Further development of transfer and exposure models and application - - PowerPoint PPT Presentation

WG-8 Biota modelling: Further development of transfer and exposure models and application to scenarios

Activities agreed Nov. 2012

• Modelling exposure in spatially heterogeneous

environments

• Simple whole-organism ellipsoid geometries v’s

Voxel phantoms

• Develop scenario for Fukushima marine

environment

• Collate biological half-life data for wildlife
• Guidance documentations .... Lessons learnt

EMRAS I & II

Estimating soil contamination in home ranges of different species

Modelling spatially heterogeneous environments

• WHY: Typically simplistic

– Point of capture media concentrations – Average over likely home- range

• Is that good enough?

Modelling spatially heterogeneous environments

• Review of approaches used in other fields
• Presentation of potential datasets for

modelling

• Aim: Select scenario(s) to be modelled
• ver the next year(s)

Photos: Sergey Gashchack (Chornobyl Center)

Dosimetry

• WHY: Whole-organism dose rates

estimated assuming homogenous (ellipsoid) geometry

Dosimetry

Dosimetry

• Are simple models

sufficient?

Liz Ruedig Colorado State

Dosimetry

Why: Activity concentrations measured/predicted without GIT - Should we ignore dose (& foodchain transfer) from GIT contents?

Mat Johansen (ANSTO)

Dynamic models

• WHY: Assume equilibrium

– Some criticism – Is it conservative? – Not suitable for modelling accidental releases

Fukushima scenario

• Water & sediment inputs supplied by

WG10 (predictions to end July 2011)

– Cs-137, Sr-90, I-131

• Results submitted by 7 modellers

– Including one set from ERICA (equilibrium) for comparison

• Methods to be presented & discussed

– Provisional comparison

Biological half-lives for wildlife

• Species/ecosystems divided amongst

participants (Nov 2012)

• Spreadsheet to record data supplied
• Preliminary reports in May 2013 – update this

meeting

Guidance documentation

• Suggested by a number of participants:

– On basis of what learnt from EMRAS etc. provide guidance on wildlife assessments (e.g. coping with missing data, considering decay series, are some models better for certain elements of assessment than others, are dose rate benchmarks fit for purpose)

Sub-group to meet before the main group to focus this activity

Publications

MP Johansen, E Ruedig, NA Beresford, K Tagami, S Uchida. Sequestration of 137Cs in marine fish tissues and organ-specific dose modelling: data review and recommendation for future sampling (Sub: IAEA ‘Fukushima’ meeting 2014)

Submitted to Barcelona conference:

MD Wood, NA Beresford, C Bradshaw, S Gaschak. Advances in environmental radiation protection: re-thinking animal- environment interaction modelling for wildlife dose assessment NA Beresford, J Vives i Batlle, M Johansen, R Goulet, K Beaugelin-Seiller, P Andersson , K Stark, E. Ruedig, MD Wood, S Fesenko. Modelling the exposure of wildlife to radiation: key findings and activities of IAEA working groups

Outline agenda

• Wednesday morning after plenary: sub-

group only to meet to discuss ‘guidance documentation’

– P. Andersson, K. Beaugelin-Seiller, N.A. Beresford, D. Copplestone, M. Johansen, K. Stark, H. Vandenhove, M. Wood, T. Yankovich

• Wednesday 13:30 onwards

– Fukushima scenario (with WG10) – Biological T1/2 review (inc. C & OBT modelling)

Outline agenda -Thursday

– Comparing Voxel phantoms with homogenous assumptions – Dose from GIT (marine fish) – Effect of soil moisture on DCCs – Overview of methods used for ‘spatial exposure’ – Presentation & selection of potential spatial datasets (inc some planned studies) – Biological T1/2 review - complete if not finished Wednesday (will be afternoon) – Updates