由于高浓度下的高放射性毒性,以及量化土壤侵蚀率的不可替代性,划分人类世,和沉积物的年代测定,人为239,240Pu引起了高度重视。然而,特定领域的来源,在不同环境介质中的保存特性,以及停止大气核武器试验后的重新分配过程,还没有被完全理解,这掩盖了确切的开始年,时间变化,沉积记录中的沉积通量为239,240Pu,阻碍了239,240Pu在环境研究中的广泛应用。来自义乌泥炭沼泽的沉积物核心,在源物质中占大气沉积的主导地位,简单的沉积环境,和高粉尘沉积通量,被收集来检查239,240Pu,探索源头,保存,和重新分配过程。1952年和1963年的239240Pu双峰,以及240Pu/239Pu比率为0.163-0.190,平均为0.177±0.010,证实了239,240Pu源主要来自全球尘埃。义乌泥炭岩心中钚的最小垂直迁移归因于接近中性的pH条件。高库存为128±7Bqm-2,239,240Pu浓度与有机质含量呈非典型负相关(r=-0.79,P<0.01),归因于239,240Pu被邻近戈壁沙漠的灰尘重新悬浮,特别是在寒冷和干燥的年代。重新暂停的239,240Pu总数估计为77Bqm-2,超过了1945-2016年CE期间的直接沉降水平51Bq/m2。在这项研究中,确定停止大气层核武器后的239240Pu的特定沉积模式,为多种环境研究提供重要标准,首次量化了典型干旱区的重悬浮量239,240Pu。
Owning to the high radiotoxicity in high concentrations, as well as the irreplaceability in quantifying soil erosion rates, demarcating the Anthropocene, and dating of sediment, anthropogenic 239,240Pu have drawn high attention. However, the source in specific areas, preservation characteristics in different environment media, and re-distribution process after the cessation of atmospheric nuclear weapons tests, have not been fully understood, which obscures the exact start year, temporal variation, and deposition flux of 239,240Pu in sedimentary records, and hinders the wide application of 239,240Pu in environment study. A sediment core from the Yiwu peat bog with dominance of atmospheric deposition in the source material, simple sedimentary environment, and high dust deposition flux, was collected to examine the 239,240Pu, and explore the source, preservation, and re-distribution process. The double peaks of 239,240Pu in 1952 CE and 1963 CE, as well as 240Pu/239Pu ratios of 0.163-0.190 with an average of 0.177 ± 0.010 confirmed that the 239,240Pu source originated predominantly from global fallout. The minimal vertical migration of plutonium in the Yiwu peat core was attributed to the near-neutral pH condition. The high inventory of 128 ± 7 Bq m-2, as well as the atypical negative correlation between 239,240Pu concentrations and organic matter content (r = - 0.79, P < 0.01), was attributed to the contribution of 239,240Pu re-suspended with dust from the neighboring Gobi Desert, particularly in the cold and dry years. The total re-suspended 239,240Pu was estimated to be 77 Bq m-2, exceeding the direct fallout level of 51 Bq m-2 during 1945-2016 CE. In this study, the specified deposition pattern of 239,240Pu after the cessation of atmospheric nuclear weapons was established, providing an important standard for multiple environmental studies, and the re-suspended amount of 239,240Pu in a typical arid area was quantified for the first time.