Estimation of radioecological sensitivity

After the release of radionuclides into the environment it is important to be able to readily identify major routes of radiation exposure, the most highly exposed individuals or populations and the geographical areas of most concern. There have been significant recent improvements in our capability to estimate spatial variation in the environmental behaviour of radionuclides through better understanding of the underlying processes and an ability to spatially apply this knowledge by integrating relevant spatial information in the form of digital data sets using geographical information systems. Thus, it is now possible to refine the estimation of spatial variation in radiation exposure, both for routine releases and in accident situations. Within a recent EC-funded concerted action (the Radioecological Sensitivity Forum), there has been a renewed consideration of the concept of radioecological sensitivity with a particular focus on identifying sensitive areas as well as processes and communities. The concept should be relevant for both terrestrial and aquatic ecosystems, and might even be applied for consideration of doses to biota, although the current focus has been restricted to a consideration of human exposure. The conclusions of the action are outlined, considering the potential usefulness of the concept, and methods by which it can be applied. A framework for the estimation of radioecological sensitivity is proposed and the various measures by which it can be considered, including (i) aggregated transfer coefficients, (ii) action loads, (iii) fluxes and (iv) individual exposure of humans are discussed. The importance of spatial and temporal consideration of each of these outputs is emphasized.