Radionuclides anthropogenic, sources

Many coastal ecosystems have elevated levels of metals and radionuclides (14). Anthropogenic sources of stable isotopes of metals include sewage disposal plants, electroplating plants, and mining and dredging operations sources of radioactive isotopes include effluents from nuclear power plants and submarines, medical establishments, and uranium ore mining. The pollution from most of these operations results from routine or accidental discharges and are either continuous or episodic. 

This new text addresses the major toxins and contaminants found in plant and animal products that constitute the staple diets of the world. In four parts part 1 addresses plant and microbial toxins part 2 deals with contaminants arising from anthropogenic sources part 3 addresses contemporary issues, including prion diseases, genetically modified foods, and radionuclides in foods and part 4 addresses ongoing concerns related to information from the earlier sections. 

In the analysis of a sarrqrle for its content of natural radioactivity it is necessart today to consider the possibility that the saitqrle has become contaminated by "non-rmtural" radioactivities, i.e. radionuclides added to by human activities (so-called anthropogenic sources). Nuclear weapons tests, nuclear satellites bumt-up in the atmosphere, and nuclear power accidents may release large amounts of activities, see Table 5.4. The nuclear power industry is permitted by health authorities to continually release small, controlled amounts of specified radionuclides into the atmosphere and into open waters. Tables 19.7 and 21.10. 

The major anthropogenic sources that have lead, or could potentially contribute, to the radionuclide contamination of the environment are the following (1) the testing and production of nuclear weapons (2) the normal activities of the nuclear power fuel cycle (3) the radioisotope production and research reactors and (4) the nuclear accidents. 

Nuclear explosions and nuclear power production are the major sources of anthropogenic activity in the environment. But radionuclide use in medicine, industry, agriculture, education, and production and transport, use, and disposal from these activities present opportunities for wastes to enter the environment (Whicker and Schultz 1982a Table 32.6). Radiation was used as early as... 

The third principal component of environmental radioactivity is that due to the activities of humans, the anthropogenic radionuclides. This group of nuclides includes the previously discussed cases of 3H and 14C along with the fission products and the transuranium elements. The primary sources of these nuclides are nuclear weapons tests and nuclear power plant accidents. These events and the gross nuclide releases associated with them are shown in Table 3.1. Except for 14C and... 

Holm, E. 1994. Source and distribution of anthropogenic radionuclides in marine environment. In E. Holm (ed.), Radioecology, pp. 63-83. Singapore, New Jersey, London, Hong Kong World Scientific. 

The anthropogenic radionuclides of most concern are those produced as fission products from nuclear weapons and nuclear reactors. The most devastating release from the latter source to date resulted from the April 26, 1986, explosion, partial meltdown of the reactor core, and breach of confinement structures by a power reactor at Chernobyl in the Ukraine. This disaster released 5 x 107 Ci of radionuclides from the site, which contaminated large areas of Soviet Ukraine and Byelorussia, as well as areas of Scandinavia, Italy, France, Poland, Turkey, and Greece. Radioactive fission products that are the same or similar to elements involved in life processes can be particularly hazardous. One of these is radioactive iodine, which tends to accumulate in the thyroid gland, which may develop cancer or otherwise be damaged as a result. Radioactive cesium exists as the Cs+ ion and is similar to sodium and potassium in its physiological behavior. Radioactive strontium forms the Sr2+ ion and substitutes for Ca2+, especially in bone. 

There are in principle two sources for anthropogenic radioactivity in rivers in Sweden, 1954-58 (20%) and 1961-62 (80%), and the Chernobyl accident, 1986. These events are quite distinct in time and by using isotopic ratios and radionuclide ratios the two sources can be distinguished from each other. China and France also conducted nuclear tests during 1960 -1980. 

Releases of radionuclides from the nuclear fuel-re-processing plants at Sellafield and Cap de la Hague have provided tracers for detailed studies of the circulations of the local environment into which they are released, namely the Irish Sea, English Channel, and North Sea, and for the larger-scale circulation processes of the North Atlantic and Arctic Oceans. These tracers have very different source functions for their introduction into the oceans compared to other widely used anthropogenic tracers, and in some cases compared to each other. The fact that they are released at point sources makes them highly specific tracers of several interesting processes in ocean circulation, but the nature of the releases has complicated their quantitative interpretation to some extent. 

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