Simulating dissolved 90Sr concentrations within a small catchment in the Chernobyl Exclusion Zone using a parametric hydrochemical model.
Simulating dissolved 90Sr concentrations within a small catchment in the Chernobyl Exclusion Zone using a parametric hydrochemical model.
复制标题
使用参数水化学模型模拟切尔诺贝利禁区小流域内溶解的 90Sr 浓度。
DOI：
10.1038/s41598-020-66623-4
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发表时间：
2020
影响因子：
4.6
通讯作者：
Igarashi Y
中科院分区：
文献类型：
--
作者：
Igarashi Y
锶-90(90Sr)是切尔诺贝利事故中主要的长寿命放射性核素，目前仍在切尔诺贝利隔离区严重污染的集水区中被检测到。这项研究考察了自事故发生以来，溪水中溶解相~(90)锶浓度的长期下降和浓度-排放关系(~(90)Sr-Q)。结果表明，~(90)锶的缓慢下降服从双指数函数，并且~(90)锶与Q之间存在明显的关系。这项研究首次揭示了事故以来对数(90锶)-对数(Q)斜率呈逐渐减小的趋势。在衰退修正后，这一趋势仍将持续。因此，这不是由~(90)Sr的物理衰变和环境扩散引起的，而是暗示了溪水中浓度的形成过程在很长一段时间内一直在变化。我们提出了一个水化学模型来解释~(90)Sr-Q关系的时间依赖性。本文提出了这一新概念的数学实现，并描述了模型假设。我们的模型既准确地反映了溪水中~(90)Sr的长期趋势，又准确地反映了~(90)Sr-Q关系的时间依赖性。尽管本文考虑了切尔诺贝利的一个小集水区，但概念模型也适用于其他放射性核素的意外泄漏。
Strontium-90 (90Sr) is the major long-lived radionuclide derived from the Chernobyl accident, and is still being detected in the heavily contaminated catchments of the Chernobyl Exclusion Zone. This study examines the long-term decrease in the dissolved-phase90Sr concentration and the concentration–discharge (90Sr-Q) relationship in stream water since the accident. We show that the slow decline in90Sr follows a double-exponential function, and that there is a clear relationship between90Sr andQ. This study is the first to reveal that the log(90Sr)-log(Q) slope has been gradually decreasing since the accident. This trend persists after decay correction. Thus, it is not caused by the physical decay of90Sr and environmental diffusion, but implies that the concentration formation processes in stream water have been changing over a long period. We propose a hydrochemical model to explain the time-dependency of the90Sr-Qrelationship. This paper presents a mathematical implementation of the new concept and describes the model assumptions. Our model accurately represents both the long-term90Sr trend in stream water and the time-dependency of the90Sr-Qrelationship. Although this paper considers a small catchment in Chernobyl, the conceptual model is shown to be applicable to other accidental releases of radionuclides.