Analysis: Steel Heating Mechanisms of Some THC Vape Cartridges May Result in Exposure to Heavy Metals

Fife, WA: The use of certain portable THC vape cartridges may be associated with inadvertent exposure to various heavy metals, according to data published in the journal Chemical Research in Toxicology.

Investigators affiliated with a Washington state analytical laboratory analyzed aerosol mixtures produced from 13 commercially available electronic cannabis cartridges. Researchers identified the presence of heavy metals, including copper and nickel, in both vapor and in the oil itself. The authors identified various parts of the cartridges – including heating coils, wicks, metal cores, and mouthpieces – as the sources of the elemental emissions. A higher prevalence of metal contaminants was identified following the use of the cartridges’ heating mechanisms. Researchers identified an inverse relationship between metal contamination and terpene content, but they did not offer any definitive explanation for this phenomenon.

Investigators reported: "[T]his study … has … shown that commercially available electronic cannabis devices (ECD) are a potential source for inhalation exposure to metals. … [C]hromium, copper, nickel, as well as smaller amounts of lead, manganese, and tin migrate into the cannabis oil and inhaled vapor phase, resulting in a possible acute intake of an amount of inhaled metals above the regulatory standard of multiple governmental bodies. … It was shown that leaching after periods of time at ambient or elevated temperatures was responsible for the migration of metals from the ECD into the liquid. … The metal content of vaping aerosols decreased with the addition of terpenes to the cartridge liquid. At this time, the mechanism by which the addition of terpenes reduces these metal emissions is unknown, but future research is being undertaken to establish if this is a phenomenon unique to terpenes or if it is a general trait of less viscous liquids."

Prior analyses of unregulated vapor pen products containing THC have similarly identified the presence of heavy metals and other adulterants. Separate analyses of the aerosol produced by nicotine-filled e-cigarette devices have also detected metal emissions. Metal exposure over time has been linked to a variety of serious health concerns, including lung disease, brain damage, and cardiovascular disease

Full text of the study, "Metals in cannabis vaporizer aerosols: Sources, possible mechanisms, and exposure profiles," appears in Chemical Research in Toxicology.