ABSTRACT
Radioactivity denotes the process by which a radionuclide undergoes spontaneous disintegration (decay) of its unstable nucleus with the emission of one or more radiations and the formation of a daughter nuclide. Neutron particles can be generated naturally in the atmosphere via cosmic ray interaction, as well as anthropogenically during fission reactions in nuclear reactors and at sites of nuclear detonations. The emission of gamma rays commonly accompanies the release of alpha and beta particles during the decay of many radionuclides. In estuarine and coastal marine environments, a wide array of organisms accumulates radionuclides from various stages of the nuclear fuel cycle. Estuarine and marine environments, apart from being affected by anthropogenic sources of radioactivity, are unavoidably exposed to naturally occurring background radioactivity, which is measured in the International System of Units. The International Commission on Radiological Protection (ICRP) has developed basic guidelines of radiological protection applicable to better management of low-level radioactive waste disposal in the marine environment.
