MODARIA MODARIA WG4 Analysis of radioecological data in IAEA TRS - - PowerPoint PPT Presentation

Analysis of radioecological data in IAEA TRS to identify key radionuclides and associated parameter values for human and wildlife assessment

MODARIA

MODARIA WG4

IAEA Parameter value compilations

Objectives

Using the recent data compilations:

• Identify data gaps which matter
• Provide guidance on need for further data for

different source terms

• Explore ways to make TRS data more usable

by modelling community

• Consider both human and wildlife

Using TRS publications – identify which parameter values'

• Are potentially important contributors to dose
• Are likely to vary considerably due to:
• soil characteristics, climate, physico – chemical form, life

cycle stages, agricultural practices,

• Are based on adequate data
• Can be adequately derived using

appropriate extrapolation methods

• Need further data/consideration

Terrestrial RAPs ---- LOW Priority

RAPs

Deer Rat Duck Pine Tree Frog Wild Grass Bee Earth- worm Ag Ag Ca Ca Ca Ca Ca Ca Ca Ca Cd Cd Co Co Co Cr Cr Cr Cr Cr Cr Cr Cr Mn Mn Mn Mn Mn Mn Ni Ni Ni Ni Ni Ni Ni Ni Se Se Se Se Se Tc Tc Tc Tc Tc Tc Tc Zn Zn Zn Zr Zr Zr Zr

Terrestrial RAPs High priority

Deer Rat Duck Pine Tree Frog Wild Grass Bee Earth- worm Ag Am Am Am Am Am Am Am Am *Ba *Ba Cd Cd Cd Cf Cf Cf Cf Cf Cf Cf Cf Cl Cm Cm Cm Cm Cm Cm Cm Cm Cs Cs Cs Cs Cs *La Np Np Np Np Np Np Np Np Pa Pa Pa Pa Pa Pa Pa Pa Po Po Po Po Po Po Po Po Pu Pu Pu Pu Pu Pu Pu Pu Ra Ra Ra Ra Ra Ra Ra Ra Sr Sr Sr Sr Sr Sr Tc Te Te Th Th Th Th Th Th Th Th U U U U U U U U

Current Focus of WG4

• Data analysis / database updates
• Derivation of suitable values for

screening assessments

• Kd database – consistent

approach

• Soil
• Sediment – freshwater √

marine ?

SRS 19 update – human foodchain

Deriving conservative parameter values for screening assessments –What degree of conservatism is appropriate? –Which values are based on data - quality and quantity –Methods used when there are no data –How precise do we need to be? –How important is the parameter value to the dose –Are there relevant source terms? –Which element/parameter combinations deserve more attention

Revision and application of Kd values

Aim To harmonise the approach used to develop and extend the range of PDFs available To provide PDFs in a format applicable for modelling for soils and freshwater Collate new data and integrate into current databases Select appropriate statistics to analyse data to develop the PDFs

Interim meeting Oslo May 2014

Joint activity between the WG4 and the EC STAR project WP3 and 7. The aim was to provide a forum for discussion of:

• the development of a common database (DB) and the

selection criteria for Kd values for freshwater, soils, and marine environments

• the derivation of published values which are suitable for

the needs for modelers

• the provision of Kd values which take account of known

factors which lead to variation in Kd values

• methods and criteria to extrapolate data to fill data gaps

including analogue approaches

• the provision of summarized data to the international

community

• alternative approaches to modeling Kd

Outcome

The targets for the databases should initially be to compile sufficient data to construct PDFs for Kd of key dose-forming RN relevant for human /

• ther organisms.

Approach

• determine data acceptance criteria
• discuss and decide a common database structure
• transfer existing compilations to databases
• decide common approaches for statistical

treatments. Transform the existing freshwater and soils compilations into independent databases sharing the same software and a common structure.

Identified acceptance criteria

batch sorption, in situ desorption, batch desorption and in situ desorption with natural/stable isotopes (stable isotope data). x data from either diffusion experiments, parametric equations/models, no data from pure mineral phases (Initially) For sorption isotherms, a single value representative for the linear Cs vs. Ceq range could be entered. Data not representative of environmental conditions to better evaluate the role of cofactors (e.g., Kd obtained at extreme values of pH, Eh, ionic strength…). For replicates values for a same location, conditions and reference - only average values used and not the results

• f each individual analytical replicate.

Outstanding issues

• construction of an “intelligent” database
• production of a guidance/help document.
• feasibility of constructing a database for Kd

values in marine environments

WG4 activities in TM3

Monday

– Transfer parameters data collation and analysis – Identifying contributors to dose – Extrapolation approaches to derive values

Tuesday / Wednesday - Kd

• reporting from interim meeting, Kd info,

current status of data collations

• Detailed discussion to finalise database

structure and content

Key outcomes

Provide enhanced capability, using current or selected improved databases, to confidently identifying those element/transfer values which:

• Quantify high environmental mobility, and
• Lead to “relatively” high doses

Identify where there is a need to quantify influence

• f environmental or other factors to explain
• bserved variability

And

• Where it is not needed!
• So order of magnitude estimates may suffice