Overview
Islam et al. measured proximate composition, essential minerals, and heavy metals in five spices (red chili, turmeric, coriander, black cumin, bay leaves) from local markets in Northern Bangladesh using graphite furnace atomic absorption spectrometry (GFAAS). Critical species note: the paper’s “black cumin” refers to Nigella sativa (Ranunculaceae family), not Cuminum cyminum (Apiaceae). The two are unrelated plants despite sharing the common name “cumin” in some South Asian contexts. Accordingly, this paper contains no Cuminum cyminum data and cannot be cited for cumin (Cuminum cyminum) heavy-metal values. The paper is retained in the HMI library because it documents Nigella sativa contamination levels in Bangladeshi markets and provides regional spice contamination context.
Key numbers
Heavy metal concentrations (Table 2, mg/kg, dry weight, GFAAS, mean +/- SD, n=9 per spice):
| Metal | Red chili | Turmeric | Coriander | Black cumin (Nigella sativa) | Bay leaf |
|---|---|---|---|---|---|
| lead (Pb) | 0.24 +/- 0.003 | 0.89 +/- 0.003 | 0.15 +/- 0.003 | 0.11 +/- 0.003 | 0.54 +/- 0.003 |
| cadmium (Cd) | 0.22 +/- 0.003 | 0.004 +/- 0.002 | 0.01 +/- 0.003 | 0.05 +/- 0.003 | 0.03 +/- 0.002 |
| arsenic (As) | 0.15 +/- 0.002 | 0.005 +/- 0.003 | 0.004 +/- 0.002 | 0.02 +/- 0.003 | 0.01 +/- 0.03 |
| mercury (Hg) | 0.17 +/- 0.003 | 0.20 +/- 0.003 | 0.21 +/- 0.003 | 0.21 +/- 0.002 | 0.25 +/- 0.003 |
| tin (Sn) | 0.85 +/- 0.002 | 0.17 +/- 0.003 | 0.41 +/- 0.003 | 1.94 +/- 0.003 | 0.51 +/- 0.003 |
| Fe | 117.87 +/- 0.002 | 248.25 +/- 0.03 | 18.61 +/- 0.003 | 90.2 +/- 0.003 | 274.92 +/- 0.003 |
| Cu | 9.43 +/- 0.003 | 4.72 +/- 0.003 | 3.55 +/- 0.003 | 14.78 +/- 0.003 | 4.94 +/- 0.003 |
| nickel (Ni) | 2.28 +/- 0.003 | 2.49 +/- 0.003 | 0.59 +/- 0.01 | 6.12 +/- 0.003 | 2.78 +/- 0.003 |
| Mg | 1390.29 +/- 0.37 | 2066.24 +/- 0.03 | 301.78 +/- 0.003 | 1930.82 +/- 0.03 | 931.14 +/- 0.002 |
Species disambiguation:
- “Black cumin” in this paper = Nigella sativa (family Ranunculaceae), from the Table 1 species identification
- Cuminum cyminum (true cumin, family Apiaceae) was not studied in this paper
Methods (brief)
GFAAS on microwave-digested samples (0.5 g in Teflon vessel with 7 mL concentrated HNO3 and 1 mL HClO4, radiated for 20 min). Filtered through Whatman 0.45 um, transferred to 50 mL flasks with 1% HNO3. Statistics: One-way ANOVA, Tukey HSD, R Studio 1.4.1717 (R 4.1.0).
Implications
Species note for cumin page: This paper documents that “black cumin” in Bangladeshi market and academic contexts means Nigella sativa. The cumin.md ingredient page should note this naming ambiguity explicitly. The lead (Pb) (0.11 mg/kg), cadmium (Cd) (0.05 mg/kg), and other values for Nigella sativa in this paper are not applicable to Cuminum cyminum contamination profiles and should not be incorporated into the cumin occurrence table.
Routing: This source page routes to herbs-and-spices as a broad-spice category source, not to cumin specifically, to avoid species confusion.
Related evidence
Update history
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