Electronic Cigarettes Are a Source of Thirdhand Exposure to Nicotine

Maciej L. Goniewicz and Lily Lee have published a paper, "Electronic Cigarettes Are a Source of Thirdhand Exposure to Nicotine" in Nicotine and Tobacco Research.  The title says it all, but here is the abstract:
 

Introduction: Substances remaining on the surfaces in areas where people have smoked contribute to thirdhand exposure. Nicotine from tobacco smoke has been shown to react with oxidizing chemicals in the air to form secondary pollutants, such as carcinogenic nitrosamines. While previous studies have demonstrated thirdhand exposure to nicotine from tobacco smoke, none has investigated whether nicotine from electronic cigarettes (e-cigarettes) can also be deposited on various surfaces.
 

Methods: Three brands of e-cigarettes were refilled with varying nicotine concentrations. We released 100 puffs from each product directly into an exposure chamber. Surface wipe samples were taken from five indoor 100cm2 surfaces (window, walls, floor, wood, and metal) pre and post release of vapors. Nicotine was extracted from the wipes and analyzed using gas chromatography.

 
Results: Three of four experiments showed significant increases in the amount of nicotine on all five surfaces. The floor and glass windows had the greatest increases in nicotine, on average by a factor of 47 and 6, respectively (p < .05). The average amount of nicotine deposited on a floor during each experiment was 205 μg/m2, and varied from limit of quantitation to 550 μg/m2.

 
Conclusions: This study indicates that there is a risk of thirdhand exposure to nicotine from e-cigarettes. Thirdhand exposure levels differ depending on the surface and e-cigarette brand. Future research should explore the potential risks of thirdhand exposure to carcinogens formed from nicotine released from e-cigarettes.

 
The paper is available here.

Comments

Thirdhand e-cig nicotine = continuous exposure to carcinogens

I was at the American Nonsmokers Rights Foundation Fallen Leaf Lake "Clearing the Air Retreat" earlier this week where I attended two excellent lectures on the science of thirdhand smoke by Georg Matt from California State University San Diego, where he explained the chemistry and physics of thirdhand smoke.   As Goniewicz and Lee note, the nicotine in the smoke continues to react with chemicals in the air to create tobacco specific nitrosamines (strong carcinogens) for a long time.  Matt made the point that thirdhand smoke leads to long-term continuous low levels of these carcinogens.  The same is true for thirdhand e-cigarette vapor.

Exposure mechanism?

It is unlikley that significant exposure could occur unless a plausible exposure mechanism is identified, from the levels indicated people would have to lick many m2 of floor and wall surface to expose thmselves to a measurable quantity of nicotine.
Surley the title of this study should be "risk from 3rd hand exposure to e-cig vapour negligible"?
 
 

Infants and small children

.. crawl on the floor and touch other surfaces then put their hands in their mouth.

Pointless research with a misleading title

Actually the title does not say it all' - it actually says nothing useful at all, and is misleading and irrelevant. 
This experiemnt did not measure 'exposure' but 'deposition' on surfaces in a chamber. For there to be 'exposure', a pathway between the inanimate surace and the blood or brain needs to be identified.  The main risk appears to be to people who lick windows - or 'window-lickers' as they are known on the Internet.  However, even these people, who have other problems and priorities, would have to lick the deposition from 38 square meters of glass in this chamber to be exposed to 1mg of nicotine (47/6*1000/205). Obviously, in a full sized room, where the deposition density might be expected to be lower than in a chamber, the area required for window licking would be greater.  
What is the point of publicising and spinning this sort of ressearch as if it somehow helps to articulate a meaningful risk? If it tells us anything at all, it is that this is irrelevant. 
Clive Bates

Infants and small children are most at risk

They crawl around on the floor and put their hands in their mouth.

