transfer study of c and h between air, grass and cows ...€¦ · – emras ii, wg7, january 2010...

– EMRAS II, WG7, January 2010 –

TRANSFER STUDY OF 14C and 3H BETWEEN AIR, GRASS AND COWS : VALIDATION OF

TOCATTA MODEL (VATO)

IRSN / DEI / SECRE (France)

Denis MARO 1

Séverine Le Dizès 2 & Didier Hébert 1

1IRSN/Laboratory of Continental Radioecology/Cherbou rg-Octeville2IRSN/DEI/Environmental Modelling Laboratory/Cadarac he, St-Paul-lez

Durance


Context and objectives | Methodology | Results | Conclusion

� Uncertainties in transfer models of 14C and 3H in rural environment in case of accidental release due to a lack of global experimental data

� In general transfer models are based on constant isotopic ratio and this concept is not very appropriate with accidental releases

Necessary to acquire well-documented new data of concentrations of 14C and 3H in different compartments of the rural environment

Context


� Estimate fluxes of 14C and 3H in a grassland ecosystem (Raygrass), in relation with : - 14C and 3H concentrations in air,- Climate conditions,- Land use (grazing, silage maize and hay).

� Study transfers of 14C and 3H to cows and milk in function of the alimentary diet.

In order to improve the TOCATTA model or another model

Objectives



� Originality : Using the atmospheric release of radionuclidesof AREVA NC La Hague reprocessing plant to quantify the transfers of 14C and 3H in rural environment

Two chimneys



14C and 3H atmospheric releases

0,0E+00

1,0E+13

2,0E+13

3,0E+13

2003 2004 2005 2006 2007

Time (years)

3H (Bq.an-1)

0,0E+00

1,0E+12

2,0E+12

3,0E+12

14C (Bq.an-1)

Tritium

Carbon 14

Lead to greater concentration than the background level in the environment



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#BEAUMONT-HAGUE

SAINT-GERMAIN-DES-VAUX

AUDERVILLE

DIGULLEVILLE

OMONVILLE-LA-ROGUE

OMONVILLE-LA-PETITE

JOBOURG

ECULLEVILLE

GREVILLE-HAGUE

HERQUEVILLE

6.3

5.5

5.4

4.8

5.5

5.2

7.9

6.6

6.1

5.2

6.9

8.7

8.5

7.7

4.3 8.0

5.2

5.9

9.1

9.0

9.2

3.1

4.4

5.9

9.4

8.0

9.2

9.9

8.3

3.9

7.5

5.1

6.0

7.9

7.0

5.5

6.9

10.3

13.2

15.2

54.6

10.9

14.0

12.5

12.9

11.4

12.8

13.1

14.4

12.5

10.7

13.2

14.4

12.3

11.1

10.2

COGEMA-ANDRA

N

EO

S

500 0 500 1000 M

Example of OBT concentration measured in furze

AREVA NC

0

5

10

15

20

25

30

35

40

1975 1980 1985 1990 1995 2000 2005

Date (year)

concentration (Bq.L

-1)

Background noise



Wind conditions 2008 - "Omonville La Petite". Wind speed (m.s-1) and Direction (°)

« Atelier Nord » : a well located experimental site, considering the most frequent wind direction

EXPERIMENTAL SITE« Ateli er Nord »

AREVA LA HAGUE

Site location

0

2

4

6

8

10

12

360

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340



Experimental design (sampling periodicity 1 month)

Continuously Recording Field Monitor for Krypton-85

10 m mast with sonic anemometer (turbulence)

Weather station

LabMeteorological data acquisition

CO2 measurement acquisition (LICOR 7000)

Farm

Grass (Raygrass)

14C trapping device (bubble gas through soda)



350

400

450

500

550

600

650

700

750

01/04/2007 06/04/2007 11/04/2007 16/04/2007 21/04/2007 26/04/2007

Date

Con

cent

ratio

n (p

pm)


Example of CO2 atmospheric concentrations



Example of 14C concentrations

Does the model give a good representation of 14CO2 between air and grass? No, as it uses constant isotopic ratio (no photosynthetic process)To get a better model-measures comparison : need to rebuild 14Catmospheric concentrations on an hourly basis and use a dynamic model

0

200

400

600

800

1000

1200

1400

01/08/2006 17/02/2007 05/09/2007 23/03/2008 09/10/2008 27/04/2009

Date

Con

cent

ratio

n (B

q.kg

-1 C

)

Air Grass zone 1 Grass zone 2 HayGrass from Frênes Soil zone 1 Soil zone 2 Soil from Frênes

Cow studyGrassland study



Krypton 85 : a plume tracer measured with shortperiodicity (1 minute) compared with 14C (1 month)

0,0E+00

2,0E+09

4,0E+09

6,0E+09

8,0E+09

1,0E+10

1,2E+10

1,4E+10

1,6E+10

1,8E+10

2,0E+10

08:40 08:55 09:10 09:25 09:40 09:55 10:10 10:25 10:40 10:55 11:10 11:25 11:40 11:55

Time

UP

3 (B

q.s-1

)

0,0E+00

5,0E+04

1,0E+05

1,5E+05

2,0E+05

2,5E+05

85K

r co

ncen

tratio

n (B

q.m

-3)Emission

Environmentalmeasurements


Need to rebuild hourly 14Catmospheric concentration with hourly 85Kr concentration and

monthly 14C concentration

0,0E+00

1,0E+04

2,0E+04

3,0E+04

4,0E+04

5,0E+04

6,0E+04

7,0E+04

8,0E+04

9,0E+04

1,0E+05

01/10/06 06/10/06 11/10/06 16/10/06 21/10/06 26/10/06

Date

Concentration (Bq.m

-3)

Krypton 85 : a good indicator of 14C atmosphericdispersion over a short periodicity

0,0E+00

5,0E+03

1,0E+04

1,5E+04

2,0E+04

2,5E+04

3,0E+04

01/10/06 06/10/06 11/10/06 16/10/06 21/10/06 26/10/06

Date

Concentration (Bq.kgC-1)


To obtain more precise 14C atmospheric concentrations for calculations


Conclusion

� The results analysis needs dynamic modelling of 14C and 3H in plants, it’s necessary to take into account the modelling of photosynthesis

� Concerning 3H modelling in case of accidental release, it is also necessary to consider water transfer processes with a dynamic approach based on a short time step

� Ongoing discussions with INRA (Clermont-Ferrand) to use the PASIM* model

� PASIM* is a biogeochemical grassland ecosystem model that simulates fluxes of C, N, water and energy at the soil-plant atmosphere interface with hourly step time

*Riédo et a., 1998. A Pasture Simulation Model for dry matter production, and fluxed of carbon, nitrogen, water and energy. Ecol. Model. 105, 141-183.



Agenda

Carbon 14

2007-2009 : Transfers between air, grass and soil

Tritium

2010 : Measurement (speciation of 3H releases in air)

2009-2010 : Transfers to cow

2009-2010 : Model-measures comparisons

2010/2011 : Publication

2010-2011 : Transfers between air, rain water, grass and soil…dry and wet deposition

2012 : Transfers to cow

2012 : Publication

2011-2012 : Model-measures comparison



Thank-You

transfer study of c and h between air, grass and cows ...€¦ · – emras ii, wg7, january 2010...

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