Overview
Ab Manan and colleagues measured Cu, Zn, Pb, and Ni in oil-palm plantation soil and assessed geo-accumulation index values. This is supply-chain pathway evidence for plantation soil and fertilizer-associated metal loading, not palm-oil occurrence evidence.
Key numbers
The abstract reports concentration ranges of 0.76-2.00 mg kg-1 for Cu, 0.29-1.58 mg kg-1 for Zn, 0.07-0.22 mg kg-1 for Pb, and 0.01-0.05 mg kg-1 for Ni. The authors state that Cu concentrations were higher than the other measured metals and that Cu and Zn accumulation was possibly related to chemical-fertilizer application.
Table 1 reports metal concentrations in mg kg-1 as mean +/- SD:
| Soil sample | Cu | Zn | Pb | Ni |
|---|---|---|---|---|
| Point A | 0.91 +/- 0.13 | 0.46 +/- 0.19 | 0.12 +/- 0.03 | 0.02 +/- 0.007 |
| Point B | 2.00 +/- 0.19 | 1.58 +/- 0.73 | 0.22 +/- 0.04 | 0.05 +/- BDL |
| Point C | 1.18 +/- 0.22 | 0.55 +/- 0.32 | 0.09 +/- 0.02 | 0.02 +/- 0.007 |
| Point D | 1.53 +/- 0.66 | 0.90 +/- 0.37 | 0.12 +/- 0.06 | 0.03 +/- 0.02 |
| Point E | 1.87 +/- 0.23 | 0.85 +/- 0.49 | 0.13 +/- 0.01 | 0.03 +/- 0.007 |
| Point F | 1.37 +/- 0.55 | 0.53 +/- 0.21 | 0.09 +/- 0.04 | 0.04 +/- 0.02 |
| Point G | 1.26 +/- 0.24 | 0.51 +/- 0.03 | 0.09 +/- 0.02 | 0.03 +/- 0.02 |
| Point H | 1.30 +/- 0.46 | 0.76 +/- 0.25 | 0.08 +/- 0.03 | 0.05 +/- 0.007 |
| Point I | 1.29 +/- 0.23 | 0.73 +/- 0.08 | 0.12 +/- 0.02 | 0.04 +/- 0.007 |
| Control | 0.76 +/- 0.34 | 0.29 +/- 0.05 | 0.07 +/- 0.04 | 0.01 +/- BDL |
Table 3 reports Igeo values for the plantation points:
| Soil sample | Cu | Zn | Pb | Ni |
|---|---|---|---|---|
| Point A | 0.24 | 0.32 | 0.34 | 0.40 |
| Point B | 0.53 | 1.09 | 0.63 | 1.00 |
| Point C | 0.31 | 0.37 | 0.27 | 0.40 |
| Point D | 0.40 | 0.62 | 0.34 | 0.60 |
| Point E | 0.49 | 0.59 | 0.37 | 0.60 |
| Point F | 0.36 | 0.37 | 0.26 | 0.80 |
| Point G | 0.33 | 0.35 | 0.25 | 0.60 |
| Point H | 0.34 | 0.53 | 0.23 | 0.94 |
| Point I | 0.34 | 0.51 | 0.34 | 0.74 |
The paper states that all samples showed Igeo values less than 2, indicating uncontaminated to moderately contaminated soil, and that point B showed the highest Igeo values for the measured metals.
Methods (brief)
Soil samples were collected in triplicate using a hand auger from oil-palm plantation points A-I; a control sample came from undisturbed non-agricultural soil. Samples were dried, sieved to 2 mm, digested with nitric acid and hydrogen peroxide, and analyzed by ICP-OES. The paper reports total Cu, Zn, Pb, and Ni in soil, not food or oil concentrations.
Implications
Certification: Do not use these values as palm-oil occurrence data. They are plantation-soil values that can support fertilizer and agricultural-soil pathway discussion.
Courses: Useful concise example of oil-palm plantation soil monitoring and Igeo classification, with point B carrying the highest Cu, Zn, Pb, and Ni values.
App: Context only. The source can inform supplier-pathway questions for plantation soil management, not finished-product scoring.
Wiki pages this source may touch
- Soil-to-plant transfer of heavy metals
- Irrigation water and soil amendments as anthropogenic inputs to cropland
- Lead
- Nickel
- Copper
- Zinc
Verification notes
Recovered from skip:not-food-occurrence under the 2026-06-10 inclusion-by-default rule. The old skip treated oil-palm soil as out of scope because no palm-oil sample was measured. On reading, it is in-scope a3 pathway evidence because it measures metal loading in plantation soil and explicitly discusses fertilizer as a potential source.
Numbers were checked against the abstract, Table 1, Table 3, and the results/conclusion sections of the extracted PDF text. Products and ingredients are intentionally empty.
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.