Nuclear weapons fallout from

Plutonium (Pu) is an artificial element of atomic number 94 that has its main radioactive isotopes at 2 °Pu and Pu. The major sources of this element arise from the manufacture and detonation of nuclear weapons and from nuclear reactors. The fallout from detonations and discharges of nuclear waste are the major sources of plutonium contamination of the environment, where it is trapped in soils and plant or animal life. Since the contamination levels are generally very low, a sensitive technique is needed to estimate its concentration. However, not only the total amount can be estimated. Measurement of the isotope ratio provides information about its likely... 

Concentratons of Sr in people living in New York City between 1953 and 1959 who were exposed to nuclear weapons fallout were reported by Kulp and Schulert (1962). They suggested that the distribution of observed values was well fit by a log-normal distribution that had a geometric standard deviation of about 1.7. The Federal Radiation Council (FRC, 1961), after review of the accumulated data on Sr in human bone, concluded that a log-normal distribution was the appropriate description of the distribution of this age-controlled, exposuretime controlled population. The main exposure to Sr from fallout was by way of ingestion. 

The radiological impact of the Chernobyl debris compared with that from nuclear weapons fallout. Journal of Environmental Radioactivity, 6,151-62. Aarkrog, A. Lippert, J. (1971) Direct contamination of barley with 51 Cr,59Fe,58 Co, 65Zn, 203Hg and 210Pb. Radiation Botany, 11, 463-72. 

Phillips F. M., Mattick J. L., Duval T. A., Elmore D., and Kubik P. W. (1988) Chlorine-36 and tritium from nuclear weapons fallout as tracers for long-term liquid and vapor movement in desert soils. Water Resour. Res. 24, 1877-1891. 

Cesium-137 and strontium-90 from nuclear weapon fallout using tobacco as an example Z. Lebensm. 

Blanks of the swipe sample matrix ( swipe blank ) after each processing step. The swipe blank contains the process blank as well as any U, Pu or interfering elements contained in the swipe material. The cotton wipers chosen for swipe sampling are generally quite low in U content - 1-5 ng per wiper - and the Pu content is not measurable by bulk analysis it is believed to be below 1 fg (the most likely source would be Pu from nuclear weapons fallout). 

The background radiation to which we are all subjected has increased slightly since the advent of nuclear technology. Fallout from atmospheric testing of nuclear weapons increased this background by several percent, but it has decreased since atmospheric testing was banned. The radiation contributed by nuclear power plants is only a fraction of a percent of the natural background. 

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. 

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. 

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). 

Contamination of aquatic foodstuffs by the radiocerium in fallout from weapons tests and effluents from nuclear power facilities is well documented. The concentrations of 144Ce in clam muscle and cuttlefish in Japan in 1960 exceeded those of Sr by one to two orders of magnitude and were somewhat greater than those measured in food crops (Nezu et al., 1962). Radiocerium was detected in only a few samples of aquatic foods monitored in the Central Pacific during nuclear device testing there in 1962 (Welander and Palumbo, 1963 ... 

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. 

The 239j240pu can (je accounted for as being from nuclear weapons-produced fallout over the past 30 years, and not from the waste disposal canisters. The mechanism must be by transport and redistribution of the fine floculent sediment at the sediment-water interface. Because of the significant amount of sediment which is being transported down-canyon, any leakage from the canisters would probably be scavenged locally by the environmental sediment material. 

Figure 5.1 illustrates the primary threats based on the explosion of a 10-kiloton nuclear weapon. The distances are taken from Tables 5.1 and 5.2 and are intended to illustrate the impact such a weapon would have if detonated in a populated area. No specific fallout radius is provided because it depends on yield, location, and meteorological conditions and is very difficult to predict. 

Time and shielding can be merged into a single factor. The shelters described in Section 5.2.1 (walls, basements, etc.) really serve as shields from radiation, heat, fallout, and even from the air blast and flying debris. At the moment of explosion, radiation and heat travel at the speed of light and expose unshielded victims. At the instant of realization that a nuclear weapon has exploded, an individual should move as quickly as possible to a location behind a rugged shielding material. 

Alkali metals (K, Rb, Cs) behave similarly and sometimes one is accumulated preferentially when another is deficient. A similar case is made for Sr and Ca (Whicker and Schultz 1982a). The most important alkali metal isotope is Cs because of its long physical half-life (30 years) and its abnndance as a fission prodnct in fallout from nuclear weapons and in the inventory of a nuclear reactor or a fuel-reprocessing plant. Cesium behaves much like potassium. It is rapidly absorbed into the bloodstream and distribnted throughout the active tissues of the body, especially muscle. The P and y radiation from the decay of Cs and its daughter, Ba, result in essentially whole-body irradiation that harms bone marrow (Hobbs and McClellan 1986). 

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