Moreover:

Moreover:
 


  • Goniewicz and Lee state in the Abstract: “Nicotine from tobacco smoke has been shown to react with oxidizing chemicals in the air to form secondary pollutants, such as carcinogenic nitrosamines.” And then:

 

  • “Future research should explore the potential risks of thirdhand exposure to carcinogens formed from nicotine released from e-cigarettes.” And then:

 

  • Perhaps the key Key Paper for their study is: “Formation of carcinogens indoors by surface-mediated reactions of nicotine with nitrous acid, leading to potential thirdhand smoke hazards” Mohamad Sleiman et al

 
“This study shows that residual nicotine from tobacco smoke sorbed to indoor surfaces reacts with ambient nitrous acid (HONO) to form carcinogenic tobacco-specific nitrosamines (TSNAs). Substantial levels of TSNAs were measured on surfaces inside a smoker’s vehicle. Laboratory experiments using cellulose as a model indoor material yielded a >10-fold increase of surface-bound TSNAs when sorbed secondhand smoke was exposed to 60 ppbv HONO for 3 hours. In both cases we identified 1-(N-methyl-N-nitrosamino)- 1-(3-pyridinyl)-4-butanal, a TSNA absent in freshly emitted tobacco smoke, as the major product. The potent carcinogens 4-(methylnitrosamino)- 1-(3-pyridinyl)-1-butanone and N-nitroso nornicotine were also detected. Time-course measurements revealed fast TSNA formation, with up to 0.4% conversion of nicotine. Given the rapid sorption and persistence of high levels of nicotine on indoor surfaces— including clothing and human skin—this recently identified process represents an unappreciated health hazard through dermal exposure, dust inhalation, and ingestion. These findings raise concerns about exposures to the tobacco smoke residue that has been recently dubbed “thirdhand smoke.” Our work highlights the importance of reactions at indoor interfaces, particularly those involving amines and NOx/HONO cycling, with potential health impacts.” (my emphasis)
 Therefore:
 

  1. There are many “surfaces” to be considered here, not just floors, windows etc but vehicles, chairs, beds, clothing, skin . . . . . and

  2. The authors more probaly more concerned about exposure to “potent carcinogens”/TSNAs, produced by interactions between nicotine and nitrous acid, rather than nicotine per se, but still concerned about nicotine . . .

  3. And if so, what levels of exposures here, to TSNAs, are agreed to be potentially harmful?

  4. Some state that there are NO safe levels of exposure to carcinogens, therefore

  5. The Authors work is far from irrelevant, but in fact a piece of progressive science, building positively on previous work and proposing further development of work in this area, and therefore needs to be applauded, rather than ridiculed.

 
 David W Bareham BSc Hons (Physiotherapy) MSc (Pain Management).
Specialist Respiratory Physiotherapist

Moreover . . .

This is now "out there", posted on The Counterfactual website:
 
Dear Clive
May I respectfully, but strongly suggest, that you have misinterpreted the purpose, results and direction of the very recent Goniewicz and Lee paper here: http://ntr.oxfordjournals.org/content/early/2014/08/28/ntr.ntu152.abstract.html. My reasoning is thus:


  • Goniewicz and Lee initially state clearly in their Abstract: “Nicotine from tobacco smoke has been shown to react with oxidizing chemicals in the air to form secondary pollutants, such as carcinogenic nitrosamines.” And then, in conclusion, state:

  • “Future research should explore the potential risks of thirdhand exposure to carcinogens formed from nicotine released from e-cigarettes.” And then, if you correctly appraise  the research:

  • Perhaps the “Key Paper” for their study is: “Formation of carcinogens indoors by surface-mediated reactions of nicotine with nitrous acid, leading to potential thirdhand smoke hazards” Mohamad Sleiman et al, and they state that:

 “This study shows that residual nicotine from tobacco smoke sorbed to indoor surfaces reacts with ambient nitrous acid (HONO) to form carcinogenic tobacco-specific nitrosamines (TSNAs). Substantial levels of TSNAs were measured on surfaces inside a smoker’s vehicle. Laboratory experiments using cellulose as a model indoor material yielded a >10-fold increase of surface-bound TSNAs when sorbed secondhand smoke was exposed to 60 ppbv HONO for 3 hours. In both cases we identified 1-(N-methyl-N-nitrosamino)- 1-(3-pyridinyl)-4-butanal, a TSNA absent in freshly emitted tobacco smoke, as the major product. The potent carcinogens 4-(methylnitrosamino)- 1-(3-pyridinyl)-1-butanone and N-nitroso nornicotine were also detected. Time-course measurements revealed fast TSNA formation, with up to 0.4% conversion of nicotine. Given the rapid sorption and persistence of high levels of nicotine on indoor surfaces— including clothing and human skin—this recently identified process represents an unappreciated health hazard through dermal exposure, dust inhalation, and ingestion. These findings raise concerns about exposures to the tobacco smoke residue that has been recently dubbed “thirdhand smoke.” Our work highlights the importance of reactions at indoor interfaces, particularly those involving amines and NOx/HONO cycling, with potential health impacts.” (my emphasis) Therefore:

