Radionuclides in marine sediment

Most contaminants in the sea originate from land sources. Radionuclides in sea water are transported by sea currents. Marine sediment is a physical trap for pollutants that are introduced to the environment and play an important role in radiological studies. Radionuclides from seawater bound to particulates sink to the seabed. Their resuspension causes the reintroduction of pollutants to the water column. Remobilization and horizontal/vertical transport by various processes may occur. Long-lived radionuclides become buried in sub-surface sediment. Grain size sediment classification and sediment geochemical composition all play a significant role in the development of the radionuclide content of marine sediment. Atmospheric fallout from the Chernobyl and the Fukushima accidents, atmospheric nuclear weapon testing, releases from nuclear industry plants, river runoff, and to a lesser extent directed and submarine groundwater discharges are the major sources of radionuclides in the marine environment.