Towards a protection of species at the population level: derivation of PNEDR values by modelling population responses to ionizing radiations Emilie Lance,

Towards a protection of species at the population level: derivation of PNEDR values by

modelling population responses to ionizing radiations

Emilie Lance, Frédéric Alonzo, Jacqueline Garnier-Laplace

Direction de l’Environnement et de l’InterventionService d’Etude du Comportement des Radionucléides dans les EcosystèmesLaboratoire de Modélisation Environnementale

EMRAS Meeting, 26-27/01/2010, Vienna, Austria

- Titre Partie/Dir/Service – Page 2

Evaluation of environmental risk from ionizing radiations

IAEA : standards for environmental radioprotection

ICRP : recommendation of similar method than for chemical substances, 2005 Sept

Background on ERICA and PROTECT: recommendation

FASSET (2001-2004) 5th PCRD

ERICA (2004-2007) 6th PCRD

PROTECT (2006-2008) 6th PCRD

European projects:

Risk assessment screening dose or dose rate, « benchmarks » for the protection of wild species againts impact of ionizing radiations.

EMRAS Meeting, 2010-01-26/27, Vienna, Austria


FREDERICA database : effects of ionizing radiations on non-human organisms

• Ecotoxicity data

• 25000 couples (dose or dose rate, effect) from 1040 references

• 16 pseudo-taxonomic groups

• 3 ecosystems

Vertebrates

Invertebrates

Primary producers

Ecosystems

terrestrial

freshwater

marine

Biologicalcomplexity

Background on ERICA and PROTECT: data set



Effects observed at the individual and sub-individual level

Which data for the derivation of benchmarks ?

On the first hand, data on chronic exposure to gamma radiation, external radiation exposure (µGy.h-1)

4 categories: - (1) morbidity: growth rate, immune system, behavior (impact on the central nervous system),

- (2) mortality: also mutations that affect life expectancy

- (3) reproductive capacity: fertility, fecundity, hatching/survival of embryos…

- (4) mutations of somatic and reproductive cells

Background on ERICA and PROTECT: data set



Radiotoxicity data relative to life-history traits (protection of the population)

Dose (rate)-effect relationships: critical data, EDR10 (dose rate inducing 10% of effect on the endpoint in comparison with controls)

For a given species, if an EDR10 is available for several endpoints, the most sensitive is selected

Derivation of criteria for the protection of populations

Effect (%)

Dose (Gy)Dose rate (µGy/h)

ED10EDR10

ED50EDR50

10

Regression modelExperimental data

Background on ERICA and PROTECT: method



Background on ERICA and PROTECT: method

Extrapolation model « Species Sensitivity Distribution » (SSD)

HDR5 = Dose rate protecting 95% of species (95% are affected at maximum 10% of effect in comparison with controls)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 10 100 1000 10000 100000 1000000

Dose Rate (µGy/h)

Percentage of AffectedFraction

Best-Estimate Centile 5% Centile 95%

Vertebrates Plants Invertebrates

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 10 100 1000 10000 100000 1000000

Dose Rate (µGy/h)






5%

HDR5

Garnier-Laplace et al. (2008)

HDR5 / safety factor = PNEDR (Predicted No Effect Dose Rate)

Derivation of criteria for the protection of populations



Background on ERICA and PROTECT: possible improvements

Biochemical level

Whole organism level

Physiological level

Population level

Community level

Ecosystem level

Time scale

Life-history traits: survival, growth, fecundity

Sensitivity of the population growth rate to impact on individuals endpoints

Life history strategies

dynamics

impact

Hypothesis: the toxicity at the individual level is comparable between species and endpoints

Ecotoxicity data at the individual level



age

Abundance

time

1) Population structured per age classes

2) Cohorts vary over time depending on survival and fecundity

12 3…

iagemax

Ni+1 = Pi Ni

at time t + 1

iN1 = Fi Ni

Ni

at time t

Eggs, juveniles(future cohort N1)

Modeling population size in number Determination of population growth rate

Population dynamic depending on survival and reproduction in each life stage

Fecundity rate Fi

Survival rate Pidepending on age i




Reduction in survival

Reduction in fecundity

Delay in reproduction0.0

1.0

2.0

3.0

0% 20% 40% 60% 80%

Individual level effect

0.0

1.0

2.0

3.0

0% 20% 40% 60% 80%

Dela

y in

pop

ula

tion

gro

wth

(rela

tive t

o g

en

era

tion

tim

e T

)

T = 10 days T = 12 weeks

Sensitivity of population depends on individual endpoints

Sensitivity of population depends on life history strategy of different species

Comparison of population sensitivity to changes in different endpoints and different species

Eisenia fetidatoxicité chronique de radiations gamma externes (Co-60)

Daphnia magnatoxicité chronique de U et Am-241 dissous et radiations gamma externes (Cs-137) Alonzo et al., 2008




Simulation of population dynamics of each species in control conditions and with 0 to 100% decrease in each life-history trait

Method and required data: a first theoretical step

Toward a protection of species at the population level

Hypothesis of the modelEnclosed systemNo density-dependenceOptimum environnemental conditions

Relative sensitivity of the population to different individual endpoints for a species

Population dynamic

0 15 6030 45

25000

50000

0

75000

100000

time (days)ta

ille

de p

op

ula

tion

To understand and compare life-history strategies between different species

• age sexual maturity • survival at each stage• fecundity at each stage(number of eggs, hatching %, juveniles survival…)

Bibliography

modélisation

Pop-EDR10: Dose rate inducing 10% decrease in population growth rate

Dose rate (µGy/h)ED10

EDR10

10

Effect (%)

%

Dose rate ?

-10% on thepopulation growth rate

2nd step: utilization of data from FREDERICA



0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 10 100 1000 10000 100000 1000000

Dose Rate (µGy/h)




0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1 10 100 1000 10000 100000 1000000

Dose Rate (µGy/h)






5%

HDR5

Derivation of benchmarks

Extrapolation model « Species Sensitivity Distribution » (SSD) with pop-EDR10 = at the population level

New HDR5 = Dose rate protecting population dynamics for 95% of species (decrease in population growth rate of less than 10% in comparison with controls)

Pop-EDR10

Toward a protection of species at the population level



Thanks for your attention

// more informations on…

European program ERICARisques des substances radioactives pour l’environnementhttp://www.erica-project.org

European program PROTECTProtection of the environment from ionising radiation in a regulatory context http://www.ceh.ac.uk/protect/

FREDERICA Radiation Effects Database http://87.84.223.229/fred/mainpage.asp

http://www.irsn.org/CIPR http://www.icrp.orgNEA http://www.nea.fr


Towards a protection of species at the population level: derivation of PNEDR values by modelling population responses to ionizing radiations Emilie Lance,

Documents

edr10 dose rate

austria slide

titre partiedirservice

couples dose

data set emras meeting

protection of species

method emras meeting

critical data