Overview of the MODARIA programme (and comments on implications for future programmes of work) ^*

Abstract

The International Atomic Energy Agency (IAEA) has organised programmes on the development, comparison and testing of environmental assessment models and approaches for estimating the radiation exposure of humans and wildlife since the 1980s. The latest of these programmes was called MODARIA (Modelling and Data for Radiological Impact Assessment) and was run in two phases from 2012 to 2015 (MODARIA I) and 2016 to 2019 (MODARIA II). Both phases of the MODARIA programme had the overall objective to improve capabilities in the field of environmental transfer of radionuclides and public and non-human biota exposures assessment, by means of acquisition of improved data for model testing and comparison, reaching consensus on modelling philosophies, approaches and parameter values and building an international forum for the exchange of information. This paper provides an overview of the work undertaken during both phases of the MODARIA programme and its outputs. The overall aims and objectives of a new programme to follow on from MODARIA are described.

Improving models and data for radiological impact assessment: work carried out under the IAEA MODARIA programme

“…This was followed up by MODARIA II, concluding in 2019.The thematic coverage of these programmes has been broad, with MODARIA II covering subjects as diverse as: naturally-occurring radioactive materials (NORM) and nuclear legacies; contamination in urban environments; integrated assessment for people and other biota; radioecological data; exposure and effects on biota; biosphere modelling for waste disposal facilities; and radionuclides in the marine environment. Comprehensive information summarising the background, context, content and overall outcomes is provided in this issue by Brown et al (2022).The set of papers presented here, in combination, demonstrate the connectedness of site and radiological source term characterisation; methods for analysis of the current disposition and future migration or dispersion of radionuclides; behaviour of human and other biota groups relevant to the assessment of exposure; and how all of that supports the practical application of international standards and risk-informed decision making. Consider, for example, three papers linked to existing exposure situations:…”

“…The thematic coverage of these programmes has been broad, with MODARIA II covering subjects as diverse as: naturally-occurring radioactive materials (NORM) and nuclear legacies; contamination in urban environments; integrated assessment for people and other biota; radioecological data; exposure and effects on biota; biosphere modelling for waste disposal facilities; and radionuclides in the marine environment. Comprehensive information summarising the background, context, content and overall outcomes is provided in this issue by Brown et al (2022).…”

Pre- and post-accident environmental transfer of radionuclides in Japan: lessons learned in the IAEA MODARIA II programme

“…Application of this techniques allowed the estimation of biological half-lives T b of Cs-137 in cattle. A recent review of T b data suggested that there are two components of loss for Cs with half-lives of 1.4 d (80% of total activity) and 15 d (20% of total activity) for milk and 9 d (56% of total activity) and 53 d (44% of total activity) for beef (Brown et al 2022).…”

Updated soil to fruit concentration ratios for radiocaesium compiled under the IAEA MODARIA II Programme

“…TECDOC 1927 includes data for radiocaesium transfer to fruit, particularly for fruit from woody trees. The TECDOC is an output of Working Group 4 (WG4) 'Transfer Processes and Data for Radiological Impact Assessment' of the IAEA MODARIA II (Modelling and Data for Radiological Impact Assessments) Programme [21]. Also, within the MODARIA II WG4, the CR data from TRS 472 for root uptake by crops growing in tropical climates were updated [22] and the first international dataset of CR values for crops growing in arid climates was compiled [23].…”