Background/Methods Increased use and sales of e-cigarettes raises concerns about the potential environmental impacts throughout their life-cycle. However, few available research studies focus on the environmental impacts and ecotoxicity of e-cigarettes. In this study, we short-list e-liquid chemicals from published literature that should be considered in future environmental impact and risk assessments. We used a combination of available laboratory bioassays-based data and predictive methods (eg, Structure-Activity Relationships) to characterise the hazards of the e-liquid chemicals (environmental persistence, bioaccumulation, and aquatic toxicity including hazardous concentration values (concentration affecting specific proportion of species)) for short-listing.
Results Of the 421 unique e-liquid chemicals compiled from literature, 35 are US Environmental Protection Agency’s hazardous constituents, 42 are US Food and Drug Administration’s harmful or potentially harmful constituents in tobacco products and smoke, and 20 are listed as both. Per hazard characteristics, we short-listed 81 chemicals that should be considered for future environmental impact and risk assessments, including tobacco-specific compounds (eg, nicotine, N'-nitrosonornicotine), polycyclic aromatic hydrocarbons (eg, chrysene), flavours (eg, (-)caryophyllene oxide), metals (eg, lead), phthalates (eg, di(2-ethylhexyl)phthalate) and flame retardants (eg, tris(4-methylphenyl)phosphate).
Implications Our findings documenting various hazardous chemicals in the e-liquids underscore the importance of awareness and education when handling or disposing of e-liquids/e-cigarettes and aim to inform strategies to prevent and reduce hazards from e-cigarettes. This includes any scenario where e-liquids can come into contact with people or the environment during e-liquid storage, manufacturing, use, and disposal practices. Overall, our study characterises the environmental hazards of e-liquid chemicals and provides regulators and researchers a readily available list for future ecological and health risk assessments.
- Electronic nicotine delivery devices
- Heavy Metals
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
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PDV and SAN contributed equally.
Contributors PDV: conceptualisation, methodology, investigation, software, validation, formal analysis, data curation, writing of the original draft, visualisation, project administration. PDV as the guarantor accepts full responsibility for the finished work and/or the conduct of the study, had access to the data, and controlled the decision to publish. SAN: conceptualisation, methodology, investigation, software, validation, formal analysis, data curation, writing of the review and editing, project administration. RG: conceptualisation, investigation, software, validation, formal analysis, data curation, visualisation, writing of the original draft. SMR: methodology, investigation, validation, formal analysis, data curation, writing of the original draft, visualisation. WB: software, formal analysis, investigation, writing of the review and editing. SKH: conceptualisation, investigation, software, formal analysis, writing of the original draft.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Disclaimer The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Food and Drug Administration. MultiCASE software package was made available to FDA-CTP through licensing agreement with the company (Contract number 75F40122C00072). All other software used are publicly available.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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