Metal Concentrations in e-Cigarette Liquid and Aerosol Samples: The Contribution of Metallic Coils

Pablo Olmedo, Walter Goessler, Stefan Tanda, Maria Grau-Perez, Stephanie Jarmul, Angela Aherrera, Rui Chen, Markus Hilpert, Joanna E Cohen, Ana Navas Acien, Ana M Rule

Research output: Contribution to journalArticle

Abstract

BACKGROUND: Electronic cigarettes (e-cigarettes) generate an aerosol by heating a solution (e-liquid) with a metallic coil. Whether metals are transferred from the coil to the aerosol is unknown.

OBJECTIVE: Our goal was to investigate the transfer of metals from the heating coil to the e-liquid in the e-cigarette tank and the generated aerosol.

METHODS: We sampled 56 e-cigarette devices from daily e-cigarette users and obtained samples from the refilling dispenser, aerosol, and remaining e-liquid in the tank. Aerosol liquid was collected via deposition of aerosol droplets in a series of conical pipette tips. Metals were reported as mass fractions (μg/kg) in liquids and converted to mass concentrations (mg/m3) for aerosols.

RESULTS: Median metal concentrations (μg/kg) were higher in samples from the aerosol and tank vs. the dispenser (all p<0.001): 16.3 and 31.2 vs. 10.9 for Al; 8.38 and 55.4 vs. <0.5 for Cr; 68.4 and 233 vs. 2.03 for Ni; 14.8 and 40.2 vs. 0.476 for Pb; and 515 and 426 vs. 13.1 for Zn. Mn, Fe, Cu, Sb, and Sn were detectable in most samples. Cd was detected in 0.0, 30.4, and 55.1% of the dispenser, aerosol, and tank samples respectively. Arsenic was detected in 10.7% of dispenser samples (median 26.7μg/kg) and these concentrations were similar in aerosol and tank samples. Aerosol mass concentrations (mg/m3) for the detected metals spanned several orders of magnitude and exceeded current health-based limits in close to 50% or more of the samples for Cr, Mn, Ni, and Pb.

CONCLUSIONS: Our findings indicate that e-cigarettes are a potential source of exposure to toxic metals (Cr, Ni, and Pb), and to metals that are toxic when inhaled (Mn and Zn). Markedly higher concentrations in the aerosol and tank samples versus the dispenser demonstrate that coil contact induced e-liquid contamination. https://doi.org/10.1289/EHP2175.

Original languageEnglish (US)
Number of pages1
JournalEnvironmental Health Perspectives
Volume126
Issue number2
DOIs
StatePublished - Feb 21 2018

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Aerosols
Tobacco Products
Metals
Poisons
Heating
Arsenic
Electronic Cigarettes
Equipment and Supplies

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

Cite this

Metal Concentrations in e-Cigarette Liquid and Aerosol Samples : The Contribution of Metallic Coils. / Olmedo, Pablo; Goessler, Walter; Tanda, Stefan; Grau-Perez, Maria; Jarmul, Stephanie; Aherrera, Angela; Chen, Rui; Hilpert, Markus; Cohen, Joanna E; Navas Acien, Ana; Rule, Ana M.

In: Environmental Health Perspectives, Vol. 126, No. 2, 21.02.2018.

Research output: Contribution to journalArticle

Olmedo, P, Goessler, W, Tanda, S, Grau-Perez, M, Jarmul, S, Aherrera, A, Chen, R, Hilpert, M, Cohen, JE, Navas Acien, A & Rule, AM 2018, 'Metal Concentrations in e-Cigarette Liquid and Aerosol Samples: The Contribution of Metallic Coils', Environmental Health Perspectives, vol. 126, no. 2. https://doi.org/10.1289/EHP2175
Olmedo, Pablo ; Goessler, Walter ; Tanda, Stefan ; Grau-Perez, Maria ; Jarmul, Stephanie ; Aherrera, Angela ; Chen, Rui ; Hilpert, Markus ; Cohen, Joanna E ; Navas Acien, Ana ; Rule, Ana M. / Metal Concentrations in e-Cigarette Liquid and Aerosol Samples : The Contribution of Metallic Coils. In: Environmental Health Perspectives. 2018 ; Vol. 126, No. 2.
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abstract = "BACKGROUND: Electronic cigarettes (e-cigarettes) generate an aerosol by heating a solution (e-liquid) with a metallic coil. Whether metals are transferred from the coil to the aerosol is unknown.OBJECTIVE: Our goal was to investigate the transfer of metals from the heating coil to the e-liquid in the e-cigarette tank and the generated aerosol.METHODS: We sampled 56 e-cigarette devices from daily e-cigarette users and obtained samples from the refilling dispenser, aerosol, and remaining e-liquid in the tank. Aerosol liquid was collected via deposition of aerosol droplets in a series of conical pipette tips. Metals were reported as mass fractions (μg/kg) in liquids and converted to mass concentrations (mg/m3) for aerosols.RESULTS: Median metal concentrations (μg/kg) were higher in samples from the aerosol and tank vs. the dispenser (all p<0.001): 16.3 and 31.2 vs. 10.9 for Al; 8.38 and 55.4 vs. <0.5 for Cr; 68.4 and 233 vs. 2.03 for Ni; 14.8 and 40.2 vs. 0.476 for Pb; and 515 and 426 vs. 13.1 for Zn. Mn, Fe, Cu, Sb, and Sn were detectable in most samples. Cd was detected in 0.0, 30.4, and 55.1{\%} of the dispenser, aerosol, and tank samples respectively. Arsenic was detected in 10.7{\%} of dispenser samples (median 26.7μg/kg) and these concentrations were similar in aerosol and tank samples. Aerosol mass concentrations (mg/m3) for the detected metals spanned several orders of magnitude and exceeded current health-based limits in close to 50{\%} or more of the samples for Cr, Mn, Ni, and Pb.CONCLUSIONS: Our findings indicate that e-cigarettes are a potential source of exposure to toxic metals (Cr, Ni, and Pb), and to metals that are toxic when inhaled (Mn and Zn). Markedly higher concentrations in the aerosol and tank samples versus the dispenser demonstrate that coil contact induced e-liquid contamination. https://doi.org/10.1289/EHP2175.",
author = "Pablo Olmedo and Walter Goessler and Stefan Tanda and Maria Grau-Perez and Stephanie Jarmul and Angela Aherrera and Rui Chen and Markus Hilpert and Cohen, {Joanna E} and {Navas Acien}, Ana and Rule, {Ana M}",
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T1 - Metal Concentrations in e-Cigarette Liquid and Aerosol Samples

