Andrew Waye, who’s in charge of the research program at the Health Canada Office of Cannabis Science and Surveillance, presented the results of the study at the meeting. “Cannabis vapes are newly regulated products in Canada, so we don’t yet have much scientific data about them,” Waye said in a press release. “This is an opportunity for us to look at some of the questions concerning the risks and unknowns of cannabis vapes.” Lighting a cigarette combines tobacco (the fuel) and oxygen to begin a combustion process that burns through the tobacco.

The process of vaping doesn’t utilize a combustion process, and instead heats the liquid until it becomes an inhalable vapor. Between cigarettes and vaping, vaping is often seen as safer, but researchers cautioned this opinion due to the presence of metals that can still be present in the vapor that is inhaled. The study primarily focused on whether or not cannabis vapes in particular also contained nano-sized metals. Using 41 different cannabis vape liquids (20 of which were legal products, and 21 were illegal samples provided by the Ontario Provincial Police), researchers utilized mass spectrometry to find and analyze a variety of contaminants.

  Researchers worked with Zuzana Gajdosechova, who works at the Metrology Research Centre of the National Research Council of Canada, to analyze the samples and determine if they contained any of 12 metals that can be viewed via electron microscopy. The press release explained that metals such as arsenic, mercury, and cadmium were present, but within acceptable limits. However, some illegal samples contained more lead than is legally permitted. “The presented data from legally purchased and illegal cannabis vape devices showed mass fractions of Pb above the currently established tolerance limits in several of the vape liquids analyzed, particularly in the illegal samples where Pb [lead] concentrations were up to 100 times higher than the limit,” the authors wrote.

“Additionally, the measured mass fractions of toxic metals such as Cr [chromium], Cu [copper], Ni [nickel], and Co [cobalt], as well as the essential metals Zn [zinc] and Mn [manganese] that have known inhalation toxicity, add to the existing evidence that long-term vaping may carry risks to health.” The samples were taken from vapes that were less than six months old and had never been opened or used. “The evidence strongly suggests that metal contamination can come from the device when it’s produced, and not from the heating of the coils,” Gajdosechova said.

“But depending on the quality of the device, the contamination may be increased by that heating.” The study showed that the most common heating elements usually include nichrome, copper-plated brass, and kanthal, while the metal components of atomizers (the wick and coil in a vape pen) are made from stainless steel and tin, and lead is used as a solder. This prompted researchers to reconsider testing procedures in Canada. “If contamination is happening when the device is assembled, you should be testing at that stage rather than earlier,” said Waye.

Through single particle inductively coupled plasma mass spectrometry, the research team also found that metal particles were nano-sized. “Some nano-sized metal particles are highly reactive and potentially harmful,” said Gajdosechova. The next step would be to analyze how much of those harmful, nano-sized metals are transferred into the vapor. This could reveal even more about the potential harm of metals entering the lungs when inhaled. “Different types of cannabis products present different risks,” said Waye.

“Our research doesn’t answer whether vaping is riskier than smoking, it just underlines that the risks may be different. Previously uncharacterized risks with cannabis vaping are still being identified.” Research conducted by New York’s Columbia University last year found that cannabis and tobacco consumers had higher percentages of lead and cadmium in their blood and urine compared to non-users of tobacco and cannabis. Scientists explained that long term exposure to lead and cadmium could lead to health issues such as cardiovascular disease, chronic obstructive pulmonary disease, cognitive impairments, or an increased risk of cancer.

“We found overall associations between internal metal levels and exclusive marijuana use, highlighting the relevance of marijuana for metal exposure and the importance of follow-up studies to identify the long-term implications of these exposures,” researchers said in their conclusion. They also called for more research in order to assess the presence of other contaminants and health impacts to protect the general public. Read less