@article{35427,
  keywords = {Nicotine, HONO, Skin liquids, Cancer risk, C57BL/6 mice, Thirdhand},
  author = {Xiaochen Tang and Neal L Benowitz and Lara A Gundel and Bo Hang and Christopher Havel and Eunha Hoh and Peyton Jacob III and Jian-Hua Mao and Manuela Martins-Green and Georg E Matt and Penelope J. E Quintana and Marion L Russell and Altaf H Sarker and Suzaynn F Schick and Antoine M Snijders and Hugo Destaillats},
  title = {Thirdhand Exposures to Tobacco-Specific Nitrosamines through Inhalation, Dust Ingestion, Dermal Uptake, and Epidermal Chemistry},
  abstract = {<p>Tobacco-specific nitrosamines (TSNAs) are emitted during smoking and form indoors by nitrosation of nicotine. Two of them, <em>N</em>′-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are human carcinogens with No Significant Risk Levels (NSRLs) of 500 and 14 ng day<sup>–1</sup>, respectively. Another TSNA, 4-(methylnitrosamino)-4-(3-pyridyl) butanal (NNA), shows genotoxic and mutagenic activity <em>in vitro</em>. Here, we present additional evidence of genotoxicity of NNA, an assessment of TSNA dermal uptake, and predicted exposure risks through different pathways. Dermal uptake was investigated by evaluating the penetration of NNK and nicotine through mice skin. Comparable mouse urine metabolite profiles suggested that both compounds were absorbed and metabolized <em>via</em> similar mechanisms. We then investigated the effects of skin constituents on the reaction of adsorbed nicotine with nitrous acid (<em>epidermal chemistry</em>). Higher TSNA concentrations were formed on cellulose and cotton substrates that were precoated with human skin oils and sweat compared to clean substrates. These results were combined with reported air, dust, and surface concentrations to assess NNK intake. Five different exposure pathways exceeded the NSRL under realistic scenarios, including inhalation, dust ingestion, direct dermal contact, gas-to-skin deposition, and epidermal nitrosation of nicotine. These results illustrate potential long-term health risks for nonsmokers in homes contaminated with thirdhand tobacco smoke.</p>},
  year = {2022},
  journal = {Environmental Science & Technology},
  volume = {56},
  number = {17},
  month = {09/2022},
  url = {https://pubs.acs.org/doi/10.1021/acs.est.2c02559},
  doi = {https://doi.org/10.1021/acs.est.2c02559},
  language = {eng},
}