Landsberger S, Lara R, Landsberger S G
University of Texas, Nuclear Engineering Teaching Lab PRC, R-9000, Austin, TX 78712, USA Enviroklean Product Development, Inc., 9227 Thomasville Drive Houston Texas, Houston, TX 77064, USA
University of Texas, Nuclear Engineering Teaching Lab PRC, R-9000, Austin, TX 78712, USA.
Radiat Prot Dosimetry. 2015 Nov;167(1-3):243-6. doi: 10.1093/rpd/ncv254. Epub 2015 May 4.
The naturally occurring radionuclides of (235)U, (238)U and (232)Th and their daughter products are a potential major source of anthropogenic radiation to tobacco smokers. Often overlooked is the presence of (40)K in tobacco and its implication to radiation dose accumulation in the human body. In this study, these three radiation sources have been determined in four typical US cigarettes using neutron activation analysis (NAA). The NAA reactions of (238)U(n,γ)(239)U, (232)Th(n,γ)(233)Th and (41)K(n,γ)(42)K were used to determine (235)U, (238)U and (232)Th and (40)K, respectively. The activity of (238)U can easily be determined by epithermal NAA of the (238)U(n,γ)(239)U reaction, and the activity of (235, 234)U can easily be deduced. Using isotopic ratios, the activity due to (40)K was found by the determined concentrations of (41)K (also by epithermal neutrons) in the bulk material. Each gram of total potassium yields 30 Bq of (40)K. The annual effective dose for smokers using 20 cigarettes per day was calculate to be 14.6, 137 and 9 μSv y(-1) for (238,235,) (234)U, (232)Th and (40)K, respectively. These values are significantly lower that the dose received from (210)Po except for (232)Th.
天然存在的（235）U、（238）U和（232）Th放射性核素及其子产物是吸烟者人为辐射的一个潜在主要来源。烟草中（40）K的存在及其对人体辐射剂量积累的影响常常被忽视。在本研究中，使用中子活化分析（NAA）测定了四种典型美国香烟中的这三种辐射源。（238）U（n，γ）（239）U、（232）Th（n，γ）（233）Th和（41）K（n，γ）（42）K的NAA反应分别用于测定（235）U、（238）U和（232）Th以及（40）K。（238）U的活度可通过（238）U（n，γ）（239）U反应的超热中子活化分析轻松测定，（235，234）U的活度也可轻松推导得出。利用同位素比值，通过测定散装材料中（41）K（同样通过超热中子）的浓度来确定（40）K的活度。每克总钾产生30 Bq的（40）K。对于每天吸20支香烟的吸烟者，（238，235，）（234）U、（232）Th和（40）K的年有效剂量分别计算为14.6、137和9 μSv y⁻¹。除了（232）Th外，这些值显著低于从（210）Po获得的剂量。
