Overview
Altmaier describes an ICP-MS workflow for arsenic, cadmium, mercury, and lead in Cannabis sativa plant material, using three industrial-hemp flower varieties purchased from a German drugstore. The paper is a trade-publication technical feature rather than a peer-reviewed market survey, but it prints concentration tables for dried hemp flowers and separated plant parts. Chromium and nickel values are also reported as milling-contamination diagnostics, so those values should not be pooled with product occurrence without preserving the milling method.
Key numbers
Table IV reports heavy-metal content of three cannabis varieties after four grinding procedures. Units are µg/g. Arsenic and mercury are not speciated, so this page records them as total arsenic (tAs) and total mercury (tHg).
| Matrix / preparation set | tAs | Cd | tHg | Pb | Cr | Ni |
|---|---|---|---|---|---|---|
| Finola hemp flowers, four preparations | 0.1 µg/g in all four preparations | < 0.1 µg/g in all four preparations | < 0.1 µg/g in all four preparations | 0.6-0.7 µg/g | 0.3-0.4 µg/g by RP/MP; 12 µg/g by both cryo-mill preparations | 0.8-1.1 µg/g by RP/MP; 2.0-2.1 µg/g by cryo-mill preparations |
| Santhica hemp flowers, five preparations | < 0.1 µg/g in all five preparations | < 0.1 µg/g except MP at 0.1 µg/g | < 0.1 µg/g in all five preparations | 0.3-0.5 µg/g | 0.2-0.3 µg/g by RP/MP/KM; 2.5-3.6 µg/g by cryo-mill preparations | 0.4-1.7 µg/g by RP/MP/KM; 0.6-0.7 µg/g by cryo-mill preparations |
| Felina hemp flowers, five preparations | 0.1 µg/g by RP; < 0.1 µg/g by the other four preparations | < 0.1 µg/g in all five preparations | < 0.1 µg/g in all five preparations | 0.5-1.0 µg/g | 0.3-0.6 µg/g by RP/MP/KM; 3.7-4.3 µg/g by cryo-mill preparations | 0.5-0.6 µg/g by RP/MP/KM; 0.7 µg/g by both cryo-mill preparations |
The Results section summarizes the same table by stating that mercury was below LOD in all samples, only one of 14 samples had cadmium (Cd) above the detection limit (0.1 µg/g), five samples contained arsenic (As) close to the LOD (0.1 µg/g), and detected lead (Pb) ranged from 0.3 to 1.0 µg/g.
Table V reports Santhica plant parts without grinding, in duplicate:
| Santhica plant part | tAs | Cd | tHg | Pb |
|---|---|---|---|---|
| Stems | < 0.1 / < 0.1 µg/g | < 0.1 / < 0.1 µg/g | < 0.1 / < 0.1 µg/g | 0.4 / 0.4 µg/g |
| Seeds | < 0.1 / < 0.1 µg/g | < 0.1 / < 0.1 µg/g | < 0.1 / < 0.1 µg/g | < 0.1 / < 0.1 µg/g |
| Leaves | < 0.1 / < 0.1 µg/g | < 0.1 / < 0.1 µg/g | < 0.1 / < 0.1 µg/g | 0.4 / 0.4 µg/g |
The paper states that cryo milling used stainless-steel equipment and produced elevated chromium (Cr) in all cryo-ground samples; elevated nickel (Ni) relative to rolling-pin and mortar/pestle milling appeared only in the Finola sample. Knife milling used titanium blades and did not affect Cr or Ni content in the same way.
Methods (brief)
Three Cannabis sativa industrial-hemp varieties, Finola, Felina, and Santhica, were sold as dried hemp flowers in 25 g batches under German THC rules (<0.2%). Aliquots were prepared by rolling pin, mortar and pestle, knife mill, and cryo ball mill. A second Santhica experiment manually separated seeds, leaves, and stems and digested them without a preceding grinding step. The method used microwave nitric-acid digestion, indium internal standard, standard-addition calibration with CRM heavy-metal mixes, and ICP-MS. Table II lists the digestion and ICP-MS conditions; Table III reports recovery rates for As, Cd, mercury (Hg), and Pb of 90-110% across the three varieties.
Implications
The paper provides limited occurrence context for dried hemp flowers and plant parts, plus a useful method warning that sample-preparation hardware can inflate Cr and sometimes Ni. The big-four values may inform hemp/cannabis botanical context at C-tier, but Cr and Ni values need milling-method qualifiers before any downstream use.
Related evidence
- Ingredient class — botanicals/herbs/traditional formulas
- Herbal botanicals
- Arsenic, Total
- Cadmium
- Mercury, Total
- Lead
- Chromium
- Nickel
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 |