Researchers from the Lawrence Berkeley National Laboratory have recently conducted a study, which claims that thirdhand smoke may cause a noticeable damage in human genes.
Thirdhand smoke, which is basically residue which clings to surfaces after the secondhand smoke emitted from a cigarette has cleared out, may cause a permanent damage in human gene cells, according to the study.
The study further explained that chronic exposure to thirdhand smoke may be much worse than acute exposure, suggesting that the residue may turn harmful as time passes.
"This is the very first study to find that thirdhand smoke is mutagenic," Berkeley lab scientist and co-author of the study, Lara Gundel, explained. "Tobacco-specific nitrosamines, some of the chemical compounds in thirdhand smoke, are among the most potent carcinogens there are. They stay on surfaces, and when those surfaces are clothing or carpets, the danger to children is especially serious."
To test the genotoxicity of the thirdhand smoke, the researchers used two invitro assays-the Comet assay and the long amplicon-qPCR assay. Their analysis revealed that the thirdhand smoke caused the DNA strands to break, and also led to oxidative DNA damage, which further led to gene mutation.
Genotoxicity is normally associated with many diseases, including life-threatening ones like cancer.
"Until this study, the toxicity of thirdhand smoke has not been well understood," lead investigator and biochemist in Life Science Division of Berkeley Lab, Bo Hang explained. "Thirdhand smoke has a smaller quantity of chemicals than secondhand smoke, so it's good to have experimental evidence to confirm its genotoxicity."
Thirdhand smoke is known to be quite persistent and difficult to eradicate. Many studies have also revealed that thirdhand smoke is found on the surfaces of apartments even above 2 months after the smokers have moved out.
Commonly used cleaning methods, including vacuuming, wiping, ventilation, etc have also proved to be ineffective in completely removing traces of the nicotine. "You can do some things to reduce the odors, but it's very difficult to really clean it completely. The best solution is to substitute materials, such as change the carpet, repaint," Hugo Destaillats, a scientist from the University of Texas, who was involved in the study, said.
"Ultimately, knowledge of the mechanisms by which thirdhand smoke exposure increases the chance of disease development in exposed individuals should lead to new strategies for prevention," the researchers concluded in their paper, published in the journal, Mutagenesis.
