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

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

Developmental toxicity of e‐cigarette aerosols

“…As previously indicated, in addition to nicotine, ENDS usage exposes the user, including the developing conceptus, to constituents of the aerosol generated from vaporization of the base e-liquid. These include known carcinogens and toxic chemicals such as nitrosamines, formaldehyde, acetaldehyde, acrolein, propylene glycol, glycerin and the heavy metals lead, chromium, manganese and nickel (Geiss, Bianchi, Barahona, & Barrero-Moreno, 2015;Goniewicz et al, 2014;Hess, Olmedo, Navas-Acien, et al, 2017;Logue, Sleiman, Montesinos, et al, 2017;Olmedo et al, 2018;Rawlinson, Martin, Frosina, & Wright, 2017;Sleiman, Logue, Montesinos, et al, 2016;Williams, Villarreal, Bozhilov, Lin, & Talbot, 2013), all toxic when inhaled. The apparent source of many of the heavy metals is leakage from the e-cigarette heating coils into the aerosols that users inhale (Olmedo et al, 2018).…”

Peptide Bond Cleavage by Ni(II) Ions within the Nuclear Localization Signal Sequence

“…[1][2][3] Unfortunately, many objects of daily use, such as tools, coins, jewelry, or cases of mobile phones and laptops release nickel in amounts high enough to trigger a reaction of the human immune system. [3][4][5][6][7] Nickel is also abundant in the inhaled cigarette smoke (also from electronic cigarettes), [8,9] and the polluted air. [10] Inhalatory exposure to dust of poorly soluble nickel compounds is carcinogenic, elevating the risk of human lung and nasal cancers.…”

Cannabis Contaminants: Regulating Solvents, Microbes, and Metals in Legal Weed

“…Ana Rule, an assistant professor of environmental health and engineering at Johns Hopkins University, has researched metal emissions from e-cigarettes and other electronic vaporizers 31 , 32. She says she has never studied vaporizers intended specifically for use with cannabis concentrates and prefilled cartridges.…”