in dry tobacco leaves in Greece

Tobacco leaves are large and have sticky exudates that retain the radon decay products once they deposit on the leaves. The study of Po in tobacco is required, because of the cumulative alpha-radiation dose delivered to humans from inhaled Po in cigarette smoke. Pb is the other element of interest since it is the Po precursor in the radioactive decay chain. In the present study, the concentrations of these two radionuclides were determined in tobacco samples from seven regions in Greece. Po was determined by alpha spectrometry using a surface barrier detector after radiochemical separation and spontaneous deposition of polonium on a nickel disk. The Pb activity in the samples was determined via the Po resulting from the decay of Pb. The results of the present study indicate that Po concentrations ranged from 3.6 to 17.0 mBq g 1 (average 13.1 mBq g ) of dry tobacco, while Pb concentrations ranged from 7.3 to 18.0 mBq g 1 (average 13.4 mBq g ). The mean value of the annual committed effective dose for smokers (20 cigarettes per day) of Greek tobacco was estimated to be 287 mSv (124 mSv from Po and 163 mSv from Pb). The inhalation dose for smokers is on average about 12 times higher than for non-smokers living in the mid-latitudes of the northern hemisphere. 2005 Elsevier Ltd. All rights reserved.