Overview
Orobator compared lead (Pb), cadmium (Cd), Co, chromium (Cr), nickel (Ni), arsenic (As), and V in unburnt and burnt oil-palm plantation topsoil in Edo State, Nigeria. This is supply-chain pathway and source-attribution context for plantation soil disturbance, not palm-oil occurrence evidence.
Key numbers
The study collected 20 topsoil samples from 0-15 cm depth: 10 from an unburnt oil-palm plantation and 10 from an adjacent burnt oil-palm plantation. Table 1 reports higher means for every measured metal in the burnt plantation soil.
Table 1 concentrations are reported in mg kg-1:
| Soil parameter | Unburnt range | Unburnt mean | Unburnt SD | Burnt range | Burnt mean | Burnt SD | p-value | WHO limit |
|---|---|---|---|---|---|---|---|---|
| lead (Pb) | 10.38-14.04 | 11.87 | 1.37 | 10.41-22.40 | 15.15 | 4.09 | 0.01* | 85.00 |
| cadmium (Cd) | 0.08-0.19 | 0.15 | 0.03 | 0.15-0.33 | 0.20 | 0.06 | 0.00* | 0.80 |
| Co | 2.05-4.61 | 3.63 | 0.77 | 3.72-8.20 | 5.09 | 1.48 | 0.00* | 24.00 |
| chromium (Cr) | 2.61-5.89 | 4.62 | 0.97 | 4.70-10.50 | 6.52 | 1.90 | 0.00* | 100.00 |
| nickel (Ni) | 2.20-4.98 | 3.93 | 0.83 | 4.01-8.50 | 5.42 | 1.54 | 0.00* | 35.00 |
| arsenic (As) | 1.28-2.87 | 2.26 | 0.47 | 2.30-5.12 | 3.19 | 0.95 | 0.00* | 0.80 |
| V | 0.85-2.01 | 1.52 | 0.34 | 1.55-3.42 | 2.12 | 0.62 | 0.00* | Not specified |
The abstract states that the burnt oil-palm plantation had higher Pb 15.15 mg kg-1, Cd 0.20 mg kg-1, Co 5.09 mg kg-1, Cr 6.52 mg kg-1, Ni 5.42 mg kg-1, As 3.19 mg kg-1, and V 2.12 mg kg-1. The conclusion states that higher As concentrations were observed in soils from both oil-palm plantations compared with the permissible limit.
The paper attributes higher burnt-soil values to bushfire effects including ash deposition, biomass burning, and post-fire mobilization. It also discusses fertilizer, pesticides, herbicides, and agrochemical use as possible contributors to metal presence in unburnt plantation soil.
Methods (brief)
The study used adjacent unburnt and burnt oil-palm plantations in Okunuvbe community, Edo State. A grid sampling design and systematic random sampling produced 10 topsoil samples per plantation. Pb, Cd, Co, Cr, Ni, As, and V were measured by Perkin-Elmer Analyst 300 Atomic Absorption Spectrophotometer and reported in mg kg-1. Student t-tests compared unburnt and burnt plantation means.
Related evidence
- Soil-to-plant transfer of heavy metals
- Source attribution and environmental burden apportionment
- Arsenic
- Cadmium
- Lead
- Chromium
- Nickel
- Vanadium
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.