Nuclear bomb testing carbon

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. 

In his 1956 paper on radioactive fallout (7) Libby pointed out that neutrons released in the explosions of nuclear weapons react with nitrogen nuclei in the air to make carbon-14, which has a half-life of about 5600 years. In his discussion of bomb-test carbon-14 he said that Fortunately, this radioactivity is essentially safe because of its long lifetime and the enormous amount of diluting carbon dioxide in the atmosphere. He pointed out that 5.2 tons of neutrons would be needed to double the feeble natural radioactivity of living matter due to radiocarbon. Such an increase would have no significance from the standpoint of health. He mentioned that, for a given energy release, thermonuclear weapons produce more neutrons than fission weapons, and concluded that the essential point is that the atmosphere is difficult to activate and the activities produced are safe, ... 

Calcium phosphate is the component of human bone that provides rigidity. Fallout from a nuclear bomb can contain radioactive strontium-90. These two facts are closely tied together when one considers human health. Explain. Limestone consists mainly of the mineral calcite, which is calcium carbonate. A very similar deposit called dolostone is composed primarily of the mineral dolomite, an ionic substance that contains carbonate ions and a mixmre of magnesium and calcium ions, (a) Is this a surprising mixture of ions Explain, based on the periodic table, (b) A test for limestone is to apply cold dilute hydrochloric acid, which causes the rapid formation of bubbles. What causes these bubbles ... 

Variability in the Amount of Carbon in Reservoirs. In addition to variations in the production and distribution of radiocarbon over time and within portions of various carbon reservoirs, variations may result in situations where carbon not in equilibrium with the contemporary standard values is added or removed from any reservoir. Two instances of this are well documented since they occurred within the last century as a result of human intervention. The first is known as the industrial or Suess effect and is caused by the combustion of fossil fuels beginning about 1890, resulting in a depletion of atmospheric activities by about 3% (76). A more recent occurrence has been called the atomic bomb or Libby effect. The detonation of nuclear devices in the atmosphere beginning in 1945 produced large amounts of artificial increasing the radiocarbon concentrations in the atmosphere by more than 100% in the Northern Hemisphere (77). Because of equilibration with the oceans, the levels have been diminishing steadily since the atmospheric testing was terminated by the major nuclear powers except France and the People s Repub-... 

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