  1. There are many “surfaces” to be considered here, not just floors, windows etc but vehicles, chairs, beds, clothing, skin . . . . . and

  2. The authors are probably more concerned about exposure to “potent carcinogens”/TSNAs, produced by interactions between nicotine and sources of nitrous acid, rather than nicotine per se, but still concerned about nicotine . . . and

  3. Therefore, what levels of exposures here, to TSNAs, are agreed to be potentially harmful? This is something that you fail to even mention in your “critique”, subsequent to your focus on nicotine.

  4. Some state that there are NO safe levels of exposure to carcinogens, and therefore

  5. The Authors work is far from irrelevant, but in fact a piece of progressive science, building positively on previous work and proposing further development of work in this “unappreciated” area: and therefore needs to be applauded, rather than ridiculed.

  6. I believe that Goniewicz, judging from previous work that you note, wants e-cigarettes “to work”, but, as he is a conscientious scientist, he will not let his schema over-ride the necessity to explore all possible causes of harm to all populations.

 
Moreover, please can you explain these following significant incongruities?
 

  1. At this year’s Global Forum on Nicotine Conference, Riccardo Polosa here http://www.youtube.com/watch?v=CdB-HffpuwM   states in slides that nicotine is “a neurostimulant (NOT a poison)” – his emphasis. However, at the same Conference, here http://www.youtube.com/watch?v=oYnyHDG_vq8 Maciej Goniewicz clearly states in slides that nicotine IS a poison. There is clearly a significant difference of opinion here, which needs an explanation. Moreover, if there really is such a difference of opinion about such a central issue, then the only logical and ethical approach to issues surrounding nicotine is: a precautionary one.  

  2. Riccardo Polosa states clearly in the above link that he believes that Propylene Glycol (PG) utilised in electronic cigarettes is “Safe”. However, Dr Farsalinos states here http://www.ecigarette-research.com/web/index.php/research/2014/182-lung-detox   http://www.ecigarette-research.com/web/index.php/research/2014/182-lung-detox    that:

“It is true, and I have mentioned it repeatedly, that a GRAS substance for ingestion does not necessarily mean that it is safe for inhalation. However, it neither means that it is not safe.”
There is this data http://www.ncbi.nlm.nih.gov/pubmed/11555686 furthermore which is cited in the recent AHA Statement on electronic cigarettes as you know, but possibly more importantly I believe, Dr Farsalinos has stated to me in email:
 
“to tell you the truth i am more worried about the formation of formaldehyde from thermal decomposition of PG rather than PG itself.”
 
As these two gentlemen both published together a key paper on a safety evaluation of the chemical composition of electronic cigarettes here http://taw.sagepub.com/content/5/2/67.short, should there not be agreement between them on this key issue?
 

  1. Furthermore, here http://www.bbc.co.uk/news/health-27161965 and here https://www.youtube.com/watch?v=gm90YJRQcRk Peter Hajek and John Britton respectively both state that the effects of nicotine are akin to caffeine. Here http://www.youtube.com/watch?v=oYnyHDG_vq8 Maciej Goniewicz states that nicotine alone “is generally accepted as a tumor promoter” and that “it’s metabolites can promote tumor growth”. This opinion is supported here:    http://www.carcinogenesis.com/article.asp?issn=1477-3163;year=2013;volume=12;issue=1;spage=1;epage=1;aulast=Warren where the authors state that: “Nicotine and its metabolites can promote tumor growth through increased proliferation, angiogenesis, migration, invasion, epithelial to mesenchymal transition, and stimulation of autocrine loops associated with tumor growth. Furthermore, nicotine can decrease the biologic effectiveness of conventional cancer treatments such as chemotherapy and radiotherapy.” Does caffeine, therefore, if Peter and John are correct, also cause these significantly negative effects?

