Joseph and colleagues measured seven metals in kenaf, chili pepper, tomato and spinach plant parts, with associated soil and irrigation water from Gobbiya Dam in Nigeria. The paper separates edible leaves or fruits from roots and stems. Its concentration tables are preserved independently of several inconsistent safety comparisons and a soil-index calculation that uses water standards.
Key numbers
Tables 1–4 (PDF pp. 4–6) report mean ± SD with n=3 replicate measurements. Selected edible parts are shown below in mg/kg of oven-dried material; the structured evidence retains all sampled organs and the repeated soil/water observations once. BDL means below an unreported detection limit.
| Plant part | tAs | Fe | Cd | Cu | Cr | Pb | Ni |
|---|---|---|---|---|---|---|---|
| Kenaf leaves | 0.018 ± 0.015 | 0.536 ± 0.076 | 0.064 ± 0.004 | BDL | 0.082 ± 0.017 | 0.051 ± 0.006 | 0.181 ± 0.105 |
| Chili pepper fruits | 0.032 ± 0.004 | 1.358 ± 0.114 | 0.295 ± 0.307 | 0.347 ± 0.036 | 0.078 ± 0.011 | 0.048 ± 0.007 | 0.217 ± 0.083 |
| Tomato fruits | 0.055 ± 0.001 | 0.563 ± 0.050 | 0.084 ± 0.004 | 0.064 ± 0.053 | 0.101 ± 0.010 | 0.043 ± 0.006 | 0.267 ± 0.051 |
| Spinach leaves | 0.025 ± 0.011 | 1.345 ± 0.104 | 0.075 ± 0.002 | 0.242 ± 0.028 | 0.079 ± 0.008 | 0.052 ± 0.004 | 0.298 ± 0.020 |
Tables 5–8 retain organ-specific bioaccumulation factors, leaf/root translocation factors, the source’s contamination-factor calculation, and profile correlations as separate statistical records. They are not additional concentration samples.
Methods (brief)
Vegetables were washed, oven-dried at 80°C for 24 hours, pulverized and digested with a sulfuric/perchloric/nitric-acid mixture. Soil was collected at 0–20 cm, composited, dried and digested separately. Acid-preserved water was digested with nitric acid. Atomic absorption spectrometry measured arsenic (As), Fe, cadmium (Cd), Cu, chromium (Cr), lead (Pb) and nickel (Ni) without species separation. The source reports triplicate measurements and SD, ANOVA and a post-hoc comparison, but no instrument-specific LODs, certified-reference results or field sample count.
Implications
The organ-resolved dry-weight values support local occurrence and irrigation-pathway analysis. Roots, stems and non-edible leaves are retained as pathway context rather than assigned to edible-product distributions. Broad leafy-vegetable and herb/spice ingredient routes retain kenaf and chili identity in the structured record without substituting a named cultivar.
Evidence Fitness: EF-3; measured organ-level occurrence summaries with limited sampling and analytical quality documentation. Transfer metrics and correlations are source-model outputs; the soil contamination-factor calculation is methodologically unsuitable for an independent soil-hazard claim.
Related evidence
- Leafy / Green Vegetables, Other
- Non-Root Vegetables
- Leafy Vegetables
- Spinach
- Tomato
- Herbs And Spices
- Irrigation water and soil amendments as anthropogenic inputs to cropland
- Arsenic, Total
- Iron
- Cadmium
- Copper
- Chromium
- Lead
- Nickel
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