MODARIA MODARIA WG4 Analysis of radioecological data in IAEA TRS to identify key radionuclides and associated parameter values for human and wildlife assessment
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 Pine Wild Earth- Deer Rat Duck Tree Frog Grass Bee 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
Pine Wild Earth- Deer Rat Duck Tree Frog Grass Bee 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 Terrestrial Cs Cs Cs Cs Cs RAPs High *La priority 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 • K d 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 K d values for freshwater, soils, and marine environments • the derivation of published values which are suitable for the needs for modelers • the provision of K d values which take account of known factors which lead to variation in K d 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 K d
Outcome The targets for the databases should initially be to compile sufficient data to construct PDFs for K d of key dose-forming RN relevant for human / other organisms.
Approach Transform the existing freshwater and soils compilations into independent databases sharing the same software and a common structure. • determine data acceptance criteria • discuss and decide a common database structure • transfer existing compilations to databases • decide common approaches for statistical treatments.
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 C s vs. C eq range could be entered. � Data not representative of environmental conditions to better evaluate the role of cofactors ( e.g ., K d obtained at extreme values of pH, E h , ionic strength…). � For replicates values for a same location, conditions and reference - only average values used and not the results of each individual analytical replicate.
Outstanding issues • construction of an “intelligent” database • production of a guidance/help document. • feasibility of constructing a database for K d 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 of environmental or other factors to explain observed variability
And • Where it is not needed! • So order of magnitude estimates may suffice
Recommend
More recommend
