The hookah series part 1: total metal analysis in hookah tobacco (narghile, shisha) – an initial study

Abstract

In this initial study, the concentrations of eighteen elements (Na, K, Mg, Ca, Al, Fe, V, Cr, Mn, Ni, Cu, Zn, Se, Mo, As, Cd, Sb and Pb) in 12 hookah tobacco formulations (mo'assel) were studied by ICPMS. Eight of these were formulated in the United States, and four were from the Middle East. The analyses were made from two of the hookah compartments; as homogenized material of the hookah samples as received and by separating the received samples into the actual tobacco and a hot water extract that removed as much of the other formulation substances as possible. The extractable portion that represents up to 50% in mass of the total hookah sample is made up of honey/molasses, glycerin, colorants and flavorings, but this study shows the hot water extract to be relatively free of toxic elements. The elemental ranges found for the homogenized hookah mixtures are as follows: V, 0.03–0.16 μg g⁻¹; Cr, 0.15–0.37 μg g⁻¹; Mn 8.82–17.2 μg g⁻¹; Ni, 0.14–0.64 μg g⁻¹; Cu, 0.93–5.67 μg g⁻¹; Zn, 3.51–5.62 μg g⁻¹; As, 0.01–0.04 μg g⁻¹; Se, 0.002–0.014 μg g⁻¹; Mo, 0.05–0.13 μg g⁻¹; Cd, 0.10–0.27 μg g⁻¹ and Pb, <0.001–0.07 μg g⁻¹. Given the very small fraction of trace metals in the extract, most of the metals are contained in the tobacco leaves. It was found that the major variation in the concentrations owe to the geographic production regions; namely the USA and the Middle East. A principal component analysis was performed as an explorative tool, and a good separation was found, when grouping according to preparation by geographic production region. Based on these results the average mass of the more toxic elements (As, Cd, Cr and Pb) present in a hookah smoking portion of about 15 g, is smaller than that contained in a normal cigarette. However, before any true comparisons can be made on the differences between the hookah formulations and actual dryer tobaccos, the temperature at which the smoke is produced, the length of time per smoking session, any possible metal contamination from the apparatus and contamination from the charcoal used to ignite the hookah formulation must be taken into account.