Measurements of dermal uptake of nicotine directly from air and clothing

Abstract

In this preliminary study, we have investigated whether dermal uptake of nicotine directly from air or indirectly from clothing can be a meaningful exposure pathway. Two participants wearing only shorts and a third participant wearing clean cotton clothes were exposed to environmental tobacco smoke (ETS), generated by mechanically “smoking” cigarettes, for three hours in a chamber while breathing clean air from head-enveloping hoods. The average nicotine concentration (420 μg/m3) was comparable to the highest levels reported for smoking sections of pubs. Urine samples were collected immediately before exposure and 60 hour post-exposure for bare-skinned participants. For the clothed participant, post-exposure urine samples were collected for 24 hour. This participant then entered the chamber for another three-hour exposure wearing a hood and clothes, including a shirt that had been exposed for five days to elevated nicotine levels. The urine samples were analyzed for nicotine and two metabolites—cotinine and 3OH-cotinine. Peak urinary cotinine and 3OH-cotinine concentrations for the bare-skinned participants were comparable to levels measured among non-smokers in hospitality environments before smoking bans. The amount of dermally absorbed nicotine for each bare-skinned participant was conservatively estimated at 570 μg, but may have been larger. For the participant wearing clean clothes, uptake was ~20 μg, and while wearing a shirt previously exposed to nicotine, uptake was ~80 μg. This study demonstrates meaningful dermal uptake of nicotine directly from air or from nicotine-exposed clothes. The findings are especially relevant for children in homes with smoking or vaping

Dermal uptake of nicotine from air and clothing: Experimental verification

“…Peak concentrations in the 12‐ or 24‐hour pooled urine samples of the bare‐skinned participants (between 10 and 85 ng/mL, data not shown) were similar to those of the 2 bare‐skinned participants in Bekö et al and comparable to levels measured among non‐smokers in hospitality environments before the smoking ban. Peak concentration in the individual urine samples was slightly higher (nicotine: 102 ng/mL [P3], 89 ng/mL [P4]; cotinine: 71 ng/mL [P3], 38 ng/mL [P4]; 3OH‐cotinine: 123 ng/mL [P3], 68 ng/mL [P4]), approaching levels measured in light smokers .…”

“…S4). Urine samples were analyzed for nicotine and 2 of its metabolites, cotinine and 3‐hydroxycotinine (including their conjugates after enzymatic hydrolyzes) via LC‐MS with isotope dilution quantification, as described in Bekö et al The limits of quantification for nicotine, cotinine, and 3‐hydroxycotinine were 0.10, 0.05, and 0.12 μg/L, respectively.…”

“…We estimated the amount of nicotine absorbed by assuming that 90% of nicotine and its metabolites are excreted via urine and that the 3 metabolites and their conjugates constitute 85% of metabolites excreted in urine . We then subtracted the amount of nicotine inhaled from hood air (IU), calculated by the following equation: where BR is the breathing rate (0.7 m 3 /h), C air is the average air concentration in the hood (3.7 μg/m 3 ), f is the fraction of inhaled nicotine that is absorbed (0.7; see Bekö et al for details), and t is the exposure time (5 hours).…”

“…Morrison et al showed that clean clothing can impede, while clothing that has previously absorbed/adsorbed indoor air pollutants can increase dermal uptake. We have recently demonstrated dermal uptake of airborne nicotine directly from air or from exposed clothing . The air‐to‐skin‐to‐blood pathway may also be relevant with regard to thirdhand smoke, which can be associated not only with indoor surfaces but also skin and clothes .…”

“…The preliminary study of nicotine absorption from air by Bekö et al was performed on 2 bare‐skinned and 1 clothed participant. Daily pooled urine samples were collected over 60 hours after a 3‐hour exposure in a climate chamber, where nicotine was dosed by continuous smoking of cigarettes using a smoking machine.…”