Rahman et al. 2021 - Dhaka turmeric heavy metals
Rahman et al. measured eight metals in nine turmeric samples from Dhaka and Savar, Bangladesh: unpacked bulk powder from three local markets, packed commercial turmeric powder from three companies, and raw turmeric from three local farmlands. The paper is direct occurrence evidence for turmeric powder and raw turmeric, with one unpacked bulk sample exceeding the authors’ cited lead comparator. The figures contain the full per-sample profiles; the prose provides several exact maxima/minima and compliance statements.
Key numbers
Concentrations are reported in ppm, equivalent to mg/kg for these solid spice samples.
| Metal | Source-reported result |
|---|---|
| Pb | Highest 12.3469 ppm in unpacked-3 bulk turmeric; lowest 0.1263 ppm in packed-2. The unpacked-3 value exceeded the authors’ cited 6 ppm WHO comparator. |
| Cd | All nine samples were below the authors’ cited 0.1 ppm comparator. |
| Cr | Packed branded samples had no detected chromium; all unpacked and raw samples were within the authors’ cited 100 ppm comparator. |
| tAs | All samples were below the authors’ cited 1.4 ppm comparator. |
| Zn | Highest 2.3307 ppm in unpacked-2; lowest 0.8425 ppm in packed-2; all were within the cited 100 ppm comparator. |
| Fe | Highest 9.7885 ppm in unpacked-3; lowest 6.5201 ppm in raw-2; all were within the cited 300 ppm comparator. |
| Cu | Highest 8.8268 ppm in raw-1; lowest 3.2694 ppm in packed-1; all were within the cited 50 ppm comparator. |
| Mn | Highest 13.5391 ppm in unpacked-2; lowest 0.5377 ppm in packed-2; all were within the cited 100 ppm comparator. |
The authors state that heavy-metal concentrations were generally lower in packed turmeric powders than in unpacked bulk powders. They also report the raw-turmeric decreasing order as Cu > Fe > Mn > Zn > Pb > Cr > Cd > As.
Methods (brief)
The study collected three unpacked bulk turmeric powders from Dhaka local markets, three packed commercial turmeric powders, and three raw turmeric samples from Savar-area farmlands. Raw turmeric was dried and ground; all spice samples were dried at 65 degrees C for 48 hours before nitric-perchloric acid digestion. Lead, cadmium, chromium, arsenic, zinc, iron, copper, and manganese were measured by atomic absorption spectroscopy using standard solutions and reagent blanks. The authors performed triplicate digestion for each sample.
Implications
Certification: This source contributes Bangladesh-market turmeric occurrence evidence, especially for lead in unpacked bulk turmeric powder. The source should be stratified by unpacked bulk, packed powder, and raw turmeric rather than pooled blindly.
Courses: The paper is useful for teaching processing/market-channel differences in spice contamination, because the highest lead result was in an unpacked bulk powder.
App: Route to turmeric and spices. Do not expose the packed-company identities because the page can preserve the source’s market-channel finding without brand-level presentation.
Microbiome (if applicable): The paper does not study microbiome outcomes.
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Verification notes
The PDF title, byline, DOI, year, journal, sample frame, methods, and source-reported numeric maxima/minima were read from the auto-fetched PDF. Figures 1-3 contain additional plotted per-sample values, but the text layer does not preserve all plotted numbers cleanly; this page records exact values stated in prose and keeps the rest as qualitative comparator statements. The source reports arsenic and chromium without speciation, so these values must not substitute for inorganic arsenic or Cr(VI). Audit note: turmeric-powder is retained as an established matrix-map label used by sibling turmeric source pages and data/evidence/matrix-to-product-map.json.
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 |
|---|---|---|
| 26f8654 | 2026-06-03 | audit: helcom2017-core-indicator-metals-baltic [promoted] |