210Po and its precursor 210Pb in cigarette smoke contribute a significant radiation dose to the lungs of smokers. In this work, the concentration of 210Po was determined in 17 of the most frequently smoked cigarette brands in Italy. Samples of tobacco, fresh filters, ash, and post-smoking filters were analyzed; 210Po was determined by alpha spectrometry after its spontaneous deposition on a silver disk. To verify the radioactive equilibrium between 210Po and 210Pb, lead was determined in one tobacco sample by counting the beta activity of its decay product 210Bi with a gas flow proportional detector after separation. The results of the present study show 210Po concentrations ranged from 6.84 to 17.49 mBq per cigarette. Based on these results, smokers who smoke 20 cigarettes per day inhale, on average, 79.53 ± 28.65 mBq d−1 of 210Po and 210Pb each. The mean value of the annual committed effective dose for Italian smokers, calculated by applying the dose conversion factor for adults of 4.3 μSv Bq−1 for 210Po and 5.6 μSv Bq−1 for 210Pb, was estimated to be 124.8 and 162.6 μSv y−1 for 210Po and 210Pb, respectively. The lung dose from inhalation of cigarette smoke is much higher than the lung dose from inhalation of atmospheric 210Po and 210Pb.
* Institute of General Chemistry, Urbino University “Carlo Bo,” P.zza Rinascimento 6, 61029 Urbino, Italy.
For correspondence contact: Donatella Desideri, Institute of General Chemistry, Urbino University “Carlo Bo,” P.zza Rinascimento 6, 61029 Urbino, Italy, or email at email@example.com.
(Manuscript accepted 22 June 2006)