  2. This study by David Nutt et al http://www.karger.com/Article/Pdf/360220, which is also cited by Riccardo Polosa in the GNF link above, was formalised in July 2013 and published in April 2014. This means that it could not consider the data from the Kosmider et al and Hutzler et al data that we have previously discussed. Should therefore the “weighting” for ENDS be adjusted to account for this recognition for increased potential harm? Please note here http://www.ecigarette-research.com/web/index.php/research/2014/181-who-resp    that Dr Farsalinos, regarding the Kosmider et al paper, states that: “the levels of carbonyls emitted from e-cigarettes can (under certain conditions) be similar to or higher than smoking”.

  3. I note here http://www.bibra-information.co.uk/e-cigarettes/ from this link http://www.fridays-group.com/2014/07/e-cigarette-risks-grossly-exaggerated-safer-than-washing-up-claim-experts/  that independent services are available for electronic cigarette companies to have their products tested for safety/toxicology. Moreover, I note here http://www.bibra-information.co.uk/portfolio/provision-hazard-risk-assessments-hundreds-flavourings-electronic-cigarettes/ that bibra state that:

 
“The toxicological acceptability of such substances has historically been assessed for food and cosmetics applications, and their safety for use in electronic cigarettes (as inhaled flavourings) now needs to be substantiated.”
 
It is heartening to see ECITA, therefore, finally testing “hundreds” of flavourings, but ironically, the links are found through the link above: the one claiming that electronic cigarette use is safer than washing up. Would you agree that such current claims about the safety profile of electronic cigarettes are, therefore, both presumptuous and premature? As this http://ntr.oxfordjournals.org/content/early/2014/09/22/ntr.ntu197.abstract very recent review states: “Since new potentially harmful substances may be produced during heating process, analyses of aerosol are needed to correlate its composition to the chemical components of liquids.” This clearly relates to both solvents (e.g. production of carbonyl carcinogens and toxins) and flavourings, as well, possibly, as identified “contaminants” e.g. coumarin (see Hutzler et al).
 

  1. Finally, I note with interest here http://tobaccoanalysis.blogspot.co.uk/2014/09/discontinuation-of-crowdfunding.html an extraordinary and very recent statement from the ardent pro-harm reduction advocate, Professor Michael Siegel. He states that:

 
“Unfortunately, however, we discovered that there is great divisiveness within the e-cigarette community regarding the role of research—including what type of research should be done, who should do it, and who should pay for it. We welcomed feedback and suggestions about creating an optimal study design for BSCiTS, and we sought to be responsive to concerns about study methodology. However, the tone of feedback directed at our team quickly became hostile. Our integrity as researchers was questioned, and criticism quickly shifted from concerns about study methods to personal attacks.”
Would you agree that such apparent divisiveness from some segments, at least, of the e-cigarette industry about the role of research and the integrity of researchers, is incongruous with the scientific method and with public health?
Yours sincerely
David Bareham 
 
 
 
David W Bareham BSc Hons (Physiotherapy) MSc (Pain Management).
Specialist Respiratory Physiotherapist
Lincolnshire Community Health Services NHS Trust
Locality Office
Louth County Hospital
Louth
LN11 0EU

Response to Clive's Response.

Clive's Response:  


  • Sorry I don’t have time to leave a lengthy reply.

