Revision of deposition and weathering parameters for the ingestion dose module (ECOSYS) of the ARGOS and RODOS decision support systems Kasper G. Andersson a, * , Sven P. Nielsen a , Håvard Thørring b , Hanne S. Hansen b,1 , Hans Pauli Joensen c , Mats Isaksson d , Eila Kostiainen e , Vesa Suolanen f , Sigurdur Emil Pálsson g a Risø National Laboratory for Sustainable Energy, Technical University of Denmark, P.O. Box 49, DK-4000 Roskilde, Denmark b Norwegian Radiation Protection Authority, P.O. Box 55, 1332 Østerås, Norway c Faculty of Science and Technology, University of Faroe Islands, Nóatún 3, FO-100 Tórshavn, Faroe Islands d Department of Radiation Physics, Institute of Clinical sciences, the Sahlgren Academy, University of Gothenburg, SE 413 45 Gothenburg, Sweden e Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland f VTT Technical Research Centre, P.O. Box 1000, FI-02044 VTT, Espoo, Finland g Icelandic Radiation Safety Authority, Raudararstig 10, IS-150 Reykjavik, Iceland article info Article history: Received 9 March 2011 Received in revised form 6 June 2011 Accepted 16 June 2011 Available online 23 July 2011 Keywords: ECOSYS model Decision support Nuclear emergencies Ingestion dose Weathering Deposition abstract The ECOSYS model is the ingestion dose model integrated in the ARGOS and RODOS decision support systems for nuclear emergency management. The parameters used in this model have however not been updated in recent years, where the level of knowledge on various environmental processes has increased considerably. A Nordic work group has carried out a series of evaluations of the general validity of current ECOSYS default parameters. This paper specifically discusses the parameter revisions required with respect to the modelling of deposition and natural weathering of contaminants on agricultural crops, to enable the trustworthy prognostic modelling that is essential to ensure justification and optimisation of countermeasure strategies. New modelling approaches are outlined, since it was found that current ECOSYS approaches for deposition and natural weathering could lead to large prognostic errors. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction More than any other tools, the ARGOS and RODOS decision support systems constitute the prognostic ‘spine’ in European preparedness against accidents at nuclear installations. The systems deliver crucial information that can be used for justifica- tion and optimisation of countermeasure strategies during different time phases, thus assisting in effectively reducing the adverse health impacts through different pathways. The module for estimating ingestion dose is in both systems the ECOSYS model, which was developed in the 1980’s. The integration of this origi- nally general prognostic model in complex decision support systems making use of, e.g., site specific measurement data and prognostic weather data, has called for incorporation also in ECO- SYS of more case specific parameter data. However, contrary to recommendations from its originators, this model has undergone very few parametric changes by its many users since it was created, and default parameter values, which are generally applied uncrit- ically, do not reflect the best knowledge of today, specifically considering the requirements of modern decision support systems. The problem is twofold: (i) scientific investigations made over the several decades since ECOSYS was created (including those relating to the Chernobyl accident) have considerably advanced the state of knowledge on generic processes and parameters governing the contaminant deposition and migration in the agricultural envi- ronment as well as the transfer through associated food chains, while at the same time enabling the use in decision support systems of more case specific data, and (ii) a number of the input parameters in ECOSYS depend on country or region specific conditions, but the model is generally used with the default dataset that was derived for South German conditions. A Nordic work group aims to address the generic parameterisation problem in ECOSYS, while also deriving values that represent the local condi- tions in each of the Nordic countries (Denmark, Norway, Sweden, Finland, Iceland, and the Faroe Islands). More specifically, the work * Corresponding author. Tel.: þ45 4677 4173; fax: þ45 4677 5330. E-mail address: kasper.andersson@risoe.dk (K.G. Andersson). 1 Present address: Nord-Trøndelag University College, Service Box 2501, N-7729 Steinkjer, Norway. Contents lists available at ScienceDirect Journal of Environmental Radioactivity journal homepage: www.elsevier.com/locate/jenvrad 0265-931X/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvrad.2011.06.006 Journal of Environmental Radioactivity 102 (2011) 1024e1031