Anthropogenic radioactivity

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. Radiation wasusedas early as 1902 in the treatment of diseases, including enlarged thymus, tinea capitis, acne, and cancers of childhood and adolescence. The use of X-rays by physicians and dentists represents the largest source 

Production of power from nuclear reactors involves uranium mining, fuel fabrication, the reactor operations, and storage of wastes. All of these processes may expose humans and the environment to radiation. Uranium production in the United States was 12,300 tons of U3O8 in 1977, primarily from western states, Texas, and Florida. Mining from deep shafts or open pits is the preferred method of uranium extraction, although in Florida it is produced as 

The fission releases 1-3 neutrons and, if additional fissionable material is present in sufficient quantity and in the right configuration, a chain reaction occurs. Radionuclides formed per megaton of fission include fission products (89Sr, Sr, Zi, io3ru, i if, i37cs, and activation products in air ( H, 3 Ar) and soil ( Na, Fe, 

Fission-product radionuclides of potential biological importance include °Sr, Cs, 1311, 129l, 144cg 103Ry 106Ry 95 140gg  

Most of the world s supply of uranium consists of about 0.7% and 99% 

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Most of the estimates of aluminum uptake summarized above are based on the assumption that urinary excretion represents absorption, although a few values were determined using the anthropogenic radioactive isotope 26Al in combination with a sophisticated analytical technique (accelerator mass... 

Aside from accidents in nuclear facilities (e.g., Chernobyl), the main source of anthropogenic radioactive pollution is probably derived from medical applications. Documented reports of radioactive residue mismanagement indicate that sometimes these substances end up in garbage dumps, with the consequent danger of public exposure. The main radioactive isotopes in medical applications are listed in Table 8.7. 

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. 

Anthropogenic radioactive contamination of the marine environment has several sources disposal at sea, discharges to the sea, accidental releases and fallout from nuclear weapon tests and nuclear accidents. In addition, discharge of naturally occurring radioactive materials (NORM) from offshore oil and gas production is a considerable source for contamination. 

Compared to other wastes disposed of at sea the amount of radioactive waste by weight is rather diminutive. However, contrary to most of the ordinary wastes in the sea, detectable amounts of anthropogenic radioactivity are found in all parts of the world oceans and will continue to contaminate the sea for many thousands of years to come. This means that anthropogenic radioactive material has become an extra chronic radiation burden for marine organisms. In addition, the release of natural occurring radionuclides from offshore oil and gas production will gradually increase the levels of radium, in particular, with a possible, at present unknown, effect. 

This ice-flow model can be supplemented by certain other methods listed in Table 17.9. The application of methods based on natural or anthropogenic radioactive isotopes is limited because of low concentrations, irregular distribution, and because the basic assumptions of dating are not always satisfied. 

Ross Kleinschmidt (natural and anthropogenic radioactive matter in groundwater, surface water and sod). Radiation Nuclear Sciences, Forensic Scientific Services, Health Support Queensland Department of Health, Queensland Government, Coopers Plains, QLD... 

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