0. The paper is focussed on “3rd hand nicotine exposure” – see its title. The exposure to environmental carcinogens from this source would be very low indeed and the pathways highly unlikely to lead to any material risk. I don’t have it here, but I don’t think they measured carcinogens – if they had, it would be a useful discussion. There are several other flaws in this work. As I said in the actual post on this, let them form a hypothesis, give their reason why they think it is plausible, and then devise tests to falsify it. This they have not done.
1. Nicotine is a poison at high doses, not at low doses.
2. PG has ‘generally recognised as safe’ status, including for inhalation. Thermal breakdown products are an issue – but only become significant when the product is used in extreme circumstances, running very hot or dry. Polosa and Farsalinos statements are not inconsistent.
3. The comparison with caffeine used by these experts is to give a scale of risk that makes sense to ordinary people, not to say that the risks are identical. They do this to stop the negative harmful effects of public health representatives overstating risks – implicitly or explicitly – and therefore frightening people back into using cigarettes or not switching You may be doing this yourself. ‘Tumour promoter’ is widely misused or misunderstood and the evidence for it is highly speculative – based on very high doses administered in mice study.
4. The Kosminder study produced higher level of some toxicants only when the devices were run under unrealistic conditions. It would not change the estimate in the Nutt et al MCDA. The fact that they attributed any risk at all to these products was to anticipate unknowns, because there is nothing at present that suggests any material risk.
5. ECITA’s claim relates to the safety profile of nicotine liquids at retail concentrations for accidental exposure – their analysis makes that clear, and their conclusion is that it as hazardous as washing up liquid. I see no flaws in their reasoning. I support some testing and regulation to get a better insights into flavours – but the greatest danger is that excessive regulatory reaction to minute risks will compromise the appeal of e-cigarettes to smokers and we end up with more smoking. So when you raise these issues, do please keep in your mind that your extreme risk aversion on behalf of others, may be putting people at far greater risk than those you are keen (or their behalf) for them to avoid.
6. The disagreement over the proposed crowd sourced research was over: whether it would yield useful results; whether RCTs are the right way to understand this phenomenon; whether it was a realistic ask for crowd-funding; what opportunity costs it would create. Dispute is at the heart of the scientific process. If you want to look at junk science and improper scientific discourse, I would suggest starting with tobacco control science and related spin.
I’m assuming you aren’t a vaper. I believe you work for the NHS. If I may give you some advice, the approach you are taking here (unquantified emphasis on very small or implausible cherry-picked risks) is a very harmful form of risk communication and the subject of most of my report on WHO. It is likely to discourage people from trying vaping as an alternative to smoking. The result will be more smoking and more death and disease.
My Response, awaiting authorisation on his website:
 
RESPONSE.
 

  1. With all due respect, Clive, I am somewhat baffled that, after you stated that you had analysed this paper in depth so recently, and have posted opinion on both yours and other’s blogs, that: you cannot remember if carcinogens were either a primary or a secondary outcome measure. The paper, of course, did not look at carcinogens, if you had read it thoroughly, and I provided the paper for you in my posting. It is a preliminary piece of work to assess for deposition of nicotine: the primary outcome measure in this stage of investigation. However, the precise reason for assessing this was to justify the need, or not, for the potential subsequent step in the correct scientific process. After detecting nicotine, they conclude and clearly state: ““Future research should explore the potential risks of thirdhand exposure to carcinogens formed from nicotine released from e-cigarettes.” This is how science should progress, one step at a time, and I would respectfully state that your suggestion of “I don’t think they measured carcinogens – if they had, it would be a useful discussion” would clearly have introduced a second “primary outcome measure”, which is not “good science”: they, or others, will look at that, next time. The paper is an example of how good science should “build on itself”, progressively (See K. Popper etc). They do give a reason why they think the hypothesis studied is plausible: I quote the key paper and they cite others (if you had read the paper and studied its reference list, you would have seen these, which is also essential critical appraisal). They tried to falsify the hypothesis this time, by testing for the deposition, or not, of nicotine.

  2. So: you agree that Polosa is incorrect, therefore. This is disappointing, I would respectfully suggest, as he had been invited to speak as an expert speaker at this Global Conference: on nicotine. Do you believe that it may call into question other statements that he makes, therefore?

  3. Please give your reference for stating “PG has ‘generally recognised as safe’ status, including for inhalation”: in an electronic cigarette. You state: “but only become significant when the product is used in extreme circumstances, running very hot or dry.” Dr Farsalinos has again pointed out to me that: “There are devices going up to 30 watts now. I consider these extreme, but a lot of people use energy levels up to 10 watts.” (my emphasis, plus also see here http://motherboard.vice.com/read/e-cigarettes-dont-look-anything-like-you-think-they-do ). Please also see Dr Farsalinos’ experiments on temperatures on You Tube, and note that Polosa, in his conclusion in the link provided, confirms that temperatures are a significant issue for concern. All potential users, all populations, should be made aware of this fact, in order that they can make an informed choice about using these devices. As stated: “Since new potentially harmful substances may be produced during heating process, analyses of aerosol are needed to correlate its composition to the chemical components of liquids.” This is why currently, at least, PG is not considered safe as utilised in an electronic cigarette: which IS THE CONTEXT we are discussing.

