Department of Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom.
Department of Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom.
Environ Pollut. 2018 Sep;240:191-199. doi: 10.1016/j.envpol.2018.04.112. Epub 2018 May 5.
Cs-137 is considered to be the most significant anthropogenic contributor to human dose and presents a particularly difficult remediation challenge after a dispersal following nuclear incident. The Chernobyl Nuclear Power Plant meltdown in April 1986 represents the largest nuclear accident in history and released over 80 PBq of Cs into the environment. As a result, much of the land in close proximity to Chernobyl, which includes the Polessie State Radioecology Reserve in Belarus, remains highly contaminated with Cs to such an extent they remain uninhabitable. Whilst there is a broad scale understanding of the depositional patterns within and beyond the exclusion zone, detailed mapping of the distribution is often limited. New developments in mobile gamma spectrometry provide the opportunity to map the fallout of Cs and begin to reconstruct the depositional environment and the long-term behaviour of Cs in the environment. Here, full gamma spectrum analysis using algorithms based on the peak-valley ratio derived from Monte Carlo simulations are used to estimate the total Cs deposition and its depth distribution in the soil. The results revealed a pattern of Cs distribution consistent with the deposition occurring at a time of flooding, which is validated by review of satellite imagery acquired at similar times of the year. The results were also consistent with systematic burial of the fallout Cs by annual flooding events. These results were validated by sediment cores collected along a transect across the flood plain. The true merit of the approach was confirmed by exposing new insights into the spatial distribution and long term fate of Cs across the floodplain. Such systematic patterns of behaviour are likely to be fundamental to the understanding of the radioecological behaviour of Cs whilst also providing a tracer for quantifying the ecological controls on sediment movement and deposition at a landscape scale.
铯-137 被认为是人类剂量的最重要的人为贡献者，并且在核事故后分散后，呈现出特别困难的修复挑战。1986 年 4 月切尔诺贝利核电站熔毁是历史上最大的核事故，向环境中释放了超过 800 PBq 的铯。结果，切尔诺贝利附近的大部分土地，包括白俄罗斯的波列西耶州放射生态学保护区，仍然受到高度铯污染，以至于仍然无法居住。虽然对禁区内外的沉积模式有广泛的了解，但详细的分布测绘通常受到限制。移动伽马光谱学的新发展提供了绘制铯沉降物的机会，并开始重建沉积环境和环境中铯的长期行为。在这里，使用基于蒙特卡罗模拟得出的峰谷比衍生算法进行全伽马光谱分析，以估计土壤中的总 Cs 沉积量及其深度分布。结果显示 Cs 分布模式与洪水时期的沉积一致，这通过对同年类似时间获取的卫星图像进行审查得到了验证。结果也与每年洪水事件对沉降 Cs 的系统掩埋一致。这些结果通过在洪水泛滥平原上沿横断面采集的沉积物芯得到了验证。通过揭示洪水泛滥平原上 Cs 的空间分布和长期命运的新见解，证实了该方法的真正价值。这种系统的行为模式可能是理解 Cs 的放射生态学行为的基础，同时也为量化景观尺度上沉积物运动和沉积的生态控制提供示踪剂。
