Dr Ed Stephens

Dr Ed Stephens
Senior Research Fellow


 

Smoke efficiently delivers to the lungs of smokers and bystanders significant quantities of environmental metals that have accumulated in the tobacco plant or adhered to its leaves. My research focuses on the transfer mechanisms and the speciation of metals in the pathway “from seedbed to sickbed”. In this research I am applying the toolbox of geochemistry including ICPMS, XRF, XRD, EPMA, IRMS (all available in house) and XANES (Diamond synchrotron). This research involves characterising the valence and molecular species of metals in tobacco that may change slowly (e.g. curing process) or rapidly (combustion). Species determines the human bioavailability and detoxification pathways of the metal and is thus a key factor in toxicity and health risk.

As well as modelling pathways I have compiled global-scale datasets of compositional characteristics in the tobacco products of both trans-national and local producers. Somewhat fortuitously we found that application of chemometrics to these datasets revealed provincial patterns that we have since used to authenticate and provenance tobacco products in ways that are useful in controlling the distribution of illicit tobacco products. The illicit tobacco problem is colossal with about $50 billion lost in tax revenues each year while the availability of cheap illicit products discourages many smokers from quitting and facilitates many under age in taking up the habit. If there is no substantial reduction in current smoking prevalence then the WHO estimates that the tobacco epidemic will claim one billion lives in the 21st century.

Vaping is widely considered a helpful alternative for smokers who wish to quit and avoid exposure to the high levels of toxins associated with tobacco smoke. Metals are included among a small number of toxins in e-vapour for which there is still some concern over their safety. My research is directed at understanding the chemical processes involved in the creation of these toxins and their transport by vapour, the overall aim being to identify and quantify the risks to vapers' health. A methodology for comparing the cancer potency of aerosols generated by vapourising nicotine from non-tobacco sources with tobacco smoke was recently published (Stephens 2017b).

Recent publications

Stephens, W.E. (2017b) Comparing the cancer potencies of emissions from vapourised nicotine product sincluding e-cigarettes with those of tobacco smoke. Tobacco Control (on-line first) http://hdl.handle.net/10023/11421)

Stephens, W.E. (2017a) Chemometric and trace element profiling methodologies for authenticating, crossmatching and constraining the provenance of illicit tobacco products. Tobacco Control 26: 502-508

Yang J, Barling J, Siebert C, Fietzke J, Stephens WE, Halliday AN (2017). The molybdenum isotopic compositions of I-, S- and A-type granitic suites. Geochimica et Cosmochimica Acta. 2017;205:168-86.

Caruso RV, Fix BV, Thrasher JF, Cummings KM, Fong GT, Stephens WE, et al. (2016) Differences in Cigarette Design and Metal Content across Five Countries: Results from the International Tobacco Control (ITC) Project. Tobacco Regulatory Science. 2016;2:166-75.

Visser W, Geraets L, Klerx W, Hernandez L, Stephens WE, Croes E, et al. (2015) The health risks of using e-cigarettes. RIVM Letters: 2015-0144:47pp.

O’Connor RJ, Schneller LM, Caruso RV, Stephens WE, Li Q, Yuan J, et al.(2015) Toxic metal and nicotine content of cigarettes sold in China, 2009 and 2012. Tobacco Control. 24:iv55-iv9.

Campbell, R.J.C., Klerx, W., Talhout, R. and Stephens, W.E. (2015) Speciation of Metals and Metalloids in Tobacco and Tobacco Smoke Implications for Health and Regulation. RIVM Letters 2015-0026 (http://rivm.openrepository.com/rivm/handle/10029/557149)

Caruso RV, O’Connor RJ, Travers MJ, Delnevo CD, Stephens WE. (2015) Design Characteristics and Tobacco Metal Concentrations in Filtered Cigars. Nicotine & Tobacco Research. 2015;17(11):1331-6.

Campbell, R.C.J., Stephens, W.E. and Meharg, A.A. (2014) Consistency of arsenic speciation in global tobacco products with implications for health and regulation. Tobacco Induced Diseases 12:24 (doi:10.1186/s12971-014-0024-5)

Campbell, R.C.J. Stephens, W.E. and Finch, A.A. (2014) Controls on the Valence Species of Arsenic in Tobacco Smoke: XANES Investigation with Implications for Health and Regulation. Environmental Science and Technology 48, 3449−3456. (dx.doi.org/10.1021/es4039243)

Caruso, R.V., Connor, R.J., Stephens, W.E., Cummings, K.M. and Fong, G.T. (2014). Toxic Metal Concentrations in Cigarettes Obtained from U.S. Smokers in 2009: Results from the International Tobacco Control (ITC) United States Survey Cohort. Int. J. Environ. Res. Public Health 11, 202-217; (doi:10.3390/ijerph110100202)

source: symbiosis

 

