IAEAInternational Atomic Energy Agency

WG5: Exposure and Effects to Biota

Jordi Vives i BatlleNick Beresford

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Aims and Objectives

• Demonstrate fit for purpose regulatory models• Validate, test, improve models for different

applications• Good practice guidance

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Model-Model• Inter-comparison of models to estimate radionuclide activity

concentrations in non-human biota.• Inter-comparison of absorbed dose rates for non-human biota.• The estimation of absorbed dose rates for non-human biota: an

extended intercomparison.• Inter-comparison of dynamic models for radionuclide transfer to

marine biota in a Fukushima accident scenario.

Exposure - outputs

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……outputs

Model-Data• Predicting exposure of wildlife in radionuclide contaminated

wetland ecosystems.• Assessing doses to terrestrial wildlife at a radioactive waste

disposal site: inter-comparison of modelling approaches. • Predicting the radiation exposure of terrestrial wildlife in the

Chernobyl exclusion zone: an international comparison of approaches.

• An International model validation exercise on radionuclide transfer and doses to freshwater biota.

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……outputs

Other• Should we ignore U-235 series contribution to dose?• Radionuclide biological half-life values for terrestrial and aquatic

wildlife• Radiological dose rates to marine fish from the Fukushima

Daiichi accident: the first three years across the north Pacific• A comparison of the ellipsoidal and voxelized dosimetric

methodologies for internal, heterogeneous radionuclide sources

……. and more ……

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Exposure – this week

• New modelling approaches• New databases• Analyses of MODARIA I outputs• New datasets

• Links to WG1

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Agreed activites

Spatial modelling• Animal-environment interaction

modelling started in MODARIA

Estimating soil contamination in home ranges of different species

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Moose - scenario

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ECOSPACE

Moose - scenario

Complete by mid-term

Summer

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Reindeer - scenario

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MODARIA I Biological half-life database

• Improve model parameters and reduce uncertainty (initial focus marine)

• Expand allometric approaches?

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‘Lessons learnt’ paper

• Capabilities of openly available models• How you ‘make’ model do what you need• Parameter values• Dosimetry/voxels/geometries - organisms• Coping with heterogeneous media distributions• Radionuclide specific issues (decay series, Ar, Kr

etc.)• How to sample/analyse for wildlife assessment • Extending allometric capabilities

Complete by mid-term

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Collaboration with WG1

Providing expertise in non-human assessment modelling (running models in scenarios)

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Other activities

• Analyses of Wildlife Transfer Database• Arctic data

• Model testing• Alternative transfer approaches (taxonomic

models)• New models – benchmark against existing

approaches

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Topics covered - Effects

• Presentations by participants – setting the scene• Multispecies population modelling (J Vives).• DebTox modelling (F. Alonzo)• Radiobiology data archives (T. Sazykina)• Non-targeted and inheritable effects (C. Mothersill)• Transfer, exposure & effects – TREE (D. Copplestone)• Project REDFIRE (N. Beresford)

• Discussion “what questions does the IAEA expect the group to answer”

• Initial projects to start (what, link to regulation, who)• Discussion MODARIA I WG9 effects report

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Questions that IAEA would like addressed

• What is the dose rate at which we can start seeing effects at the population(s) / ecosystem level?• We are not planning to produce benchmarks but come with

sound advice and consider how/if population models can be used to support this advice.

• What percentage of the population needs to be affected in order for the effect to affect the whole population? • ‘Signalling’, spatial distribution – this is an integrating activity

between the two teams of WG5.

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Questions that IAEA would like addressed

• How robust are the existing benchmarks for exposure to biota populations?• Issues like past exposures, population migration, what data are

appropriate to use and how we interpret them (contribute to debate on field effects at ‘low’ dose rates).

• Provide evidence-based arguments to defend benchmarks when they are challenged by stakeholders.

• Important clarification• We are using population models as a tool to answer the

questions but we are not suggesting population models be used as part of regulatory assessments.

• We will consider new data becoming available.

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Start-up tasksItem Description Regulatory justification Who

Impact on modelling of inheritable effects

Look at data that already exists giving an indication of transfer across the generations

Based on data available, adapt population model formulism to account for inherited effects

Develop generic guidance on how to design a suitable experiment and attempt an in-house experiment to give us extra data to model.

Robustness of benchmarks Data –Mothersill, Copplestone, Real?

Modelling – Kryshev, Vives, Alonzo?, Copplestone

Experimental Copplestone, Wood, Beresford, IRSN, Mothersill et al.

Historical doses

Calculating historical doses for Fukushima & Chernobyl to evaluate the implications of historical exposure on currently observed effects.

Explore potential to factorise organism mobility and the spatial extent of contaminated sites.

Give regulators the ability to defend (or not) benchmark values.

Wood, Beaugelin, Copplestone, Beresford, Mothersill

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Start-up tasks (continuation)Item Description Regulatory justification WhoExploring species interaction in population models

Find a dataset for a closed ecosystem’ with several species e.g. a pond that could be used as a test dataset for modelling.

If this information exists we can use it to apply population model for interacting species.

Defensibility of benchmark values / ecosystem endpoints - Do interactions between species have implications for benchmark selection.

Vives, Alonzo?, Copplestone, Bradshaw, Real?

Review of population modelling approaches in chemicals regulation

How population modelling has influenced benchmarks with regards to chemicals (pesticides, metals, organics) – produce summary of what has been done for chemicals regarding population modelling.

Consistency of approach Biermans, Beresford, Bradshaw?, Hansen

Spatial aspects of population modelling

What size of a sub-population needs to be exposed to radiation in order to have an effect on the whole population? Literature review and population modelling task – do this through one or several case studies

Robustness of benchmarks

Wood, Beresford, Copplestone, Vives

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Plans for finishing MODARIA I report

WG9• Individual chapters already drafted in most cases• Create ‘core’ group to finish report (Alonzo,

Copplestone, Real, Vives, Wood)• Peer review phase by the wider group and delivery to

IAEAWG8• Some chapters drafted & some on-going

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Parting messages

• For MODARIA II we focus on the link between the science and the regulatory issues

• Produce output for our stakeholder - IAEA• Well motivated team (includes new people)• Keep the activity alive between meetings • An appeal to the audience – we need to gather

information to feed gaps in the effects for some doses within the benchmark bands

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Mid-term meeting

Aim to try to co-ordinate with WG1