Radionuclide Transport and Uptake in Coastal Aquatic Ecosystems: A Comparison of a 3D Dynamic Model and a Compartment Model

Anders Christian Erichsen,Flemming Møhlenberg,Lena Konovalenko,Ulrik Kautsky,Clare Bradshaw,Karin Aquilonius,Rikke Margrethe Closter

doi:10.1007/s13280-013-0398-2

Abstract

In safety assessments of underground radioactive waste repositories, understanding radionuclide fate in ecosystems is necessary to determine the impacts of potential releases. Here, the reliability of two mechanistic models (the compartmental K-model and the 3D dynamic D-model) in describing the fate of radionuclides released into a Baltic Sea bay is tested. Both are based on ecosystem models that simulate the cycling of organic matter (carbon). Radionuclide transfer is linked to adsorption and flows of carbon in food chains. Accumulation of Th-230, Cs-135, and Ni-59 in biological compartments was comparable between the models and site measurements despite differences in temporal resolution, biological state variables, and partition coefficients. Both models provided confidence limits for their modeled concentration ratios, an improvement over models that only estimate means. The D-model enables estimates at high spatio-temporal resolution. The K-model, being coarser but faster, allows estimates centuries ahead. Future developments could integrate the two models to take advantage of their respective strengths.Electronic supplementary materialThe online version of this article (doi:10.1007/s13280-013-0398-2) contains supplementary material, which is available to authorized users.

Highlights

Nuclear power plants and nuclear waste storages facilities undergo frequent safety assessments to explore the fate of actual or hypothetical releases of radionuclides from the Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users
The fate of release of radionuclides to the biosphere and the coastal marine ecosystem is of interest
The marine ecosystems at the site and other important site data are described in Aquilonius (2010), who summarizes site data such as hydrodynamics, chemical and physical characteristics, biota types and biomass, as well as quantification of ecosystem processes

Summary

Introduction

Nuclear power plants and nuclear waste storages facilities undergo frequent safety assessments to explore the fate of actual or hypothetical releases of radionuclides from the Electronic supplementary material The online version of this article (doi:10.1007/s13280-013-0398-2) contains supplementary material, which is available to authorized users.facilities. A final repository for spent nuclear fuel is currently being planned at Forsmark, Sweden For such a facility, this means that the time frame is up to a million years (Kautsky et al 2013) and may include several periods of glaciation (Naslund et al 2013) and long-term changes such as shore-line displacement and succession of the landscape from marine ecosystems, through lakes and mires, to terrestrial ecosystems (Lindborg et al 2013), as well as changes in expected human behavior (Saetre et al 2013). The fate of release of radionuclides to the biosphere and the coastal marine ecosystem is of interest

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