Distribution and source of Pu in the sediments of the seas and estuaries of China—a review

Abstract

The coastal zone is the most concentrated area of human activities, and it is also the main accumulation zone of continental sediments, which is an ideal area for studying anthropocene sedimentary records. This study summarizes the distribution of ^239+240Pu activity, ^239+240Pu inventory, and ²⁴⁰Pu/²³⁹Pu atom ratios in the sediments of the seas and estuaries of China. Studies have shown that the distribution of ^239+240Pu activity in sediments is mainly influenced by sediment properties and ocean current dynamics. Furthermore, ^239+240Pu activity in sediment cores has obvious peak characteristics, which can be used in sediment dating. In fact, ²⁴⁰Pu/²³⁹Pu atom ratios indicate that the Pu in the sediments of the seas and estuaries of China mainly comes from global fallout and the Pacific Proving Grounds (PPG). Pu from the PPG enters the seas of China through the North Equatorial Current and Kuroshio intrusion current. And the contribution of Pu from the PPG in the East China Sea, the South China Sea, and the Yangtze estuary is over 40%. Moreover, Pu has been applied in the tracer of land-sea interactions and ocean dynamics, and it can be used as a background value to study the changes of Pu in the coastal zone of China in the future.