CR3 News Magazine 2018 February: Black History Special Edition - Page 50

ISSN 1066-3622, Radiochemistry, 2016, Vol. 59, No. 2, pp. 208–214. © Pleiades Publishing, Inc., 2017. Published in Russian in Radiokhimiya, 2017, Vol. 59, No. 2, pp. 183–188. Lung Cancer Risks Due to the Radon in Cigarette Tobacco 1 A. A. Ridha* a and H. A. Hasan** b a Department of Physics, College of Science, Al-Mustansiriyah University, Baghdad, Iraq b Department of Medical Physics, College of Dentistry, Ibn Sina University of Medical and Pharmaceutical Sciences, Baghdad, Iraq e-mail: *dr.ali@uomustansiriyah.edu.iq, **hasn0010@yahoo.com Received June 27, 2016 Abstract—Thirty-one tobacco samples were evaluated for the activity concentrations of radon and radium using solid-state nuclear track detectors (CR-39). The detectors were exposed for a period of 150 days to differ- ent types of cigarette tobacco. The highest values of 364 Bq m –3 for radon and 31.4 Bq kg –1 for radium were obtained for MIA2 sample, and the lowest values of 20.2 Bq m –3 for radon and 1.74 Bq kg –1 for radium, for SUM sample. According to the estimate, this range of radon levels corresponds to the lung cancer incidence in the range 22–396 cases per million smoker per year. The annual effective dose in general and for lungs in par- ticular, the surface and mass exhalation rate, the equivalent equilibrium concentration of radon, and absorbed dose to tissues and lungs were calculated. The highest values were obtained for MIA2 sample, and the lowest values, for SUM sample. Keywords: radon, tobacco, effective dose, lung cancer risk, CR-39 detectors DOI: 10.1134/S1066362217020163 cutting, and manufacture into cigarettes. Lead-210 and polonium-210 can be absorbed into tobacco leaves directly from the soil or by absorbing radon from the air with the subsequent decay into 210 Pb and 210 Po. However, it is more important that fine sticky hairs (trichomes, Fig. 1) [4] on both sides of tobacco leaves grab airborne radioactive particles. According to the environment protection agency (EPA) estimates, radon is the number one cause of lung cancer among non- smokers and the second leading cause of lung cancer after cigarette smoke [5]. Many kinds of tobacco are grown in the world, with a variety of uses. The types of tobacco vary according to tobacco classes in various countries. The tobacco quality is influenced by nitrogen fertilization, plant density, topping time and height, and harvesting and curing procedures. A tobacco leaf contains a complex mixture of chemical components: cellulose products, starches, proteins, sugars, alkaloids, pectic substances, hydrocarbons, phenols, fatty acids, and inorganic min- erals [1]. It has been known for over 20 years that all types of tobacco contain radioactive 210 Po, which emits α-particles, and radioactive 210 Pb, which emits β-par- ticles and is a precursor of 210 Po. There is a degree of consensus about how tobacco becomes radioactive. Most soils contain radioactive elements such as ra- dium, which decays into 210 Pb and 210 Po. In addition, phosphate ore used as fertilizer in tobacco fields may contain such isotopes in relatively high concentrations. Thus, it was anticipated that tobacco plants can absorb 210 Pb and 210 Po through their roots. During tobacco processing, the radiation is not completely removed [2, 3]. The sticky compound that seeps from the trichomes is water-insoluble, and adhering particles are not washed off with the rain. They remain during curing, 1 Radon is responsible for about 21 000 lung cancer deaths every year. About 3000 of these deaths occur among people who never smoked. According to the World Health Organization (WHO) data, radon causes up to 15% of lung cancers worldwide [6]. Syed [7] studied whether the cigarette tobacco itself was a po- tential source of indoor radon and measured the levels of radon in tobacco samples of 15 different brands using CR-39 as a solid-state nuclear track detector (SSNTD). The results showed that the 222 Rn concentra- tion in cigarette tobacco samples ranged from 97 to 204 Bq m –3 . The levels of radon released from all investigated samples was significantly higher than the background level. The annual equivalent doses The text was submitted by the authors in English. 208