April 1, 2011
Units: 37 GBq = 37×10^9Bq = 1 Curie
Radioactivity of Pb(210) and Po(210)
Lead 210, 22.3 years, 207.2 g/mol… Q = 0.064 MeV (beta)
Polonium, 137.376 days, 210 g/mol… Q = 5.407 MeV (alpha)
Let’s assume the amount of lead and Po to be 0.5 micro-gram each in 1 cigarette.
(0.5/207.2)x10^(-6) mol of Pb
(0.5/210)x10^(-6) mol of Po.
1 mol = 6.022×10^(23) “elements”
Implies 6.022×10^(17)x0.5/207.2 nuclei of of Pb = 1.45×10^15/cigarette
Implies 6.022×10^(17)x0.5/210 nuclei of Po = 1.43×10^15/cigarette
= 1.43×10^6 decays/second = 1.43MBq
= 0.00143/37 Curies = 38.65 microCurie
= 8.35×10^7 decays/second = 83.5MBq
= 0.0835/37 Curies = 2.26 milliCuries
SO the beta energy of the Pb(210) makes it
1.43(MBq)x0.064MeV = 91.52GeV
= 91.52×10^(9)x1.6×10^(-19)J = 14.64 nanoJ/cigarette.
Or 14.64 nanoGray/cigarette.
(Considering 1Kg of absorbing material)
Considering 20 cigarettes a day (a pack) and
regular smoking through a year this would be
(Lung has a weighing factor of 0.12 and Beta emission has a weighing factor of 1)
SO Po(210) with alpha emission would be
83.5(MBq)x5.407MeV which is actually 4.51×10^5GeV
=4.51×10^(14)x1.6×10^(-19)J = 72.2microJ/cigarette.
Or 72.2 microGray/cigarette.
SO with a pack of 20 cigarettes and 365 days of smoking one would collect a dose of
20x365x8.664microSv = 63.247 milliSv/year
(Again considering 1Kg of absorbing material, lung’s radiation damage factor and a simple alpha emission effect not considering alpha emission nuclear recoil. Also I have not multiplied the factor 20 for Alpha-particles which is done since I already calculated the energy I am not sure its necessary or not. In any case it’s dangerous enough. Po is more dangerous than Pb for lung cancer)
If the cigarette would indeed contain 0.5 microgram of Pb and Po, which is not known a priori, the values from experiment performed, 2 examples shown below shows different value, which just means the cigarettes contain correspondingly different radioactive contents, nonetheless harmful enough to kill smokers by lung cancer.
Since from the experiments of “Khater” and “Papastefanou” below, we have an annual dose of 100 microSv on an average for radio-active Pb as well as Po, it just means that we have more than 0.5 microgram of Pb but less than 0.5 microgram of Po in a single cigarette. Po is highly radio-active (Po-210 has a much smaller half-life) and emits alpha-rays, therefore much more dangerous than Pb-210.
References: (only the abstract available to me)
Ashraf E. M. Khaterl , mailto:firstname.lastname@example.org
National Center for Nuclear Safety and Radiation Control, Atomic Energy Authority, P.O. Box 7551, Nasr City, Cairo 11762, Egypt
Available online 3 October 2003.
“Due to the relatively high activity concentrations of 210Po and 210Pb that are found in tobacco and its products, cigarette smoking highly increases the internal intake of both radionuclides and their concentrations in the lung tissues. …(partially removed the abstract content)…. The results of this work indicate that the average (range) activity concentration of 210Po in cigarette tobacco was 16.6 (9.7–22.5) mBq/cigarette. The average percentages of 210Po content in fresh tobacco plus wrapping paper that were recovered by post-smoking filters, ash and smoke were 4.6, 20.7 and 74.7, respectively. Cigarette smokers, who are smoking one pack (20 cigarettes) per day, are inhaling on average 123 mBq/d of 210Po and 210Pb each. The annual effective doses were calculated on the basis of 210Po and 210Pb intake with the cigarette smoke. The mean values of the annual effective dose for smokers (one pack per day) were estimated to be 193 and 251 μSv from 210Po and 210Pb, respectively.”
Radiation dose from cigarette tobacco
Aristotle University of Thessaloniki, Atomic and Nuclear Physics Laboratory, Thessaloniki 54124, Greece
Corresponding author: email@example.com
Received September 12, 2005.
Accepted October 24, 2005.
“The radioactivity in tobacco leaves collected from 15 different regions of Greece before cigarette production was studied in order to estimate the effective dose from cigarette tobacco due to the naturally occurring primordial radionuclides, such as 226Ra and 210Pb of the uranium series and 228Ra of the thorium series and or man-made radionuclides, such as 137Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the annual effective dose due to inhalation for adults (smokers) for 226Ra varied from 42.5 to 178.6 μSv y−1 (average 79.7 μSv y−1), while for 228Ra from 19.3 to 116.0 μSv y−1 (average 67.1 μSv y−1) and for 210Pb from 47.0 to 134.9 μSv y−1 (average 104.7 μSv y−1), that is the same order of magnitude for each radionuclide. The sum of the effective doses of the three natural radionuclides varied from 151.9 to 401.3 μSv y−1 (average 251.5 μSv y−1). The annual effective dose from 137Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv y−1 (average 199.3 nSv y−1). “