The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
The Key Laboratory of Coastal and Island Development of Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China.
Chemosphere. 2018 Sep;207:130-138. doi: 10.1016/j.chemosphere.2018.05.082. Epub 2018 May 18.
Plutonium (Pu) isotopes were first determined in surface and core sediment samples collected from the northern North Yellow Sea (NYS) to elucidate their source terms and deposition process as well as the response to catchment environmental changes of inflow rivers. Pu/Pu atom ratios in all sediments showed the typical global fallout value of ∼0.18 without any influences from the nuclear weapons tests conducted recently in the North Korea or early in the Pacific Proving Ground. The large variation of Pu activities (0.022-0.515 mBq/g) observed in surface sediments should be mainly attributed to the re-suspension and transportation of fine sediments influenced by the Liaonan Costal Current. Based on the two Pu depth profiles with easily observed onset fallout levels (1952) and global fallout peaks (1963), Pu served as a valid time mark in the coastal sedimentary system. Riverine input Pu contributed only 15-27% to the total global fallout inventory (92.5-108.8 Bq/m) in the northern NYS, much lower than that in the Yangtze River estuary (77-80%), indicating a better soil conservation in the northeast China due to higher forest coverage compared to the Yangtze River's drainage basin. The increase of riverine input Pu after 1980s reflected the more intense soil erosion degree caused by the land use and cover change due to the increment of human activities in the northeast China at the same period. Our results demonstrated that plutonium is a good indicator for studying sedimentary process and its response to the environment in the coastal area.
钚（Pu）同位素首先在从北黄海（NYS）北部采集的表层和岩芯沉积物样本中确定，以阐明其来源和沉积过程，以及对流入河流流域环境变化的响应。所有沉积物中的 Pu/Pu 原子比均表现出典型的全球沉降值约为 0.18，不受朝鲜最近或太平洋试验场早期进行的核武器试验的影响。在表层沉积物中观察到的 Pu 活度（0.022-0.515 mBq/g）的较大变化主要归因于受辽南海流影响的细沉积物的再悬浮和运输。基于两个 Pu 深度剖面，很容易观察到起始沉降水平（1952 年）和全球沉降峰值（1963 年），Pu 作为沿海沉积系统中的有效时间标记。河流输入 Pu 仅占北 NYS 总全球沉降库存（92.5-108.8 Bq/m）的 15-27%，远低于长江河口（77-80%），这表明由于与长江流域相比，东北的森林覆盖率更高，土壤保持更好。20 世纪 80 年代后河流输入 Pu 的增加反映了由于同期东北人类活动的增加导致土地利用和覆盖变化引起的更严重的土壤侵蚀程度。我们的研究结果表明，钚是研究沿海地区沉积过程及其对环境响应的良好指标。
