0,0 0,2 0,4 0,6 0,8 1,0 1,20,01

0,1

1

10

100Cs-137, Fish, OB Sr-90, cructaceans, S I-131, seaweeds, LBPu-239, molluscs, CW

Concentration of radionuclides in seafood, Bq/kg w.w.

CW

LB

NC

OB

S

GR

Radionuclides concentration in seafood


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Dose (Sv) for different age from 137Cs (Cumbrian Waters), and during different times from 239Pu for adult (Skagerrak).

137Cs Cumbrian Waters

Adult 10 y 1 y

Sv

0,0

2,0e-7

4,0e-7

6,0e-7

8,0e-7

1,0e-6

1,2e-6

1,4e-6

1,6e-6

1,8e-6

239PuSkagerrak

1st year 2nd year 10th year

Sv

0

1e-5

2e-5

3e-5

4e-5

5e-5


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131I

Fish Crustaceans Molluscs Seaweeds

Sv

1e-9

1e-8

1e-7

1e-6

1e-5

137Cs


Sv

0,0

2,0e-7

4,0e-7

6,0e-7

8,0e-7

1,0e-6

1,2e-6

1,4e-6

90Sr


Sv

0,0

2,0e-8

4,0e-8

6,0e-8

8,0e-8

1,0e-7

1,2e-7 239Pu

Fish Crusaceans Molluscs Seaweeds

Sv

0

5e-6

1e-5

2e-5

2e-5

3e-5

3e-5

Doses (Sv) from one year of consumption of I-131, Cs-137, Sr-90, and Pu-239 in fish, crustaceans, molluscs, and seaweed.

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Doses, Sv

0,0E+005,0E-07

1,0E-06

1,5E-06

2,0E-06

2,5E-06

3,0E-06

CW LB NC S GR OB

Cs-137

0E+00

1E-07

2E-07

3E-07

4E-07

5E-07

CW LB NC S GR OB

Sr-90

0E+00

2E-06

4E-06

6E-06

8E-06

1E-05

CW LB NC S GR OB

I-131

0E+00

2E-05

4E-05

6E-05

8E-05

1E-04

CW LB NC S GR OB

Pu-239


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Potential improvement: comparison of scenarios: releases in the local environments

0,0E+005,0E-071,0E-061,5E-062,0E-062,5E-063,0E-06

CW LB NC S GR OB

Cs-137

0,00E+00

2,00E-06

4,00E-06

6,00E-06

8,00E-06

1,00E-05

1,20E-05

CW LB NC S GR OB

I-131

0,00E+00

1,00E-07

2,00E-07

3,00E-07

4,00E-07

5,00E-07

6,00E-07

CW LB NC S GR OB

Sr-90

0,00E+00

2,00E-05

4,00E-05

6,00E-05

8,00E-05

1,00E-04

CW LB NC S GR OB

Pu-239


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Potential improvement: IMPACT OF ASSUMPTIONS ABOUT SEAFOOD CONSUMPTION

0,0E+00

5,0E-07

1,0E-06

1,5E-06

2,0E-06

CW NC

Cs-137

The green color corresponds to the results of dose calculations from Cs-137 release, where the same assumptions about the levels of seafood consumption for the population of the coastal regions, provided by Smith & Jones, (2003) have been used in all marine locations, while the red color corresponds to calculations where site specific information about average seafood consumption, provided by Smith & Jones, (2003) and by Bergsten (2003) have been used for the Cumbrian waters (CW) and for the Norwegian coastal waters (NC), respectively.

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PARAMETERS AND PROCESSES CONTROLLING THE VULNERABILITY OF THE MARINE REGIONS

)S(

0

0

P

)S()L(

VP

dPdV)P(S

0

The local sensitivity indexV(S) and P correspond to state variables (for example, doses to man) and parameters which are under evaluation; P0 and V0(S) correspond to the basic values of the parameter P and the state variable V(S). In the present paper the values for P0and V0(S) correspond to results provided by

PARAMETERSfl - maximum water exchange for the compartment SR - sedimentation rate SSL - suspended sediment load in water column RW - sediment reworking rateRT - pore-water turnover rate Kd - sediment distribution coefficient D - molecular diffusion coefficient CF - radionuclide concentration factors for seafood

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Results• Doses to adults for all selected radionuclides and marine

locations have low sensitivity to the molecular diffusion coefficient (D) and pore-water turnover rate (RT).