T2 - The Contribution of Metallic Coils

AU - Olmedo, Pablo

AU - Goessler, Walter

AU - Tanda, Stefan

AU - Grau-Perez, Maria

AU - Jarmul, Stephanie

AU - Aherrera, Angela

AU - Chen, Rui

AU - Hilpert, Markus

AU - Cohen, Joanna E

AU - Navas Acien, Ana

AU - Rule, Ana M

PY - 2018/2/21

Y1 - 2018/2/21

N2 - BACKGROUND: Electronic cigarettes (e-cigarettes) generate an aerosol by heating a solution (e-liquid) with a metallic coil. Whether metals are transferred from the coil to the aerosol is unknown.OBJECTIVE: Our goal was to investigate the transfer of metals from the heating coil to the e-liquid in the e-cigarette tank and the generated aerosol.METHODS: We sampled 56 e-cigarette devices from daily e-cigarette users and obtained samples from the refilling dispenser, aerosol, and remaining e-liquid in the tank. Aerosol liquid was collected via deposition of aerosol droplets in a series of conical pipette tips. Metals were reported as mass fractions (μg/kg) in liquids and converted to mass concentrations (mg/m3) for aerosols.RESULTS: Median metal concentrations (μg/kg) were higher in samples from the aerosol and tank vs. the dispenser (all p<0.001): 16.3 and 31.2 vs. 10.9 for Al; 8.38 and 55.4 vs. <0.5 for Cr; 68.4 and 233 vs. 2.03 for Ni; 14.8 and 40.2 vs. 0.476 for Pb; and 515 and 426 vs. 13.1 for Zn. Mn, Fe, Cu, Sb, and Sn were detectable in most samples. Cd was detected in 0.0, 30.4, and 55.1% of the dispenser, aerosol, and tank samples respectively. Arsenic was detected in 10.7% of dispenser samples (median 26.7μg/kg) and these concentrations were similar in aerosol and tank samples. Aerosol mass concentrations (mg/m3) for the detected metals spanned several orders of magnitude and exceeded current health-based limits in close to 50% or more of the samples for Cr, Mn, Ni, and Pb.CONCLUSIONS: Our findings indicate that e-cigarettes are a potential source of exposure to toxic metals (Cr, Ni, and Pb), and to metals that are toxic when inhaled (Mn and Zn). Markedly higher concentrations in the aerosol and tank samples versus the dispenser demonstrate that coil contact induced e-liquid contamination. https://doi.org/10.1289/EHP2175.

AB - BACKGROUND: Electronic cigarettes (e-cigarettes) generate an aerosol by heating a solution (e-liquid) with a metallic coil. Whether metals are transferred from the coil to the aerosol is unknown.OBJECTIVE: Our goal was to investigate the transfer of metals from the heating coil to the e-liquid in the e-cigarette tank and the generated aerosol.METHODS: We sampled 56 e-cigarette devices from daily e-cigarette users and obtained samples from the refilling dispenser, aerosol, and remaining e-liquid in the tank. Aerosol liquid was collected via deposition of aerosol droplets in a series of conical pipette tips. Metals were reported as mass fractions (μg/kg) in liquids and converted to mass concentrations (mg/m3) for aerosols.RESULTS: Median metal concentrations (μg/kg) were higher in samples from the aerosol and tank vs. the dispenser (all p<0.001): 16.3 and 31.2 vs. 10.9 for Al; 8.38 and 55.4 vs. <0.5 for Cr; 68.4 and 233 vs. 2.03 for Ni; 14.8 and 40.2 vs. 0.476 for Pb; and 515 and 426 vs. 13.1 for Zn. Mn, Fe, Cu, Sb, and Sn were detectable in most samples. Cd was detected in 0.0, 30.4, and 55.1% of the dispenser, aerosol, and tank samples respectively. Arsenic was detected in 10.7% of dispenser samples (median 26.7μg/kg) and these concentrations were similar in aerosol and tank samples. Aerosol mass concentrations (mg/m3) for the detected metals spanned several orders of magnitude and exceeded current health-based limits in close to 50% or more of the samples for Cr, Mn, Ni, and Pb.CONCLUSIONS: Our findings indicate that e-cigarettes are a potential source of exposure to toxic metals (Cr, Ni, and Pb), and to metals that are toxic when inhaled (Mn and Zn). Markedly higher concentrations in the aerosol and tank samples versus the dispenser demonstrate that coil contact induced e-liquid contamination. https://doi.org/10.1289/EHP2175.

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