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Controls on the valence species of arsenic in tobacco smoke with implications for health and regulation

DOI: 10.1021/es4039243 DOI Help

Authors: Robert Campbell (University of St Andrews) , William Edryd Stephens (University of St Andrews) , Adrian Finch (University of St Andrews) , Tina Geraki (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Environmental Science & Technology , VOL 48 (6)

State: Published (Approved)
Published: February 2014
Diamond Proposal Number(s): 6601 , 7744

Abstract: Arsenic (As) is one of four metals/metalloids in tobacco being considered for regulation. In vitro toxicological response to As varies substantially, determined primarily by valence and compound speciation, and inorganic arsenite (As(III)) compounds are the most toxic to humans. This study uses X-ray absorption near edge structure (XANES) to determine valence states of As from the tobacco plant to the crucial combustion stage that creates respirable smoke. Samples studied include cultivated plants (some burdened with additional As), reference standards, and commercial products, along with smoke condensate and ash from these samples. The relative contributions of As(III) and As(V) to the XANES spectra are analyzed, and a consistent pattern of redox changes emerges. Tobacco leaf and manufactured products tend to be dominated by As(V) whereas combustion produces respirable smoke invariably in As(III) form and ash invariably as As(V). The valence state of precursor tobacco is not a controlling factor because all the As mobilized in smoke is reduced during combustion. This study concludes that tobacco combustion exposes smokers to potentially the most toxic forms of arsenic, and this exposure is magnified in regions where arsenic is present in tobacco crops at relatively high concentrations.

Subject Areas: Medicine

Instruments: I18-Microfocus Spectroscopy