Heavy Metals in Cannabis Vapes and Their Health Implications-A Scoping Review.

Cannabis vaping involves the vaporization of cannabis vape (CV) liquid via a vape pen made of metallic and nonmetallic parts. Recently, various metal contaminants that originate from cannabis, as well as the vape liquid packaging device, were reported in CV liquids and aerosols. Heavy metal exposure from CVs is associated with various health afflictions and should be regulated. This scoping review intends to investigate the literature on heavy metal releases from CVs and their impact on health. This review was conducted according to the PRISMA-ScR scoping review guidelines. Initial search in electronic databases such as Medline (PubMed), Scopus, Embase, and Web of Science yielded nine studies published until February 2024. The metals released from CVs, the variables influencing their leaching, and any documented adverse health impacts were recorded. Findings revealed that the structural elements of the CVs leached metals such as nickel (Ni), chromium (Cr), lead (Pb), cobalt (Co), cadmium (Cd), and copper (Cu), which were transported into the aerosol as tiny particles. Several factors, including the structural integrity of the device components, device age, operating temperature, vape liquid pH, and viscosity cutting agents in the vape liquid, caused metal dissolution. Even though none of the studies evaluated the direct health impact of these metals, they proposed that they may affect multiple body organs, specifically the lungs, where they were associated with electronic vaping device use-associated lung injury (EVALI). These metals might expedite the transformation of vitamin E acetate into ketenes, which are associated with EVALI. We can conclude that heavy metals beyond the regulatory guidelines are released from CVs and have negative health consequences. Further research is required to improve the CV design elements to lower the metal leaching. Additionally, disclosing the CV packaging contents to consumers is essential to prevent possible health risks.