50 (of 80 published available) for wes (source: University of St Andrews PURE)
Please click title of any item for full details

The molybdenum isotopic compositions of I-, S- and A- type granitic suites Jie Yang, Jane Barling, Christopher Siebert, Jan Fietzke, Ed Stephens, Alex N. Halliday
Geochimica et Cosmochimica Acta 2017 vol.205 pp.168-186
Differences in cigarette design and metal content across five countries Roselie V. Caruso, Brian V. Fix, James F. Thrasher, Michael K. Cummings, Geoffrey T. Fong, Ed Stephens, Richard J. O'Connor
Tobacco Regulatory Science 2016 vol.2 pp.166-175
Design characteristics and tobacco metal concentrations in filtered cigars Rosalie V. Caruso, Richard J. O'Connor, Mark J. Travers, Cristine D. Delnevo, Ed Stephens
Nicotine & Tobacco Research 2015 vol.17 pp.1331-1336
The health risks of using e-cigarettes W. Visser, L. Geraets, W. Klerx, L. Hernandez, Ed Stephens, E. Croes, P. Schwillens, H. Cremers, Bos P., R. Talhout
2015 vol.2015-0144
Toxic metal and nicotine content of cigarettes sold in China, 2009 and 2012 Richard J. O'Connor, Liane M. Schneller, Rosalie V. Caruso, Ed Stephens, Qiang Li, Jiang Yuan, Geoffrey T. Fong
Tobacco Control 2015 vol.24 pp.iv55-iv59
Controls on the valence species of arsenic in tobacco smoke Ed Stephens, Adrian Anthony Finch, K. Geraki
Environmental Science and Technology 2014 vol.48 pp.3449-3456
Toxic metal concentrations in cigarettes obtained from U.S. smokers in 2009 Rosalie V. Caruso, Richard J. O'Connor, Ed Stephens, K. Michael Cummings, Geoffrey T. Fong
International Journal of Environmental Research and Public Health 2013 vol.11 pp.202-217
Cigarettes sold in China: design, emissions and metals Richard J. O'Connor, Qiang Li, Ed Stephens, David Hammond, Tara Elton-Marshall, K. Michael Cummings, Gary A. Giovino, Geoffrey T. Fong
Tobacco Control 2010 vol.19 pp.-
Environmental pollen trapped by tobacco leaf as indicators of the provenance of counterfeit cigarette products Margaret Patricia Donaldson, Ed Stephens
JOURNAL OF FORENSIC SCIENCES 2010 vol.55 pp.738-741
Age and origin of the Amirante ridge ‐ trench structure, western Indian Ocean Ed Stephens, M. Storey, C.H. Donaldson, R.M. Ellam, E. Lelikov, G. Tararin, C. Garbe-Schoenberg
Eos, Transactions, American Geophysical Union 2009 vol.90 pp.1885
The Cluanie granodiorite, NW Highlands of Scotland I. Neill, Ed Stephens
Scottish Journal of Geology 2009 vol.45 pp.117-130
A reactive assimilation model for regional-scale cordierite-bearing granitoids J-M Ugidos, Ed Stephens, A. Carnicero, R M Ellam
Earth and Environmental Science Transactions Of The Royal Society Of Edinburgh 2008 vol.99 pp.225-250
A long record of environmental change from bat guano deposits in Makangit Cave, Palawan, Philippines Michael Ian Bird, Ella M. Boobyer, Charlotte Bryant, Helen A. Lewis, Victor Paz, Ed Stephens
Earth and Environmental Science Transactions Of The Royal Society Of Edinburgh 2007 vol.98 pp.59-69
Sediment provenance in the River Eden catchment, Scotland, using chemical characterization of Fe-Ti oxide minerals and magnetic measurements E Martinez-Monasterio, Robert William Duck, Ed Stephens, John Walden
Scottish Journal of Geology 2006 vol.42 pp.137-148
Terrane and basement discrimination in northern Britain using sulphur isotopes and mineralogy of ore deposits D Lowry, A J Boyce, Anthony Edward Fallick, Ed Stephens, N V Grassineau
Geological Society Special Publication 2005 vol.248 pp.133-151
Fifth Hutton Symposium on the origin of granites and related rocks S. Ishihara, Ed Stephens, S.L. Harley, M. Arima, T. Nakajima
Geological Society of America: Special Papers 2004 vol.389 pp.1-390
Minerals and Health Ed Stephens
Teaching Earth Sciences 2004 vol.29 pp.26-27
Origin of granites and related rocks S. Ishihara, Ed Stephens, S.L. Harley, M. Arima, T. Nakajima
