Overview
Zerihun et al. measured calcium, zinc, nickel, copper, cadmium, lead, and total chromium in Cannabis sativa L. leaves collected from four regions of Ethiopia. The samples were dried and reported on a dry-weight basis. Chromium was measured as total chromium; the paper explicitly says it was not possible to know the specific chromium form in the leaves, so no Cr(VI) value is inferred.
Key numbers
Table 7 reports mean concentrations as mean ± SD, n = 9, μg/g dry weight.
| Metal | Butajira (SNNP Region) | Metema (Amhara Region) | Sheshemene (Oromia Region) | Mekelle (Tigray Region) |
|---|---|---|---|---|
| Ca | 868 ± 71 μg/g dry weight | 1,511 ± 53 μg/g dry weight | 657 ± 76 μg/g dry weight | 1,210 ± 130 μg/g dry weight |
| Zn | 377 ± 20 μg/g dry weight | 315 ± 9.8 μg/g dry weight | 380 ± 43 μg/g dry weight | 321 ± 15 μg/g dry weight |
| nickel (Ni) | 149 ± 19 μg/g dry weight | 124 ± 13 μg/g dry weight | 162 ± 14 μg/g dry weight | 172 ± 18 μg/g dry weight |
| Cu | 122 ± 14 μg/g dry weight | 141 ± 16 μg/g dry weight | 176 ± 23 μg/g dry weight | 165 ± 16 μg/g dry weight |
| cadmium (Cd) | 3.2 ± 0.2 μg/g dry weight | 3.7 ± 0.4 μg/g dry weight | 4.7 ± 0.3 μg/g dry weight | 3.4 ± 0.2 μg/g dry weight |
| lead (Pb) | 8.3 ± 0.9 μg/g dry weight | 10.2 ± 1.6 μg/g dry weight | 7.9 ± 0.3 μg/g dry weight | 9.6 ± 0.7 μg/g dry weight |
| chromium (Cr) | 3.9 ± 0.6 μg/g dry weight | 7.6 ± 1.3 μg/g dry weight | 3.6 ± 0.2 μg/g dry weight | 3.8 ± 0.3 μg/g dry weight |
The abstract and conclusion summarize the same dry-weight ranges as Ca 657-1,511, Zn 321-380, nickel (Ni) 124-172, Cu 122-176, cadmium (Cd) 3-10 in the abstract but 3.2-4.7 in the Table 7 and conclusion, lead (Pb) 8-10 in the abstract but 7.9-10.2 in Table 7 and the conclusion, and chromium (Cr) 4-8 in the abstract but 3.6-7.6 in Table 7 and the conclusion. This page uses the Table 7 values for the occurrence table and records the abstract rounding as a source summary only.
Table 5 gives method detection limits in μg/g dry weight: Ca 25, Cr 1, Ni 8, Cu 19, Zn 31, Cd 0.4, and Pb 6.0.
Table 6 reports recovery-test percentages: Ca 92.9, Cr 100, Ni 97.3, Cu 102.5, Zn 91.7, Cd 87.5, and Pb 90.5.
Methods (brief)
Leaves were washed with tap water and deionized water, sun-dried until constant weight, ground, and sieved. For each bulk sample, 0.5 g of dried homogenized powder was digested with 10 mL of HNO3:HClO4 at 9:1 (v/v) at 300°C for 4:00 h, diluted to 25 mL, and analyzed by flame atomic absorption spectrometry. Calibration curves used external standards and three replicate determinations for each sample and standard; reagent blanks were digested in parallel.
Implications
The source provides small-n, dry-weight occurrence context for cannabis leaves used as botanical raw material in Ethiopia. It is not a finished-product market survey, and the regional means should not be pooled with finished cannabis-derived oils, edibles, or topical products without preserving the matrix and basis. The total chromium values should remain total chromium context only.
Related evidence
- Ingredient class — botanicals/herbs/traditional formulas
- Herbal botanicals
- Cadmium
- Lead
- Chromium
- Nickel
- Copper
- Zinc
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git.
| Commit | Date | Change | Description |
|---|---|---|---|
| b01ec52c31 | 2026-08-04 | major | 1 section added |
| 3171d069e3 | 2026-08-02 | major | 1 section added |
| 90a2f9a38e | 2026-07-30 | major | 1 section added and 1 removed; narrative text revised |
| eaa8eeeedf | 2026-07-27 | major | 1 section added |
| 50de6ab217 | 2026-07-27 | minor | Narrative text revised |