Zheng Jian, Yamada Masatoshi
Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, 3609 Isozaki-cho, Hitachinaka, Ibaraki, 311-1202 Japan.
Environ Sci Technol. 2006 Jul 1;40(13):4103-8. doi: 10.1021/es0601179.
We examined the vertical distributions of 239+240Pu activity and 240Pu/239Pu atom ratio in settling particles and quantified the particulate 239+240Pu fluxes in the water column in the western Northwest Pacific. Settling particle samples were collected using sediment traps. Plutonium isotopes were analyzed using a sector field high-resolution ICP-MS. To the best of our knowledge, this is the first time that both Pu activity and Pu isotope ratio data have been obtained for settling particles in the Pacific Ocean. The high (>0.18) 240Pu/239Pu atom ratios in settling particles indicate that plutonium from the Pacific Proving Grounds (PPG) source in the central Pacific is transported toward the western Northwest Pacific. Evidence indicates that Pu scavenging onto the settling particles is strongly dependent upon the bulk mass flux. The results suggest that advective lateral transport of dissolved Pu from the open ocean to the ocean margin and removal of Pu into the margin sediments by particle scavenging is a common phenomenon in the Pacific Ocean. Plutonium can be considered as a useful tracer to study the transport and fate of other contaminants that readily adsorb to particles in marine environments.
我们研究了西北太平洋西部沉降颗粒中239+240Pu活度和240Pu/239Pu原子比的垂直分布，并对水柱中的颗粒态239+240Pu通量进行了量化。沉降颗粒样品通过沉积物捕集器收集。钚同位素采用扇形场高分辨率电感耦合等离子体质谱仪进行分析。据我们所知，这是首次获得太平洋沉降颗粒的钚活度和钚同位素比值数据。沉降颗粒中高（>0.18）的240Pu/239Pu原子比表明，来自中太平洋太平洋试验场（PPG）源的钚被输送到西北太平洋西部。有证据表明，钚在沉降颗粒上的 scavenging 强烈依赖于总质量通量。结果表明，溶解态钚从开阔海洋向海洋边缘的平流侧向输运以及通过颗粒 scavenging 将钚去除到边缘沉积物中是太平洋的常见现象。钚可被视为研究海洋环境中其他易吸附在颗粒上的污染物的输运和归宿的有用示踪剂。