Transactions of the Royal Society of Edinburgh: Earth Sciences 2004 vol.95 pp.1-390
Preface Ed Stephens, S L Harley
Transactions of the Royal Society of Edinburgh: Earth Sciences 2004 vol.95 pp.5-6
Special Paper of the Geological Society of America Ed Stephens, S L Harley
Geological Society of America: Special Papers 2004 vol.389 pp.5-6
Identification of quartz and other minerals in cigarettes Ed Stephens
La Medicina de Lavaro 2003 pp.64-65
Inorganic composition of tobacco: Sources and behaviour on combustion Ed Stephens, A. Calder
Geochimica et Cosmochimica Acta 2003 vol.67 pp.A448
Inorganic geochemistry and mineralogy of tobacco: Changes on combustion with health implications Ed Stephens, A. Calder
Geochimica et Cosmochimica Acta 2003 vol.47 pp.A448
Is the geological history of quartz a key factor in silica-related disease? Ed Stephens
Geochimica et Cosmochimica Acta 2003 vol.68 pp.A530
Minerals, tobacco and smoking-related disease Ed Stephens
Eos, Transactions, American Geophysical Union 2003 vol.86 pp.314
Sulphur isotope signatures of Neoproterozoic and Palaeozoic terrains of Northern Britain-environments of formation D LOWRY, A J Boyce, Anthony Edward Fallick, Ed Stephens, Ailsa Jane Hall, N V Grassineau
Transactions of the Institution of Mining and Metallurgy, Section B-Applied Earth Science 2003 vol.112
Origin of Granites and Related Rocks Bernard Barbarin, Ed Stephens, Bernard Bonin, Jean-Luc Bouchez, D.B. Clarke, M. Cuney, Martin H.
Transactions of the Royal Society of Edinburgh: Earth Sciences 2001 vol.91 pp.1-321
Preface B Barbarin, Ed Stephens
Transactions of the Royal Society of Edinburgh: Earth Sciences 2001 vol.91 pp.v-vi
Preface Bernard Barbarin, Ed Stephens
Geological Society of America: Special Papers 2001 vol.350 pp.v-vi
The Fourth Hutton Symposium on the Origin of Granites and Related Rocks B. Barbarin, Ed Stephens, B. Bonin, J.-L. Bouchez, D.B. Clarke, M. Cuney, H. Martin
2000
Weathering and abrasion of Fe-Ti oxides during rock degradation and fluvial transport E Martinez-Monasterio, Ed Stephens, John Walden, Robert William Duck
Journal of the Geological Society 2000 vol.157 pp.601-613
Glen More Ed Stephens
1999 vol.17 pp.409-412
Granites and Associated Mineralization A.N. Sial, Ed Stephens, Ferreira V.P.
Lithos 1999 vol.46 pp.331-626
The SÃo Pedro do Sul Granite (Central Portugal) L. J.P.F. Neves, Ed Stephens, A. J.S.C. Pereira, M M GODINHO, Anthony Edward Fallick
Anais da Academia Brasileira de Ciencias 1999 vol.71
Scorzalite-bearing granitic rocks of the Pedrógão Grande pluton (Central Portugal): Mineralogical and geochemical characterization LJPF Neves, LCG Pereira, AJSC Pereira, Ed Stephens, MM Godinho
Acta Universitatis Carolinae - Geologica 1998 pp.83-85
Characterization of multiple fluid-granite interaction processes in the episyenites of Avila-Béjar, Central Iberian Massif, Spain C Recio, Anthony Edward Fallick, J-M Ugidos, Ed Stephens
Chemical Geology 1997 vol.143 pp.127-144
Granite: from Segregation of Melt to Emplacement Fabrics J.-L. Bouchez, D.H.W. Hutton, Ed Stephens
1997
Provenance of Upper Precambrian-Lower Cambrian shales in the Central Iberian Zone, Spain J-M Ugidos, M. I. Valladares, C Recio, Ed Stephens, Anthony Edward Fallick
Chemical Geology 1997 vol.136 pp.55-70
Review of "Igneous Petrology" by A.M.Hall Ed Stephens
Journal of Petrology 1997 vol.38 pp.169
Sources of sulphur, metals and fluids in granitoid-related mineralization of the Southern Uplands, Scotland D Lowry, A J BOYCE, Anthony Edward Fallick, Ed Stephens
Transactions of the Institution of Mining and Metallurgy, Section B-Applied Earth Science 1997 vol.106

Contact Details:

Dr Ed Stephens
Bute Building
University of St Andrews
St Andrews
KY16 9TS
Fife
UK

tel: +44 01334 463947
fax: +44 01334 463949
room: C17
email: wes@st-andrews.ac.uk

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