Overview
Desalew and Mehari quantified ten elements (Ca, Mg, Fe, Zn, Mn, Cu, Ni, Cr, Cd, Pb) in rice grains collected from the three major production regions of Ethiopia (Fogera, Metema, Pawe) and their corresponding field soils, using flame atomic absorption spectroscopy (FAAS). Cadmium, lead, and chromium were all below the limit of quantitation in rice grain samples from all three regions. The study provides useful baseline occurrence data confirming that Ethiopian-grown rice, at least from these three regions, does not appear to accumulate toxic metals at measurable levels under local agricultural conditions, though method sensitivity for heavy metals was limited.
Key numbers
- Sample n: 27 rice grain composite samples (9 per region, each composite of 3 farmer samples, 0.5 kg each)
- Method: FAAS with HNO3/HClO4/H2O2 acid digestion; accuracy 87–113% recovery
- Cd: below LOQ in all samples (LOQ not explicitly stated; inferred <0.1 mg/kg)
- Pb: below LOQ in all samples
- Cr: below LOQ in all samples
- Ni: below LOQ in all samples
- Most abundant element in rice: Mg (414–561 mg/kg dw), followed by Fe (49.4–168 mg/kg dw)
- Fe in rice differed significantly by region: Fogera contained more than double the Fe of the other regions
- Cu in rice from Pawe was less than half that from other regions
- Soil concentrations for all elements were higher than in grain, indicating absence of bioaccumulation
- Only Cu showed a strong positive correlation between soil and grain (r = 0.991); other elements did not correlate significantly
Methods (brief)
FAAS on acid-digested samples. Digestion optimized for reagent volumes (HNO3, HClO4, H2O2), temperature, and time. Three sampling areas per region; composite samples from three different farmers per area. Accuracy validation by certified reference material comparison (87–113%). Loq threshold not explicitly stated for toxic metals; Cd, Pb, and Cr reported as “below the limit of quantitation of the method.”
Implications
Certification: Confirms Ethiopian rice at these three production sites does not exceed measurable Cd/Pb/Cr thresholds under current analytical limits, though method sensitivity may not detect low-level contamination. Baseline data for an underrepresented geography.
Courses: Illustrates geographic variability in rice elemental profiles; contrast with known high-arsenic Asian rice geographies.
App: All toxic metals below LOQ for this origin; app should handle below-LOQ reporting as data gap rather than zero.
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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 |