Sediment characteristics in the North Branch of the Yangtze Estuary based on radioisotope tracers

Nuclide-specific activity and sediment grain size were analyzed at locations along the North Branch of the Yangtze (Changjiang) Estuary. The spatial distributions of various radioisotopes are presented, along with the sources and applications of these nuclides for studies of the aquatic environment. The specific activities of sediment radionuclides in the North Branch increase toward the ocean, indicating that the sediment is transported from the downstream side of the estuary into the North Branch. The ²²⁶Ra/²²⁸Ra ratio agrees well with the observed results and can be used to identify trends in erosion and accretion in the North Branch.