Altmaier 2021 - big-four metals in cannabis flowers
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 tAs and 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 Cd above the detection limit (0.1 µg/g), five samples contained As close to the LOD (0.1 µg/g), and detected 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 Cr in all cryo-ground samples; elevated 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, 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.
Wiki pages this source may touch
- supplements-botanicals-herbs
- herbal-botanicals
- arsenic-total
- cadmium
- mercury-total
- lead
- chromium
- nickel
Verification notes
- Identity checks before writing found no existing source page for the article title, raw handle
MFK_big-four-analysis-cannscitech, or cite keyaltmaier2021-cannabis-big-four-metals. - DOI check: no DOI was found in the PDF text or work-list row. The article page and PDF identify it as Cannabis Science and Technology 4(2), 24-29 (2021), so
no_doi_assigned: trueis used. - All Key numbers were rechecked against
/tmp/hmi-june9-081.txtextracted withpdftotext -layout, especially Tables IV and V. - Speciation check: As and Hg are not speciated; the page uses tAs and tHg. No iAs or MeHg values are inferred.
- Units are preserved as
µg/g; no conversions were performed. - Evidence tier: C, because this is a trade-publication technical feature with three hemp-flower varieties, not a peer-reviewed occurrence survey.
- Brand firewall: the source names cultivar/variety labels (Finola, Felina, Santhica), not sampled commercial brands. The German drugstore purchase channel is retained as sample-frame context without naming a retailer.
- Missing slug note: the taxonomy snapshot has no exact hemp/cannabis product or ingredient slug. Frontmatter uses broad
[[ingredients/herbal-botanicals]]and[[products/supplements-botanicals-herbs]], with hemp/cannabis retained only as matrix descriptors.
Page history
The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Description |
|---|---|---|
| 4039d20 | 2026-06-10 | scope: broaden ingest to the full upstream+downstream literature (marine, atmospheric, attribution, exposure, toxicology) — inclusion is the default |