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

 

Recent publications


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

2017 (15/5)
Geochimica et Cosmochimica Acta
vol.205 pp.168-186
(Article)
2016 (1/4)
Tobacco Regulatory Science
vol.2 pp.166-175
(Article)
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 
Keywords: Cigarette design, Metals, Policy
2015 (11)
Nicotine & Tobacco Research
vol.17 pp.1331-1336
(Article)
Design characteristics and tobacco metal concentrations in filtered cigars
Rosalie V. Caruso, Richard J. O'Connor, Mark J. Travers, Cristine D. Delnevo, Ed Stephens 
2015
vol.2015-0026 
(Commissioned report)
2015
vol.2015-0144 
(Commissioned report)
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 (1/11)
Tobacco Control
vol.24 pp.iv55-iv59
(Article)
2014 (11/12)
Tobacco Induced Diseases
vol.12 
(Article)
2014 (1/1)
Environmental Science and Technology
vol.48 pp.3449-3456
(Article)
Controls on the valence species of arsenic in tobacco smoke
Ed Stephens, Adrian Anthony Finch, K. Geraki 
2013 (20/12)
International Journal of Environmental Research and Public Health
vol.11 pp.202-217
(Article)
2010 (10)
Tobacco Control
vol.19 pp.-
(Article)
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 
Keywords: TOBACCO, EXPOSURE, SMOKE, NICOTINE, YIELDS, LESS, TAR
2009
Eos, Transactions, American Geophysical Union
vol.90 pp.1885
(Article)
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 
2009 (1/10)
Scottish Journal of Geology
vol.45 pp.117-130
(Article)
2008
Earth and Environmental Science Transactions Of The Royal Society Of Edinburgh
vol.99 pp.225-250
(Article)
2007 (3)
Earth and Environmental Science Transactions Of The Royal Society Of Edinburgh
vol.98 pp.59-69
(Article)
2006
Scottish Journal of Geology
vol.42 pp.137-148
(Article)
2005
Geological Society Special Publication
vol.248 pp.133-151
(Article)
2004
Geological Society of America: Special Papers
vol.389 pp.1-390
(Special issue)
Fifth Hutton Symposium on the origin of granites and related rocks
S. Ishihara, Ed Stephens, S.L. Harley, M. Arima, T. Nakajima 
2004
Teaching Earth Sciences
vol.29 pp.26-27
(Article)
Minerals and Health
Ed Stephens 
2004 (3)
Transactions of the Royal Society of Edinburgh: Earth Sciences
vol.95 pp.1-390
(Special issue)
Origin of granites and related rocks
S. Ishihara, Ed Stephens, S.L. Harley, M. Arima, T. Nakajima 
2004
Transactions of the Royal Society of Edinburgh: Earth Sciences
vol.95 pp.5-6
(Editorial)
2004
Geological Society of America: Special Papers
vol.389 pp.5-6
(Editorial)
2003
La Medicina de Lavaro
pp.64-65
(Article)
2003
Geochimica et Cosmochimica Acta
vol.67 pp.A448
(Article)
2003
Geochimica et Cosmochimica Acta
vol.47 pp.A448
(Article)
2003
Geochimica et Cosmochimica Acta
vol.68 pp.A530
(Article)
2003
Eos, Transactions, American Geophysical Union
vol.86 pp.314
(Article)
2003 (8)
Transactions of the Institution of Mining and Metallurgy, Section B-Applied Earth Science
vol.112 
(Article)
2001
Transactions of the Royal Society of Edinburgh: Earth Sciences
vol.91 pp.1-321
(Special issue)
Origin of Granites and Related Rocks
Bernard Barbarin, Ed Stephens, Bernard Bonin, Jean-Luc Bouchez, D.B. Clarke, M. Cuney, Martin H. 
2001
Transactions of the Royal Society of Edinburgh: Earth Sciences
vol.91 pp.v-vi
(Editorial)
Preface
B Barbarin, Ed Stephens 
Keywords: Geology
2001
Geological Society of America: Special Papers
vol.350 pp.v-vi
(Article)
Preface
Bernard Barbarin, Ed Stephens 
2000 (1)

(Book)
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 (5)
Journal of the Geological Society
vol.157 pp.601-613
(Article)
1999
vol.17 pp.409-412
(Chapter (peer-reviewed))
Glen More
Ed Stephens 
1999
Lithos
vol.46 pp.331-626
(Special issue)
Granites and Associated Mineralization
A.N. Sial, Ed Stephens, Ferreira V.P. 
1999
vol.46 pp.331
(Conference contribution)
1999
Anais da Academia Brasileira de Ciencias
vol.71 
(Article)
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 
Keywords: Hhp granite, Th-rich, portugalGeneral
1998
Acta Universitatis Carolinae - Geologica
pp.83-85
(Article)
1997

(Book)
Granite: from Segregation of Melt to Emplacement Fabrics
J.-L. Bouchez, D.H.W. Hutton, Ed Stephens 
1997 (27/3)
Chemical Geology
vol.136 pp.55-70
(Article)
1997
Journal of Petrology
vol.38 pp.169
(Book/Film/Article review)
1997 (5)
Transactions of the Institution of Mining and Metallurgy, Section B-Applied Earth Science
vol.106 
(Article)

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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research@st-andrews

School of Earth and Environmental Sciences

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