This Health Canada study measured 18 metals in 50 regulated dried cannabis products and 12 metals in 20 cannabis vaping liquids from the Canadian legal market. The paper provides a probabilistic risk assessment applying European Pharmacopoeia (Ph Eur) permitted daily exposures and USP concentration limits as reference points, with the 50 dried cannabis samples comprising the same regulated product cohort reported in a companion paper by Fiering et al. (2026).
Key numbers
All concentrations are µg/g. Dried cannabis values (Table 1) are medians and maximums across 50 products. Vaping liquid values (Table 2) are medians and maximums across 20 products. [VERIFY table check]
Dried cannabis (Table 1):
| Metal | Median | Maximum | Ph Eur PDE reference (µg/g at 10 g/day) |
|---|---|---|---|
| lead (Pb) | <0.05 | 0.24 | 0.5 |
| cadmium (Cd) | <0.03 | 0.16 | 0.3 |
| total arsenic (tAs) | <0.02 | 0.16 | 0.2 |
| total mercury (tHg) | <0.01 | 0.03 | 0.1 |
| chromium (Cr) (total) | 0.05 | 0.89 | 0.3 |
| nickel (Ni) | 0.08 | 4.69 | 0.6 |
| Cu | 8.65 | 63.97 | 3.0 |
| Mo | 2.11 | 9.93 | 1.0 |
| Ba | <3.00 | 40.68 | n/a |
| V | <0.01 | 0.36 | 0.1 |
Metals below detection in all 50 dried cannabis products: Ag (<0.07), Au (<0.01), Sb (<0.20), Se (<1.30), tin (Sn) (<0.60), Tl (<0.08). Li below detection in most samples (median <0.25, max 0.76 µg/g).
Cannabis vaping liquids (Table 2): selected metals, median/maximum (µg/g):
| Metal | Median | Maximum |
|---|---|---|
| chromium (Cr) | 0.294 | 21.70 |
| nickel (Ni) | 0.521 | 54.70 |
| Cu | 0.569 | 485.00 |
| lead (Pb) | 0.028 | 0.628 |
| cadmium (Cd) | <0.0054 | 0.0077 |
| total arsenic (tAs) | 0.006 | 0.100 |
| Fe | 1.694 | 84.83 |
| Zn | 1.532 | 310.00 |
The authors note that chromium, nickel, copper, iron, and zinc in vaping liquids far exceed dried cannabis concentrations, consistent with metal leaching from device heating coils and other hardware components.
The risk assessment found that most metals in dried cannabis remain below Ph Eur PDEs at typical consumption rates. Chromium, nickel, and copper in vaping liquids pose greater risk relative to inhalation PDEs than the same metals in dried cannabis.
Methods (brief)
ICP-MS; 18 metals for dried cannabis, 12 metals for vaping liquids. LOD values are indicated as detection-limit markers for below-detection entries. CRM data not stated. Ph Eur permitted daily exposures and USP 232 concentration limits used as reference benchmarks (not Canadian regulatory requirements, which the paper notes do not exist as a uniform federal standard).
Evidence fitness
This study provides median and maximum metal concentrations for 50 regulated Canadian dried cannabis products and 20 vaping liquids. The dried cannabis data are the strongest occurrence values for the regulated legal Canadian market and support occurrence profiling for lead, cadmium, total arsenic, total mercury, total chromium, and nickel. Copper and molybdenum medians substantially exceed USP 232 inhalation limits but both are essential elements; the authors note the limits were designed for pharmaceutical impurities, not naturally occurring plant constituents. Vaping liquid data belong to the cannabis-vape-hardware routing. Arsenic speciation is not reported; total arsenic values cannot substitute for inorganic arsenic.
Limitations
The 50 regulated samples overlap with the legal cohort in Fiering et al. (2026); these two papers should not be pooled as independent datasets. Detailed cultivar, region, and soil provenance are not reported. No CRM recovery data provided.
Related evidence
- Cannabis flower / dried herb
- Vape cartridges and hardware
- Lead
- Cadmium
- Arsenic
- Mercury
- Chromium
- Nickel
Update history
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