Radioactivity in Tobacco

The soil in which tobacco is grown is heavily treated with phosphate fertilizers, which are rich in uranium and its decay products. Consider a particularly important step in the uianium-238 decay series  

In addition to BNCT, another promising treatment for brain tumors is brachytherapy using iodine-125. In brachytherapy, seeds containing are implanted directly into the tumor. As the radioisotope decays, y rays destroy the tumor cells. Careful implantation prevents the radiation from harming nearby healthy cells. 

Brachytherapy seeds (shown with a penny to illustrate their size). 

Breeder reactor, 878 Nuclear binding energy, 863 Nuclear transmutation, 860 Radioactivity, 860 

Critical mass, 876 Nuclear chain reaction, 876 Positron, 860 Thermonuclear reaction, 880 

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Runeckles, V.C. Natural radioactivity in tobacco and tobacco smoke Nature 191 (1961) 322-325. 

Scherer, G. and F. Adlkofer Radioactivity in tobacco and tobacco smoke CORESTA 1986 Symp., Taormina, Italy,... 

The radioactivity in tobacco leaves collected from 15 different regions of Greece was studied. The activities of radium, Ra and Ra, in the tobacco leaves reflect their origin from the soil by root uptake rather than from fertilizers used in the tobacco cultivation. Pb originates from the air and is deposited onto the tobacco leaves and trapped by the trichomes. 

Insects use camouflage coloration as a means of avoiding predation. The green color of the tobacco hornworm larvae, (Manduca sexta) can be separated into constituent blue and yellow components. The water soluble blue component is the biliprotein, insecticyanin. The yellow color is derived from lipoprotein bound carotenes. This lipoprotein, lipophorin, is the major lipid transport vehicle in insect hemolymph. In addition to transporting dietary lipid, lipophorin is also involved in the transport of lipophilic insecticides. Nearly all the recovered radioactivity in hemolymph from topically applied [14c] ddt is associated with lipophorin. Lipophorin of adult M. sexta is larger, less dense and is associated with small amounts of a third, adult specific, apoprotein. Alterations in adult lipophorin density, lipid content and apoprotein stoichiometry can be caused by injection of the decapeptide, adipokinetic hormone. 

Polonium was discovered in 1898 by Marie and Pierre Curie in their search for the sources of radioactivity in pitchblende. Polonium has 27 isotopes and is highly toxic and very radioactive. It has been suggested that the isotope 210Po, a natural contaminant of tobacco and an a-particle producer (see Section 21.1), might be at least partly responsible for the incidence of cancer in smokers. 

The presence of radioactivity, both a- and p-particles, in leaf and tobacco smoke has been reported in many publications. At earlier periods, the main concern was for P-activity found in cigars, cigarettes, and tobacco ash (113, 2657, 3367, 20A97). The a-emitting radioactive isotopes were suggested to be significant because of health concerns to smokers. The total a-activity in tobacco varies widely in green leaf, cured leaf tobacco, and tobacco smoke (2466, 3367, 3973). A very minor amount of °Po is transferred into the mainstream smoke (MSS). Twenty-four isotopes have been identified in tobacco smoke. The discovery of elements, isotopes, and ions in tobacco smoke has only been limited by the discovery and advancement of new analytical techniques. 

Biosynthetic methods are ideally suited for the synthesis of many radiolabeled compounds. Plants (e.g., potato and tobacco), when grown in the atmosphere of radioactive carbon dioxide utilize the as their sole source of carbon. After a suitable period of growth, almost every carbon atom in the plant is radioactive. In this way plants can serve as a source of labeled carbohydrates. Algae grown under similar conditions provide labeled amino acids, lipids, nucleotides, etc. Vitamin B12 is obtained from the metabolic products of microorganisms whose culture media contain cobalt-57 or cobalt-58. 

Radioactive decay schemes can be used to determine the ages of rocks and thereby the age of Earth (see Section 25-5). The appearance of certain radioactive substances in the environment can also be explained through radioactive decay series. The nuclides °Po and Pb have been detected in cigarette smoke. These radioactive isotopes are derived from found in trace amounts in the phosphate fertilizers used in tobacco fields. These a-emitting isotopes have been implicated in the link between cigarette smoking and cancer and heart disease. 

Since cigarette tobacco already contains several micrograms of the TSNA, we determined the transfer rate of NNN into the smoke by spiking the tobacco column with NNN-2 - C. The smoke from such radiolabeled cigarettes is then analyzed by HPLC and the amount of unchanged NNN-2 - C is determined by liquid scintillation counting. Independent of the smoke pH, about 11% of the radioactive NNN is found in the mainstream smoke thus 41-46% of mainstream smoke NNN stems from the tobacco NNN and 54-59% are pyrosynthesized (11). 

The observations made on effects of enviromnental agents on popnlations have been followed np in the laboratory. For example, if extracts of tobacco or coal tar are painted onto the skin of experimental animals, tnmors develop. Exposnre of experimental animals to X-rays or radioactive materials indnces tumor formation. 

Radon is another example of a very curious and toxic compound that many of us regularly inhale, hopefully in small amounts. For those regularly exposed to radon, there is an increased risk for lung cancer and, for those that smoke, radon exposure results in a three-fold increase in the incidence of lung cancer. In the United States it is estimated that indoor radon exposure causes between 7000 and 30,000 lung cancer-related deaths each year, second only to tobacco smoking. Radon-222 is a colorless and odorless radioactive gas that results from the decay of radium-226, which is widely distributed in the earth s crust. Radon decays with a half-life of 3.8 days into solid particles of polonium. It is actually the breakdown of... 

Burned tobacco contains some 4,800 distinct chemicals in either gas or particle phases. Many of the compounds in both phases are highly reactive, poisonous, and toxic. Harmful products include oxidants and poisons produced during burning, as well as radioactivity, heavy metals, and pesticides that may have accumulated within the tobacco leaf. Sixty-nine of these substances are known to cause cancer in humans and animals, and many others are known to be strong irritants. 

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