Overview
Fatai et al. measured Cu, nickel (Ni), Zn, cadmium (Cd), chromium (Cr), and lead (Pb) in African spinach (Amaranthus hybridus) and tomato (Solanum lycopersicum) collected around Ashaka community in Gombe State, Nigeria. The source is direct occurrence evidence for field-grown leafy vegetables and tomatoes from this local context, with African spinach reporting Cd at 0.210 mg/kg and Pb at 0.290 mg/kg. The study is useful for geography-specific context but has limited benchmark value because it reports two vegetable matrices as summary rows rather than sample-level distributions.
Key numbers
- Table 1 reports heavy metal concentrations in mg/kg for African spinach: Cu 0.206, Ni 0.619, Zn 0.231, Cd 0.210, Cr 0.073, and Pb 0.290.
- Table 1 reports heavy metal concentrations in mg/kg for tomato: Cu 0.100, Ni 0.133, Zn 0.229, Cd 0.088, Cr 0.099, and Pb 0.167.
- The paper compares these results with FAO/WHO limits listed as Cd 0.2 mg/kg, Ni 5.0 mg/kg, Cr 2.3 mg/kg, Pb 0.3 mg/kg, and Cu 40 mg/kg; it lists a CPDM Zn limit of 20 mg/kg.
- The authors state that Cd in African spinach exceeded the 0.2 mg/kg FAO/WHO comparison value, while Pb in African spinach was below the 0.3 mg/kg comparison value.
- Table 2 reports daily intake estimates for African spinach: Cu 0.018, Ni 0.053, Zn 0.019, Cd 0.018, Cr 0.006, and Pb 0.024.
- Table 2 reports daily intake estimates for tomato: Cu 0.009, Ni 0.011, Zn 0.019, Cd 0.007, Cr 0.008, and Pb 0.014.
- Table 3 reports health risk index values for African spinach: Cu 0.45, Ni 2.65, Zn 0.063, Cd 18.00, Cr 0.004, and Pb 6.857.
- Table 3 reports health risk index values for tomato: Cu 0.225, Ni 0.55, Zn 0.063, Cd 7.00, Cr 0.005, and Pb 4.00.
Methods (brief)
Fresh African spinach and tomato samples were collected from two locations in Ashaka community, Funakaye Local Government Area, Gombe State, Nigeria. The methods section states that sampling occurred at regular intervals across the plots, then plant materials were separated, washed, dried, ground, homogenized, acid-digested, and analyzed by atomic absorption spectrophotometry using a Perkin Elmer model 2130 instrument. Digestion used a mixed acid system of nitric acid, hydrochloric acid, and sulfuric acid, with final metal concentrations calculated as mg/kg vegetable.
Implications
- Certification: The African spinach row is direct non-US occurrence context for Cd, Pb, Ni, Cr, Cu, and Zn in leafy vegetables; it should not be silently pooled into a US-market benchmark without jurisdictional justification.
- Courses: The paper is a concise teaching example for distinguishing source-reported occurrence values from health-risk-index calculations.
- App: The spinach and tomato rows can support geography-specific alerts for Nigerian field-grown vegetable evidence, with low distribution confidence because sample-level values are not reported.
- Microbiome: Not primary topic.
Related evidence
- Lead
- Cadmium
- Nickel
- Chromium
- Copper
- Zinc
- Spinach
- Tomato
- Leafy Vegetables
- Spinach
- Leafy / Green Vegetables, Other
Update history
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