As an essential form of material migration on the surface of the earth, soil erosion is one of the primary causes of soil fertility reduction and environmental degradation. Quantifying soil erosion rate is the precondition and foundation for regional soil erosion control. The Pu isotopes produced by atmospheric nuclear tests have a long half-life after settling into the soil and could be easily adsorbed by clay minerals and organic matter. In recent years, Pu isotopes have become principal trace elements in the quantitative studies of soil erosion rate, especially with the development of mass spectrometry technique. The measurement time of Pu isotopes has been shortened, and the sensitivity of Pu isotopes has been improved, both of which help improve the radionuclide tracing technology for soil erosion. Here, we summarized the distribution characteristics as well as the adsorption and migration behavior of Pu isotopes in soil. We described the basic principles for the application of Pu isotopes in tracing soil erosion, and elaborated the research progress concerning relevant applications. Moreover, we compared the applicability of Pu isotope and 137Cs tracing techniques in soil erosion research and proposed research directions in the future. This review would provide a reference for the scientific applications of Pu isotope tracing technique in soil erosion research.
土壤侵蚀是地球表面物质迁移的重要形式,也是造成土壤肥力下降和生态环境退化的重要诱因之一,对土壤侵蚀速率的定量研究是进行区域土壤侵蚀治理的前提和基础。大气核试验产生的Pu同位素具有较长的半衰期,其沉降到土壤中易被土壤中的黏土矿物和有机质吸附,近年来被认为是定量研究土壤侵蚀速率的重要示踪元素,尤其是质谱技术的发展,缩短了Pu同位素的测量时间并提高了其测量灵敏度,大力推动了土壤侵蚀核素示踪技术的发展。本文在梳理已有相关研究的基础上,总结土壤中Pu同位素的分布特征及吸附与迁移行为,阐述了应用Pu同位素示踪土壤侵蚀的基本原理和应用研究进展,并对Pu同位素和137Cs示踪技术在土壤侵蚀研究中的适用性进行比较分析,对未来研究方向提出展望,以期为科学应用Pu同位素示踪技术研究土壤侵蚀提供参考。.
Keywords: Pu isotope; distribution characteristic; soil erosion; tracing application.