[Application of Pu isotope tracing technique in soil erosion research]

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.