This PRISMA-ScR scoping review synthesized nine primary studies on heavy metals in cannabis vaping (CV) liquids and aerosols. It identified nickel, chromium, lead, copper, manganese, cobalt, cadmium, zinc, and gold as the metals most frequently detected in cannabis vapes, with device components (battery contacts, heating coils, mouthpieces) as the primary metal sources. The paper does not contain primary concentration data beyond syntheses from cited studies.
Key numbers
From the included studies (Table 1 synthesis, not original measurements): [VERIFY table check]
Counterfeit cannabis cartridges: copper, nickel, lead, and silicon each reported above 660 ppm in some devices. EVALI-associated vaping products: lead approximately 11.1 µg/g, nickel approximately 477 µg/g, copper approximately 150 µg/g, manganese approximately 120 µg/g. Device components identified as metal sources: battery contacts (nickel, chromium), heating coil (nickel-chromium alloys), mouthpieces (copper, manganese, nickel, lead, tin).
The review notes that vaping was associated with elevated urinary chromium, copper, nickel, and manganese in human biomonitoring studies relative to non-vaping controls. Cobalt, cadmium, and copper are reported as transportable to aerosol as nanoparticles.
Methods (brief)
PRISMA-ScR systematic scoping review; 80 initial records, 51 after deduplication, 9 included at full-text. No meta-analysis; narrative synthesis only. Health implication sections draw on IARC carcinogenicity classifications and organ-system toxicology reviews.
Evidence fitness
This review provides a useful synthesis of the primary literature on metal contamination of cannabis vaping products and devices. It is relevant to the cannabis-vape-hardware routing. It does not contain original measurements of cannabis flower or inflorescence and is not relevant to dried cannabis flower occurrence profiling.
Limitations
9 studies included; small base of primary literature. Narrative synthesis without quantitative pooling. Metal concentrations cited in Table 1 are from individual studies that may not be representative of the broader market.
Related evidence
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