An analysis of the sensitivity of non-urban environments to radioactive contamination under the IAEA EMRAS-II program

Since the early 1980s the International Atomic Energy Agency (IAEA) had a succession of international programs to improve environmental transfer models for the assessment of radiological impacts on humans and non-human biota arising from radionuclides in the environment. The current EMRAS-II program (2009-2011) includes both routine and accidental emissions of artificial and natural radionuclides. This paper reports on the activities of Working Group 8 dealing with sensitive non-urban environments. First of all, the group has formulated a practical definition of environmental sensitivity. Then, in addition to conventional agricultural settings in the temperate zones, the group is studying special environments such as alpine, arctic, temperate forests, freshwater aquatic, and coastal marine environments. Initial modelling exercises are being carried out for depositions of the long-lived radionuclides 137Cs and 90Sr and the short-lived radionuclide 131I. Radionuclides concentrations are calculated in several environmental compartments, especially those leading to human exposures. Short term and long term radiation doses are calculated to the most exposed human populations. The results will aid in the planning and implementation of emergency as well as long-term countermeasures (e.g., sheltering, food-bans, decontamination) following a nuclear accident.