Nuclear weapons test fallout

The major source of plutonium in natural waters is the atmospheric fallout from nuclear weapons tests. Fallout plutonium is ubiquitous in marine and freshwater environments of the world with higher concentrations in the northern hemisphere where the bulk of nuclear weapons testing occurred(3). Much of the research on the aquatic chemistry of plutonium takes place in marine and freshwater systems where only fallout is present. 

Radioactive substances The principal sources of radionuclides released into the environment include nuclear weapon testing fallout from accidents such as the Chernobyl accident in 1986 or from foundering of nuclear submarines from the dumping of nuclear waste into the deep ocean and from discharges from nuclear power plants and nuclear reprocessing plants. 

Nuclear weapons testing fallout, which is characterized by a pulse-like injection into the atmosphere predominantly in the 1950s and 1960s, and includes the radioisotopes... 

The radiation hazard associated with fallout from nuclear weapons testing arises from radioactive isotopes such as these. One of the most dangerous is strontium-90. In the form of strontium carbonate, SrC03, it is incorporated into the bones of animals and human beings, where it remains far a lifetime. 

Atmospheric fallout from nuclear weapon tests and aquatic... 

Exposure of the general population to 241 Am via air, water, soil, and food are generally very low these background levels are a result of fallout from past atmospheric nuclear weapons tests. Since 1973, 241Am air concentrations have been less than 1 aCi/m3 (0.037 pBq/m3) and are continuing to decline (Bennett 1979). Levels around nuclear power plants are indistinguishable from fallout background (EPRI 1981). 

Denmark 1.5 days after the explosion. Air samples collected at Roskilde, Denmark on April 27-28, contained a mean air concentration of 241Am of 5.2 pBq/m3 (0.14 fCi/m3). In May 1986, the mean concentration was 11 pBq/m3 (0.30 fCi/m3) (Aarkrog 1988). Whereas debris from nuclear weapons testing is injected into the stratosphere, debris from Chernobyl was injected into the troposphere. As the mean residence time in the troposphere is 20-40 days, it would appear that the fallout would have decreased to very low levels by the end of 1986. However, from the levels of other radioactive elements, this was not the case. Sequential extraction studies were performed on aerosols collected in Lithuania after dust storms in September 1992 carried radioactive aerosols to the region from contaminated areas of the Ukraine and Belarus. The fraction distribution of241 Am in the aerosol samples was approximately (fraction, percent) organically-bound, 18% oxide-bound, 10% acid-soluble, 36% and residual, 32% (Lujaniene et al. 1999). Very little americium was found in the more readily extractable exchangeable and water soluble and specifically adsorbed fractions. 

Contamination of food crops by radiocerium in fallout from nuclear weapons tests has been extensively documented in the worldwide literature (Chhabra and Hukkoo, 1962 Merk, 1967 Michelson et al., 1962 Nezu et al., 1962 Sutton and Dwyer, 1964). The 144Ce concentrations in spinach leaves and radish roots in Japan in 1960 were within a factor of two of the respective "Sr concentrations (Nezu et al., 1962). 

Noyce, J. R., Moore, D. T., Sherwood, J. D., Daniel, P. R., Beck, J. N. and Kuroda, P. K. (1973). Fallout from nuclear weapons testing and interhemispheric transport of nuclear debris, Health Phys. 25, 109. 

Table II summarizes some of the features of the radioactive fallout processes in geophysical and astronomical settings. It seems that similarities do exist between the processes of formation of single particles from nuclear explosions and formation of the solar system from the debris of supernova explosion. We may be able to learn much more about the origin of the earth, by further investigating the process of radioactive fallout from the nuclear weapons tests.

The three test herds were exposed to different mixtures of local and world-wide fallout. When atmospheric nuclear weapons testing ceases, animals in the NTS herd reach a greater maximum in soft-tissue 137Cs concentration faster than animals in the other two herds (5). This is because the DV and KC herds respond primarily to world-wide fallout which... 

If there is fallout from nuclear weapons tests, or from reactor accidents, milk is likely to be the predominant source of 90Sr in diet, and an important source of 137Cs. A few days will intervene between an episode of fallout and the peak concentration in milk, giving time for preventative measures. It is therefore important to know the transfer factors, so that the future levels in milk can be predicted from the amount of fallout. The transfer depends on the retention of the fallout on the foliage, the amount of herbage eaten by the cattle, and the fraction of the cow s daily intake secreted per litre of milk. The transfer factor feed/milk is defined... 

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