EJP-CONCERT. D9.17 – CONFIDENCE: overview of model improvements and future needs

Beresford, N.A.; Barnett, C.L. ORCID: https://orcid.org/0000-0001-9723-7247; Brown, J.E.; Hosseini, A., eds. 2019 EJP-CONCERT. D9.17 – CONFIDENCE: overview of model improvements and future needs. European Joint Programme for the Integration of Radiation Protection Research, 42pp.

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Abstract/Summary

EJP-CONCERT Work Package 9, Deliverable 9.17. There are considerable uncertainties associated with the radioecological simulation models used to predict the transfer of radionuclides in human foodstuffs. Initially after an accidental release of radioactivity, the factors determining the contamination of foodstuffs will largely be defined by vegetation interception and the time of year. During the transition phase, factors controlling the uptake of radionuclides to vegetation from soil will become more important and these will dominate during the long-term rehabilitation phase. However, predictions made using radioecological models will be used in the early part of the transition phase to make longer-term decisions, such as those associated with remediation strategies. Therefore, models must be sufficiently robust and fit for purpose with uncertainties reduced where practicable. This deliverable presents an overview of activities within the CONFIDENCE project to improve the capabilities of radioecological models used to make predictions of radionuclide contamination in human foodstuffs. The work programme addressed three over-arching and interlinked tasks: (i) ‘Improving models’ (uncertainty/sensitivity analyses, 131I tracer studies, evaluation of extrapolation approaches, parameter dataset compilation); (ii) an evaluation of process-based soil-plant models; (iii) consideration of the inclusion of fuel particles in radioecological models. The key outputs and findings of these activities were: • The incorporation of the food chain transfer module (FDMT) from the JRodos Decision Support System into a flexible modelling platform (ECOLEGO) allowing, for instance, sensitivity analyses, investigation of regionalisation and the replacement of default empirical model components with process-based models. • Development of process-based soil-plant models for Sr. • Identification of the strengths and weaknesses of the Absalom process-based soil-plant model for Cs. • Development of a model of the behaviour of particle associated radionuclides in soil-plant systems. • Recommendation that in the short-term, process-based soil-plant models (for Cs, Sr and fuel particles) will generally give no added benefit, i.e. models such as FDMT are sufficient for predictions during this phase (because soil-plant transfer contributes little to radionuclide activity concentrations of crops in the short-term). However, longer-term predictions made using FDMT, or similar models, during the early phase after a deposition event should be communicated with care. • Recommendation that for remediation planning, process-based models are applied once reliable deposition maps are available to enable the identification of areas where food products are likely to remain contaminated in the longer-term. • Demonstration of the predictive power (and problems) of proposed phylogenetic models for predicting Cs and Sr activity concentrations in crops. • Publication of a dataset of radionuclide biological half-lives for farm animal products. • Derivation and publication of a dataset of transfer parameters for Mediterranean systems including regionally important foodstuffs. • Experimental studies showing that: (i) there is negligible root uptake of 131I by crops; (ii) there is transfer of 131I deposited onto foliage to fruits and tubers; (iii) the presence of (goitrogenic) rapeseed in the diet of cows reduced the transfer of 131I from blood to milk. • The parameters in the FDMT model, as used in JRodos, should be reviewed and updated. Recommendations for future model improvements (including experimental and communication requirements) based upon the findings of the studies conducted and consultations with end-users are presented.

Item Type:	Publication - Report
UKCEH and CEH Sections/Science Areas:	Pollution (Science Area 2017-)
Funders/Sponsors:	European Union Horizon 2020
Additional Keywords:	radioecology, food chain, transfer factors, probabilistic modelling, process-based models, fuel particles, Mediterranean, caesium, strontium, iodine
NORA Subject Terms:	Ecology and Environment
Related URLs:	Project Website
Date made live:	06 Feb 2020 15:33 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/526406

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