macro Tobacco Radioactivity


"Surgeon General's Warning: Smoking is Hazardous to Your Health"
macro Warning labels such as this appear on every package of cigarettes sold in Austria. The link between cigarette smoke and cancer has long been established. There is, however, another cancer-causing mechanism in smokers. The culprit in this case is a radioactive environmental pollutant present in the tobacco leaves from which cigarettes are made. 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 uranium-238 decay series:

226-Ra decays to 222-Rn + alpha rays

The product formed, radon-222, is an unreactive gas (radon is the only gaseous product in the uranium-238 decay series). Radon-222 emanates from radium-226 and is present at high concentrations in soil gas and in the surface air layer under the vegetation canopy provided by the field of growing tobacco (see plantation). In this layer some of the daughters of radon-222 such as polonium-218 and lead-214 become firmly attached to the surface and interior of tobacco leaves. As the table shows, the next few decay reactions leading to the formation of lead-210 proceeds rapidly. Gradually, the concentration of radioactive lead-210 can build to quite a high level.

During the combustion of a cigarette, small insoluble smoke particles are inhaled and deposited in the respiratory tract of the smoker and are eventually transported and stored at sites in the liver, spleen, and bone marrow. Measurements have shown that there is a high lead-210 content in the se particles. (Note that the lead-210 content is not high enough to be hazardous chemically, but because it is radioactive it is hazardous indeed). Because of its long half-life (20.4 years), lead-210 and its radioactive daughters, bismuth-210 and polonium-210, can continue to build up in the body throughout the period of smoking. Constant exposure of organs and bone marrow to alpha- and beta-particle radiation increases the probability of cancer development in the smoker. The overall damaging effect on a person is quite similar to that caused by radon gas exposure indoors of houses built in particular geographical areas.
Nicotine addiction is only part of the problem of tobacco use.

M.R. - 1994

addiction test   smoking and health