• Sr-90: sensitivity index is low for parameters describing water-sediment interactions

• I-131: only one parameter, namely the concentration factor for seaweeds, has a high sensitivity index value

• Doses to man are most sensitive to the process of bioaccumulation (parameter CF)

• Doses to man are sensitive to the process of the particle mixing (parameters Kd, Rw, SSL), but only for the radionuclides with relatively high sediment distribution coefficient (Pu-239, Cs-137)


Board # 048 Abs # 746

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Absolute values of the local sensitivity index for the advection rates (fl).

Locations OB CW LB S GR NC 137Cs 0.26 0.10 0.06 0.21 0.10 0.22 90Sr 0.39 0.16 0.06 0.21 0.13 0.23 239Pu 0.11 0.02 0.04 0.12 0.00 0.15

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Absolute values of the local sensitivity index for sediment reworking rate (RW), sediment distribution coefficient (Kd), suspended sediment load in water column (SSL), sedimentation rate (SR).

OB CW LB S GR NC 137Cs Rw 0.19 0.11 0.06 0.08 0.17 0.07 239Pu Rw 0.33 0.23 0.39 0.28 0.33 0.18 137Cs Kd 0.21 0.22 0.06 0.09 0.21 0.07 239Pu Kd 0.07 0.27 0.36 0.20 0.37 0.13 239Pu SSL 0.39 0.13 0.04 0.04 0.04 0.00 239Pu SR 0.11 0.16 0.01 0.29 0.06 0.00

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Absolute values of the local sensitivity index for concentration factors for fish (CFf), crustaceans (CFc), molluscs (CFm) and seaweeds (CFs).

137Cs 90Sr 131I 239Pu CFf 0.72 0.36 0.01 0.07 CFc 0.12 0.20 0.00 0.05 CFm 0.12 0.33 0.00 0.60 CFs 0.04 0.12 0.99 0.28

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Potential improvement: evaluation of the key environmental parameters (Poster, ICRER2011 –sensitivity analysis of the model parameters, f. ex., CF, Kd, … )

)SSLk1(dhR

)SSLk1(hdD

)SSLk1(dkSR

kd

ST

dSd

dWS

)SSLk1(d

)1(kR

d

dW

)]1(k[h

)1(kR)1(k

R)]1(k[h

DkdS

dW

d

T

d2S

SW

)]1(k[hSRk

)]1(k[hDk

dS

d

d2S

SM

)]1(k[hhDk

dSMSMS

)]1(k[hSRkk

dSM

dMD

.

Water column

Surface sediment

Middle sediment

Deep sediment

kWS

kWS

kSM

kMS

kMD

Water-sediment interaction


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Definition of parameters is not a trivial task: concentrations (Iosjpe, 2011)

Years

0 1 2 3 4 5

238 Pu

con

cent

ratio

n in

wat

er a

nd s

edim

ent

1e-5

1e-4

1e-3

1e-2

1e-1

1e+0

1e+1

(A) surface water(B) surface water(A) bottom water (B) bottom water(A) surface sediment(B) surface sediment

Pu-238 bulk concentrations in surface water, bottom water and sediment compartments: (A) the basic scenario; (B) Kdincreased by a factor of 5, Rw decreased by a factor of 5, in comparison to (A). Results correspond to the southern part of the Norwegian Current.


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Years

0 20 40 60 80 100

238 Pu

bul

k co

ncen

trat

ion

in s

urfa

cese

dim

ent

1

10

Variant (A)Variant (B)

40 years

69 years

Practical results: half-life in sediment (Iosjpe, 2011)


Radioecological sensitivity of the coastal marine regions...1994; IAEA-TECDOC-1330, 2003, Iosjpe et...

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