Nuclear bomb testing

There are also a number of less continuous but still natural net heat sources e.g. the heat released from volcanoes, earth quakes, and meteorites. There are also some anthropogenic sources form nuclear bomb tests, conventional bombs and explosives. 

A mass of evidence seems to confirm that the mixing rate of radiocarbon in the atmosphere is rapid, and that with respect to its radiocarbon content the atmosphere can be considered as a homogeneous entirety. The contamination of samples with matter from an extraneous source can nevertheless invalidate this assumption. Two types of contamination can be differentiated physicochemical contamination and mechanical intrusion. There are two forms of physicochemical contamination. One is due to the dilution of the concentration of radiocarbon in the atmosphere by very old carbon, practically depleted of radiocarbon, released by the combustion of fossil fuel, such as coal and oil. The other is by the contamination with radiocarbon produced by nuclear bomb tests during the 1950s and later in the twentieth century. The uncertainties introduced by these forms of contamination complicate the interpretation of data obtained by the radiocarbon dating method and restrict its accuracy and the effective time range of dating. 

The scope and scale of pollution from radionuclides has been greatly reduced due to (1) the cessation of aboveground nuclear bomb testing, (2) an international ban on the dumping of nuclear wastes at sea, and (3) better control of discharges from power and fuel reprocessing plants. 

The significance of radioactivity in water, food, and air has been under particular scrutiny since the advent of nuclear bomb tests and their accompanying radioactive fallout. This scrutiny has resulted in much documented data gathered over the past few decades on the health characteristics of man under various environmental conditions, such as the Denver populace who are subjected to more intense cosmic ray irradiations than the New York City populace the radium dial workers of the 1920,s who have provided data on life spans, general health, and causes of death population s drinking water with varying radium contents persons living... 

Most radioactive particles and vapours, once deposited, are held rather firmly on surfaces, but resuspension does occur. A radioactive particle may be blown off the surface, or, more probably, the fragment of soil or vegetation to which it is attached may become airborne. This occurs most readily where soils and vegetation are dry and friable. Most nuclear bomb tests and experimental dispersions of fissile material have taken place in arid regions, but there is also the possibility of resuspension from agricultural and urban land, as an aftermath of accidental dispersion. This is particularly relevant to plutonium and other actinide elements, which are very toxic, and are absorbed slowly from the lung, but are poorly absorbed from the digestive tract. Inhalation of resuspended activity may be the most important route of human uptake for actinide elements, whereas entry into food chains is critical for fission products such as strontium and caesium. 

An anthropogenic addition of 14C into the atmosphere occurred with the nuclear bomb testing from 1952 to 1963, along with the introduction of bomb tritium. As a result, the 14C concentration also increased in plants (Fig. 11.2), in the soil C02, and in recharged groundwater. Values up to 200 pmc have been measured, but they decreased to about 120 pmc by 1987, and to about 110 pmc by 1995. 

Sr90 29.1 y synovial joints By-product of nuclear bomb testing in the atmosphere in the 1940s to 1960s... 

Vertical profiles of Rn, Pb, Bi, and Po were measured over the mid-continental United States by Moore et al. (1973). These results for Rn and Pb are shown in Figure 3. A number of surface sites have been locations for long-term studies of Pb in conjunction with the measurements of radionuclides from nuclear bomb testing by the Environmental Measurements Laboratory of the Department of Energy and its precursor, the Atomic Energy Commission (Eeely et al., 1981). In addition, there have been measurements made throughout the United States and the islands of the Pacific and Atlantic as parts of the SEAREX and... 

Actinides in the environment can be classified into two groups (i) the uranium and thorium series of radionuclides in the natural environment and (ii) neptunium, plutonium, americium and curium which are formed in a nuclear reactor during the neutron bombardment of uranium through a series of neutron capture and radioactive decay reactions. Transuranics thus produced have been spread widely in the atmosphere, geosphere and aquatic environment on the earth, as a result of nuclear bomb tests in the atmosphere, and accidental release from nuclear facilities (Sakanoue, 1987). Most of these radionuclide inventories have deposited in the northern hemisphere following the tests conducted by the United States and the Soviet Union. 

Martin, J.M., Thomas, A.J., Charrier, B., Cousteau, J.Y. and Sarano, F Assessment of artificial radionuclides from French nuclear bomb testing at Mururoa (French Polynesia). Environ. Technol. Lett., 11 (3) (1990) 197-204. 

The global presence of radioactive fallout from the nuclear bomb tests of the 1950s and 1960s clearly illustrated the capacity of the atmosphere to distribute chemicals around Earth. Global transport has been demonstrated for a large number of chemicals that do not rapidly degrade or settle out of the atmosphere. Examples are methane (CH4), nitrous oxide (N20), and chloro-fluorocarbons (CFCs), all of which have half-lives in the atmosphere ranging from years to decades. 

Unintentional venting of an underground nuclear bomb test results in deposition of particles into the atmosphere at a height of 1.5 km over the site. If these soil particles have a density of 2.3 g/cm3, and the wind speed is 1.5 m/ sec, what would be the size of the particles that can be expected to fall predominantly outside the border of the test site, which is 200 km downwind ... 

Feely, H.W., and J.S. Spar, Tungsten-185 from nuclear bomb tests as a tracer for stratospheric meteorology. Nature 188, 1062, 1960. 

Konuma M Neuropsychiatric case-studies on the atomic bomb casualties at Hiroshima, in Research in the Effects and Influences of the Nuclear Bomb Test Explosions II. Tokyo, Japan Society for the Promotion of Science, 1956, pp 1715-1720... 

The pcrtechnctate ion will not likely be sorbed in significant amounts by soils and suspended bottom sediments of predominantly negative charge, but will be highly mobile in soils and waters and thus available for uptake in biota. The c level in soil down to a depth of 25 cm was estimated in 1979 to be 10 g/g of soil 18j. Tliis concentration was calculated from the known relative fission yield and the measured levels of Sr and Cs in soil, assuming that these fission products from nuclear bomb tests have nearly the same retention rates in soil. 

Figure 6. Atmospheric concentrations as functions of the radiogenic noble gases Ar, Kr, and Kr and of the man made traces gases CFC-11, CFC-12, and SFe. Concentrations are normalized to the respective atmospheric abundances in 1998. In addition a typical (input) curve of in precipitation is shown. Note, nuclear bomb tests in the atmosphere increased the global tritium inventory by up a factor of 1000. Since then concentrations steadily decreased, but still today tritium activity in young meteoric waters is commonly one order of magnitude larger than the natural background due to cosmic rays production.

During the past fifty years, cesium acquired a very bad reputation on the basis of two of its radioactive isotopes - both of which have a relatively long physical half-life - being distributed throughout the Earth s atmosphere following nuclear bomb tests and/or accidents at nuclear power plants, especially at Chernobyl (IAEA, 1986). 

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