Applications of Short-Lived Radionuclides (7Be, 210Pb, 210Po, 137Cs and 234Th) to Trace the Sources, Transport Pathways and Deposition of Particles/Sediments in Rivers, Estuaries and Coasts

Natural and anthropogenic radioisotopes can be used to determine not only the mixing and diffusion processes of water masses but also the sources and sedimentary dynamics of particles in aquatic systems such as rivers, estuaries and oceans. Particle-reactive radionuclides that are derived from atmospheric deposition and/or the decay from their parent nuclides in aqueous system, can be used to determine the removal rates of suspended particulate matter, sediment focusing/erosion, sediment resuspension rates and sediment accumulation and mixing rates. They can be also used as analogs for tracing the transport and fates of other particle-reactive contaminants, such as PCBs and PAH. In this chapter, we focus on various applications of short-lived radionuclides (i.e., ⁷Be, ²¹⁰Pb, ²¹⁰Po, ¹³⁷Cs and ²³⁴Th) as tracers for particle and sediment dynamics to quantify several river, estuary and coastal oceanic processes with their concerned timescales ranging from a few days to about 100 years.