  4. The discussion that nicotine’s effects are akin to caffeine: I agree that the statements are made in order to encourage current smokers to consider a complete “switch”. This is admirable. However, it clearly has a flip side, as it understates the potential risks to all other potential users/populations: ex-smokers; non-smokers and youth. Youth drink coffee: therefore, listening to this, they will reasonably conclude that vaping is safe. The Times only this last weekend here http://thetim.es/1rxb5Hn stated that, at worst, children “will be driven to harmless vaping” (my emphasis). Please consider Dr Farsalinos’ words here http://www.ecigarette-research.com/web/index.php/research/2014/181-who-resp “Obviously, every non-smoker also deserves to know that the e-cigarette is not a safe new habit for everyone to adopt”. “Experts” expressing, in effect, that they consider nicotine and electronic cigarettes are as safe as caffeine, will clearly not give out this other, essential message, to protect ALL populations of potential users from potential harm. This is what The WHO is endeavoring to do, as well as to reasonably maximize any potential benefits from the devices to smokers.

  5. “The fact that they attributed any risk at all to these products was to anticipate unknowns, because there is nothing at present that suggests any material risk.” Multiple organisations disagree with you, based on the current evidence. Dr Farsalinos states that: “the electronic cigarette is not a safe new habit”, as above. Your statement appears untenable with the current evidence. You clearly understate the risks to all potential users with this statement.

  6. One of the obvious differences between electronic cigarette fluids and washing up liquid is: there are not approaching 8000 different flavours of washing up liquad (http://www.nytimes.com/2014/07/16/business/e-cigarette-makers-are-in-an-arms-race-for-exotic-vapor-flavors.html?_r=2# ). Moreover, we do not consume washing up liquid; children do not observe their parents (hopefully) consuming washing up liquid. These issues, involving any risk assessment and subsequent comparison between the two products, have to be seriously taken into account, whatever we decide about the contrasting toxicity of the fluids concerned. Moreover: you have not answered the question: do you believe that vaping is as safe as washing up, or do you believe the published manufacture’s statement to be misleading to the public? So, when you raise these issues, do please keep in your mind that your extreme understatements, on behalf of others, which I acknowledge is admirable, may be putting other people at risk: currently unknown risks. These devices are out on shelves, next to confectionary: whether placed there as a piece of “aggressive marketing”, or as a “random placement”. The later seems to me far more unlikely than the former.

  7.  “Dispute is at the heart of the scientific process.” No Clive  . . . . Siegel states: “However, the tone of feedback directed at our team quickly became hostile. Our integrity as researchers was questioned, and criticism quickly shifted from concerns about study methods to personal attacks.” This is clearly unacceptable behaviour, and one that may well do your cause dis-service. This behaviour promotes the junk science that you talk of: but you accept it as normal, and therefore in fact are advocating it. Progressive public health science cannot progress in this environment.

  8. Lastly, I am a clinician, who has already stated here http://tobacco.ucsf.edu/response-mcneill-et-al-criticism-report-we-prepared-who-and-subsequent-review-paper-circulation-ecigs how I practice:

“I am a respiratory clinician with a great interest in this issue, and I would like to point out that, from the first, I DO refer people to the their local Smoking Cessation Services for support with quitting via use of an electronic cigarette, if: they have had multiple attempts via other evidence-based methods but failed; do not wish to try anymore via those methods; and if THEY raise the topic of quitting via an electronic cigarette. I will discuss the current evidence base with them: that there is some evidence that on an individual level at least, these devices can help. I do point out that, to maximise the health benefits, that they do need to fully quit, and point out that “dual use” will reduce those potential benefits i.e. they need to “switch”. I inform them that, in my opinion, it is inconceivable that an electronic cigarette is either: more harmful, as harmful or, in fact, probably anything like as harmful, as the combustible cigarette. There is no combustion, no tar and no C02.”
You therefore pre-judge me. The approach I am advocating seeks to maximise any benefits from these devices, while also protecting all other populations from risks: unknown.
 
David Bareham