Comprehensive survey of radionuclides in contemporary smokeless tobacco products

K Mcadam,H Kimpton,C Liu,A Porter,A Faizi,J Mcaughey,B Rodu,M Mola

doi:10.1186/s13065-017-0359-0

Abstract

There is considerable interest in the chemical composition of smokeless tobacco products (STPs), owing to health concerns associated with their use. Previous studies have documented levels of 210Po, 210Pb and uranium in STP samples. Here, the levels of 13 α-particle and 15 β-radiation emitting radionuclides have been measured in a broad and representative range of contemporary STPs commercially available in the United States and Sweden. For each radionuclide, the level of radioactivity and calculated mass per gram of STP are reported. The results indicate that, among 34 Swedish snus and 44 US STPs, a more complex radionuclide content exists than previously reported for these products. Of the 28 radionuclides examined, 13 were detected and quantified in one or more STPs. The most frequently identified radionuclides in these STPs were 40K, 14C, 210Po and 226Ra. Over half the STPs also contained 228Th, and an additional 8 radionuclides were identified in a small number of STPs. The presence of 14C, 3H and 230Th are reported in tobacco for the first time. The activity of β-emitters was much greater than those of α-emitters, and the β-emitter 40K was present in the STPs with both the greatest radioactivity and mass concentrations. Since the three radionuclides included in the FDA’s HPHC list were either not detected (235U), identified in only three of 78 samples (238U), and/or had activity levels over fifty times lower than that of 40K (210Po, 238U), there may be a rationale for reconsidering the radionuclides currently included in the FDA HPHC list, particularly with respect to 40K. Using a model of the physical and biological compartments which must be considered to estimate the exposure of STP users to radionuclides, we conclude that exposure from α-emitters may be minimal to STP users, but 40K in particular may expose the oral cavities of STP users to β-radiation. Although a more comprehensive picture of the radioisotope content of STPs has emerged from this study, epidemiological evidence suggests that the levels of radionuclides measured in this study appear unlikely to present significant risks to STP users.

Highlights

There has been considerable interest in recent years in the chemical composition of smokeless tobacco products (STPs), primarily based around health concerns associated with their use
Results only 210Pb, 210Po and uranium have been previously reported in STPs, many other radionuclides have been reported to be present in the tobacco plant and tobacco products [8]
The activities of the 28 radionuclides measured in contemporary Swedish snus and US STPs on a wwb are summarised in Tables 2, 3 and 4, with individual product activity values in Additional file 1: Tables S2–S4 and the corresponding mass of these radionuclides presented in Additional file 1: Tables S5– S7

Summary

Introduction

There has been considerable interest in recent years in the chemical composition of smokeless tobacco products (STPs), primarily based around health concerns associated with their use. Banned in the European Union, STPs are widely used in the United States, Sweden and Norway, and across large parts of Africa and Asia. The International Agency for Research on Cancer (IARC) has classified STPs collectively as Group 1 (known human carcinogens) [1]. These radionuclides have subsequently been identified by the FDA as “Harmful or Potentially Harmful Constituents” (HPHC) in tobacco products and tobacco smoke [5]. A recent revision to IARC’s consideration of STPs revised the summary list to 210Po and uranium [6]

Results

Discussion

Conclusion