Biosphere Impact Studies Unit, Belgian Nuclear Research Centre, Boeretang 200, 2400, Mol, Belgium.
Institute for Landscape Ecology and Resources Management (ILR), Research Centre for BioSystems, Land Use and Nutrition (IFZ), Justus Liebig University Giessen, Giessen, 35392, Germany.
J Environ Radioact. 2020 Dec;225:106380. doi: 10.1016/j.jenvrad.2020.106380. Epub 2020 Oct 1.
Mathematical models are frequently used in terrestrial radioecology to interpret observations and to assess the detrimental impacts of radioactive releases to the environment. Conventional radioecological models are largely based on equilibrium and empirical relationships with reasonable data requirements, making them practical tools for long-term assessments. But conventional models may be inadequate to simulate radionuclide dynamics in terrestrial environments realistically. Specifically, the structure of such models seldom conforms to the physics of water flow and solute transport in soils. The equilibrium relationships may fail to predict seasonality in radionuclide transfer between environmental compartments; model transferability between sites is often hampered by its empirical nature. Numerous studies have highlighted the need to circumvent these limitations. In this paper, we introduce dynamic and process-based modelling to a conventional radioecological model by coupling an empirical plant module to a process-based soil module that simulates water flow, solute transport and root uptake in the soil column. Illustrative simulations are presented using the coupled model and stable chlorine cycling in a temperate Scots pine (Pinus sylvestris L.) stand as an example. The model satisfactorily reproduced soil moisture dynamics and the inventory of inorganic chlorine in the tree and forest floor compartments. The inventory of organic chlorine in the stand, however, was overestimated, indicating that processes pertinent to organochlorine cycling at the stand were missing from the model. The approach proposed in this paper is a step towards dynamic and process-based modelling in terrestrial radioecology and impact assessment. It can be particularly useful for modelling transfer of elements, such as redox-sensitive radionuclides, whose behaviour in soil-plant systems is moisture-dependent.
数学模型常用于陆地辐射生态学，用于解释观测结果并评估放射性物质释放对环境的有害影响。传统的辐射生态学模型主要基于平衡和经验关系，具有合理的数据要求，因此是长期评估的实用工具。但是，传统模型可能无法真实地模拟陆地环境中的放射性核素动态。具体而言，此类模型的结构很少符合土壤中水流和溶质运移的物理规律。平衡关系可能无法预测环境组分之间放射性核素转移的季节性；由于其经验性质，模型在站点之间的可转移性常常受到阻碍。许多研究强调需要规避这些限制。在本文中，我们通过将经验性植物模块耦合到模拟土壤柱中水流、溶质运移和根系吸收的基于过程的土壤模块，将动态和基于过程的建模引入传统的辐射生态学模型中。使用耦合模型和温带苏格兰松（Pinus sylvestris L.）林的稳定氯循环为例，展示了说明性模拟。该模型令人满意地再现了土壤水分动态以及树木和林地表层中无机氯的库存。然而，林分中有机氯的库存被高估，这表明与林分中有机氯循环有关的过程缺失了模型。本文提出的方法是陆地辐射生态学和影响评估中动态和基于过程的建模的一个步骤。对于模拟土壤-植物系统中行为取决于水分的元素（如氧化还原敏感的放射性核素）的转移，该方法特别有用。
