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Assessing population health from exposure to tobacco-specific carcinogens in Belgium using an innovative wastewater-based epidemiology approach

Periodic Reporting for period 1 - APOLLO (Assessing population health from exposure to tobacco-specific carcinogens in Belgium using an innovative wastewater-based epidemiology approach)

Reporting period: 2017-04-01 to 2019-03-31

Tobacco use is the major cause of many chronic diseases, especially cancer. National questionnaire surveys are currently the main source of population tobacco smoking for characterising public health. But, it has clear limitations as it depends on true self-reported data. An additional approach allowing more objective assessment is essential to address this important societal issue. The overall objective of the APOLLO project (MSC IF Project no.: 749845) was to develop an innovative approach, wastewater-based epidemiology (WBE), for assessing community exposure to tobacco and related carcinogens. This involved wastewater analysis from several European communities for tobacco-specific chemicals of usage (tobacco alkaloids) and cancer risk (tobacco-specific nitrosamines (TSNAs)). Three key aims were achieved: (1) establishment of WBE methodology for tobacco-specific chemicals; (2) evaluation of tobacco alkaloid and TSNA levels in wastewater from different European communities; (3) assessment of population health from use of and exposure to tobacco-specific chemicals in the populations. The completion of the project resulted in advanced knowledge. A novel analytical procedure that allows the simultaneous measurement of various tobacco-related toxic and carcinogenic compounds in wastewater was developed. The methodology was successfully applied to wastewater from the communities in Belgium, Greece and Switzerland, where policies of tobacco control are different. This exploratory study assessed for the first time the occurrence and relationship between tobacco-related toxicants and carcinogens over four European cities. Geographic patterns of tobacco markers suggested higher levels of tobacco use in Geneva and Athens than Geraardsbergen and Ninove over the studied period. Relationships between the levels of tobacco markers and nicotine biomarkers reflected substantial use of non-tobacco nicotine items besides tobacco products. The detection of carcinogens was linked to environmental third-hand smoke, with elevated levels noticed in Athens where indoor smoking is not strictly prohibited, and therefore widespread of third-hand smoke. Our novel outcome highlights the future need of intervention strategies in reducing exposure to third-hand smoke in the population. WBE is a useful tool to assess population-wide tobacco use and examine exposure to tobacco carcinogens associated with third-hand smoke at the population level. Given that third-hand smoke is an emerging dimension of concern, this study based on WBE provides a new perspective that evaluates the extent of this problem and also an additional knowledge on a newly recognised threat to human and population health.
Three aims were fully completed in a year. The study focused on (bio)markers (parents and metabolites) used in clinical studies as urinary analysis of smokers to assess tobacco use and the associated health outcomes, essentially cancer. Thus, the key group of target chemicals in this study consists of tobacco-specific nitrosamines (TSNAs), tobacco alkaloids, and their metabolites. Eleven compounds were selected, including TSNAs: N-nitrosoanabasine (NAB), N-nitrosoanatabine (NAT), N-nitrosonornicotine (NNN), 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the specific metabolites of NNK (4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), NNAL-N-β-glucuronide, and NNAL-O-β-glucuronide) and alkaloid toxicants: anabasine (ANABA), anatabine (ANATA), and nicotine metabolites (cotinine (COT), trans-3′-hydroxycotinine (COT-OH)).

To reach the first aim, an analytical procedure including sample preparation and instrumental analysis was optimised and developed for the measurement of the target (bio)markers in raw wastewater. The robustness of the methodology was validated with official guidelines. The analytical sensitivity of the target chemicals was estimated for the first time in raw wastewater. The analytical method was published in Analytical Chemical 2017, 89(17), pp. 9268-9278, a high ranking peer-review journal in analytical chemistry. Green open access is provided via the UA’s library.

Moving to the second aim, the validated analytical procedure was applied to measure concentrations of the target (bio)markers in wastewater samples collected from communities in three European countries where have different tobacco control policies. This collaborative work with other European countries was based on the research network of the Sewage Analysis Core Group Europe. Measured concentrations of the target (bio)markers were computed to population-normalised mass loads as the resulting dataset for comparison across communities.

With the obtained dataset, the final aim was achieved through the assessment of population health from tobacco use and exposure to tobacco-specific chemicals in the studied communities. Briefly, among the target (bio)markers, COT-OH, COT, ANATA, ANABA and NNK were ubiquitous in wastewater from the studied populations. NNN and NAT were also detected in some of the samples. Geographic profiles of ANABA and ANATA reflected higher levels of tobacco use in Geneva (Switzerland) and Athens (Greece) compared to Geraardsbergen and Ninove (Belgium) over the monitoring period. Besides tobacco products, population-wide consumption and exposure to non-tobacco nicotine items (e.g. electronic cigarettes) resulted in the presence of COT and COT-OH in wastewater. Furthermore, the NNK detection in the wastewater samples appeared associated with the environmental third-hand smoke, highlighting potential health risks to the populations. Particularly, Athens, where indoor smoking is not strictly executed and therefore widespread, showed the highest levels of NNK. This was in line with its presence in high amounts measured in third-hand smoke, as reported in previous studies via indoor air and surface wiping analyses. The finding remarks the future exploitation for intervention policies in reducing population-wide exposure to third-hand smoke in Greece. This work has been recently submitted to Scientific Report, an open access and high ranking peer-review journal in multidisciplinary science. This project has been also disseminated via an oral presentation in the 3rd International conference on “Wastewater-Based Drug Epidemiology” (26-27 October 2017 Portugal).
The project outcomes are highly relevant to Europe and worldwide. The first impact is about the developed analytical method, which is essential for one to measure the most common toxicants and carcinogens due to tobacco use in water matrices. The finding of these chemicals in raw wastewater also reminds the importance of treatment techniques in the removal efficiency for these compounds to maintain higher water quality, which is one of the front line European priorities. Another impact is directed to the novel finding about the detection of carcinogens in wastewater attributed to environmental third-hand smoke. This is of high societal relevant, particularly in Athens. Communications with the health department in Greece about the finding are planned, aiming to reinforce prohibition of indoor smoking. This project shows an unique example for places where indoor smoking is not strictly enforced to examine exposure to tobacco carcinogens associated with third-hand smoke at the population level. This also impacts on prioritising further intervention resources against population tobacco use and exposure to its carcinogens.
Presentations to undergraduate students
Presentations at conferences