Andrew Waye, Office of Cannabis Science and Surveillance, Health Canada, and colleagues have found that toxic nano-sized metal particles may be present in cannabis vaping liquids even before the vaping device is heated, and the effect is worse in unregulated products.
A vaping device heats a liquid until it evaporizes into an inhalable vapor. Unlike smoking, vaping does not involve a combustion reaction that produces harmful by-products. It is, therefore, often considered a safer method of consuming cannabis or nicotine. However, research on nicotine vapes has shown that the metal components that heat the vape liquid can release harmful elemental metals such as nickel, chromium, and lead, which can then enter the aerosol and build up in the user’s body.
The team collected 41 samples of cannabis vape liquids (20 legal, regulated samples from the Ontario Cannabis Store and 21 samples from the illicit market provided by the Ontario Provincial Police) and analyzed them for the presence of twelve metals using mass spectrometry. The team verified the results using techniques such as scanning electron microscopy.
While some metals, such as arsenic, mercury, and cadmium, were within the generally accepted tolerance limits for cannabis products, others were detected in very high concentrations. For example, some unregulated samples contained 100 times more lead than the regulated samples, far exceeding the generally accepted tolerance limit.
This metal contamination was found in the liquid of cannabis vapes that had never been used and were less than six months old. The researchers assume that the metal contamination originates from the device itself and not from the heating of the coils. However, depending on the quality of the device, the contamination may be increased by the heating.
Vapes from the same production batch could contain different amounts of metal contamination. This may affect testing procedures, such as Canadian regulations, for example, require that samples be representative of the entire batch and that testing be done at or after the last step where contamination may occur.
Using inductively coupled plasma mass spectrometry, the researchers found many nano-sized particles. In the future, the team would like to find out how many of the metal particles get into the vape aerosol and thus into the lungs of users. This effect has been demonstrated in nicotine vapes, and the researchers hypothesize that it may also be the case with cannabis vaporizers.
Overall, the researchers say that different types of cannabis products pose different risks. The research cannot say whether vaping is riskier than smoking, but that the risks may be different. While there is not necessarily one “safe” way to consume these products, this research shows that regulation can help make cannabis products safer overall, the researchers say.
- Use of advanced imaging techniques for the identification and analysis of metal particles in unused legal and illegal cannabis vaping products,
Zuzana Gajdosechova, Andrew Waye (Presenter), Joshua Marleau-Gillette, Matthew Turnbull, Duane Petts; Simon Jackson, Ashley Cabecinha, Guru Prasad Katuri, Dharani Das, Kaela Coleman, Ivana Kosarac, Hanan Abramovici, Jeremy Melanson,
Presented at ACS Spring 2024, New Orleans, LA, USA, on March 19, 2024.
