Activity Levels of Polonium-210 in Tobacco and Cigarette in Iran

Polonium-210 (210Po) is a natural contaminant of tobacco and its products. Due to its volatility and inherent adsorption properties, 210Po is one of the major potential sources of human exposure through smoking. This paper reports measurements on 210Po and 210Pb levels in domestic as well as imported tobacco to Iran through α-spectrometry technique. The fate of 210Po radionuclide has been also followed from tobacco farm through curing procedure in factory. The activity levels of 210Po in Iranian domestic and imported cigarettes is found to be on the average as 38.4±0.8 mBq/g with a range of 30.3-51.3mBq/g and 20.0±0.6mBq/g with a range of 18.6-21.7mBq/g, respectively. These levels are considerably higher than those reported in many other parts of the world. In the case of tobacco produced in Iranian northern province of Guilan, drying in closed compartments by fossil fuel and elevated inventories of 210Po in soil due to over application of phosphate-rich fertilizers seems to be the main causes of these elevated activity levels.