Overview
Ninety spice samples across ten varieties (ginger, garlic, rosemary, aniseed, negro pepper, nutmeg, green pepper, white pepper, turmeric powder, black pepper) were purchased from three major markets in Accra and analyzed by microwave-digestion ICP-MS for arsenic, iron, zinc, lead, and cadmium. Arsenic and lead in turmeric powder, whole rosemary, and garlic, and lead in ginger, slightly exceeded Codex Alimentarius limits but remained below FAO/WHO permissible levels. All spices showed target hazard quotient (THQ) and hazard index (HI) values below 1, suggesting no acute non-carcinogenic health risk from individual spice consumption at typical Ghanaian ingestion rates, though the authors note the need for ongoing monitoring given long-term bioaccumulation potential.
Key numbers
Analytical method: Agilent 7700 Series ICP-MS; microwave-assisted acid digestion (65–69% HNO₃ and 30–32% H₂O₂ at 170 °C, 50 bar, 45 min). Certified reference material: FAPAS 07340 (Cocoa Powder). CRM recoveries: Pb 103%, As 108%, Fe 99.8%, Zn 101.4%, Cd 93.14%. Values reported as mg/kg (wet weight basis inferred from common conventions; dry weight not explicitly stated in abstract but context suggests as-received powder).
- tAs (total arsenic) range across all spices: not detected to 14.012 mg/kg (14,012 µg/kg); highest in turmeric powder from India.
- Mean tAs range: 0.068 ± 0.052 to 9.831 ± 4.352 mg/kg; turmeric showed highest mean As.
- Pb range: not detected to 3.583 mg/kg (3,583 µg/kg).
- Mean Pb range: 0.100 ± 0.110 to 2.016 ± 0.957 mg/kg; ginger and rosemary had highest Pb means.
- Cd range: 0.02–0.45 mg/kg (20–450 µg/kg).
- Mean Cd range: 0.051 ± 0.017 to 0.156 ± 0.054 mg/kg.
- Zn range: 0.056–0.895 mg/kg; Fe range: 0.022–5.814 mg/kg.
- Turmeric powder, whole rosemary, and garlic: As above Codex limit; turmeric As mean 9.83 mg/kg vs. Codex limit for spices.
- Ginger and rosemary: Pb above Codex limit.
- All THQ/HI < 1 at estimated ingestion rate of 10 g/day/person (body weight 60 kg).
Note: This study reports total arsenic (tAs), not inorganic arsenic (iAs). ICP-MS without HPLC speciation cannot distinguish iAs from organic arsenic species. The high As values in turmeric and other spices represent total arsenic; the proportion as iAs is unknown and would require speciation analysis.
Methods (brief)
Microwave digestion with HNO₃/H₂O₂; Agilent 7700 Series ICP-MS; total metals. No arsenic speciation performed. Ingestion rate for health risk: 10 g/day per person; body weight 60 kg; RfD values used: Cd 0.001, As 0.003, Pb 0.004, Zn 0.3, Fe 0.7 mg/kg/day.
Implications
Certification: Documents elevated total As and Pb in commonly traded spices, particularly turmeric (As), rosemary (As, Pb), garlic (As), and ginger (Pb), purchased in a major West African market hub where spices originate from multiple countries. Relevant to spice ingredient sourcing and HMT&C spice category threshold setting.
Courses: Illustrates that spices, despite their small ingestion volume, can carry substantial heavy metal concentrations; emphasizes the speciation gap (tAs vs. iAs) as a critical limitation of screening studies.
App: Turmeric, rosemary, garlic, and ginger warrant elevated tAs and Pb flags; iAs uncertainty should be communicated to users.
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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. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Change | Description |
|---|---|---|---|
| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |