Polonium 210 in Tobacco, Cigarette Smoke, and Selected Human Organs

Abstract

The polonium 210 in tobacco may be implicated in the origin of lung cancer. Speculation on this possibility prompted a study at the Northeastern Radiological Health Laboratory, Public Health Service, to determine the levels of polonium 210 in several brands of cigarettes. The levels of lead 210 and radium 226 were also measured to determine whether the polonium 210 was in equilibrium with these precursors or was present independently. Samples of human organs were also analyzed for polonium 210 content to determine whether a difference could be detected in the concentration of this radionuclide between smokers and nonsmokers. Polonium 210 and associated radionuclides lead 210 and bismuth 210 were found to be present in tobacco. Considerably smaller quantities of radium 226 were also found. Our tests indicated that lead 210 is deposited in the tobacco independently of radium 226 and its daughter bismuth 210. For the various brands tested, the activities of polonium 210 in the total cigarette were of about the same level, with one exception: the cellulose plus charcoal brand was 30 percent higher than the average of all brands. Because polonium 210 is volatile at the temperature of burning tobacco and sub-sequently is inhaled in the smoke, a smoking machine was devised for determining amounts inhaled from various brands. Values for polonium 210 in inhaled smoke ranged from 11 percent to 35.7 percent of that in the total cigarette. Average dosages to the lungs of a person smoking two packages of cigarettes per day were calculated to be far below the maximum permissible concentration for polonium 210 in air per person in the general population. The intake from a cellulose-filtered cigarette is 58.5 percent and from a filtered treated-tobacco cigarette, 45.1 percent of that from a nonfiltered cigarette. To determine the feasibility of studying the distribution of polonium 210 in selected tissues and organs of the human body, random specimens of lung, liver, kidney, heart, and psoas muscle were obtained from smokers and nonsmokers. Our tests indicated higher levels of polonium 210 in the organs of smokers.