Department of Environmental Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark.
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.
Sci Total Environ. 2022 Feb 1;806(Pt 1):150482. doi: 10.1016/j.scitotenv.2021.150482. Epub 2021 Sep 23.
This work reports the first high-resolution deposition records of anthropogenic uranium (U and U) in a sediment core taken at the continental slope of the Philippine Sea off Mindanao Island in the equatorial northwest Pacific Ocean. Two notable peaks were observed in both profiles of U and U concentrations, with a narrower peak in 1951-1957 corresponding to close-in Pacific Proving Grounds (PPG) signal, and a broader peak in 1960s-1980s corresponding to the global fallout from nuclear weapons testing. U and U areal cumulative inventories in the studied sediment core are (2.79 ± 0.20) ∙ 10 atom ∙ m and (3.12 ± 0.41) ∙ 10 atom ∙ m, respectively, about 20-30% of reported U and U inventories from the direct global fallout deposition. The overall U/U atomic ratios obtained in this work vary within (0.3-3.5) ∙ 10, with an integrated U/U atomic ratio of (1.12 ± 0.17) ∙ 10. The contribution from global fallout and close-in PPG fallout to U in the sediment core is estimated to be about 69% and 31%, respectively. We believe the main driving process for anthropogenic uranium deposition in the Philippine sediment is continuous scavenging of dissolved U from the surface seawater by sinking particles.
本研究报告了在西北太平洋赤道海域棉兰老岛外菲律宾海大陆坡采集的沉积岩芯中首次高分辨率的人为铀（U 和 U）沉积记录。在 U 和 U 浓度的两个剖面中都观察到两个明显的峰值，其中 1951-1957 年对应于近域太平洋试验场（PPG）信号的峰较窄，而 20 世纪 60 年代至 80 年代对应于核武器试验的全球沉降物的峰较宽。在研究的沉积岩芯中，U 和 U 的面积累积库存分别为（2.79±0.20）∙10 原子∙m 和（3.12±0.41）∙10 原子∙m，分别约为直接全球沉降物中 U 和 U 库存的 20-30%。本工作获得的 U/U 原子比变化范围在（0.3-3.5）∙10 之间，综合 U/U 原子比为（1.12±0.17）∙10。估计沉积岩芯中人为铀沉降的全球沉降物和近域 PPG 沉降物的贡献分别约为 69%和 31%。我们认为人为铀在菲律宾沉积物中沉积的主要驱动过程是下沉颗粒不断从表层海水中吸萃溶解的 U。
