A laboratory trial treated chromium-spiked silty clay soil collected near Nilore, Islamabad. The authors reported 44.58% chromium removal over 24 hours, but the recovered quantities do not close the initial mass balance and the denominator includes native chromium whose oxidation state was not established.
Key numbers
| Measurement | Reported result | Source |
|---|---|---|
| Initial bulk soil chromium | 28.15 µg/g; wet/dry basis unstated | Table 2 |
| Chromium added for the experiment | 176.7505 µg/g | Table 4 |
| Chromium assigned to removal | 91.3433 µg/g | Table 4 |
| Chromium remaining | 73.6055 µg/g | Table 4 |
| Recovered sum versus initial concentration | 164.9488 versus 204.9005 µg/g | Table 4 |
| Claimed removal | 44.58% after 24 h | Table 4 and equation |
| Electroosmotic flow | 3.13 mL/h | Conclusion |
Methods (brief)
Soil from one locality was characterized by X-ray diffraction and bulk elemental analysis, spiked with potassium dichromate, and treated at 15 V across a 10 cm soil compartment. Sulfuric-acid electrolytes were 0.05 M at the anode and 0.5 M at the cathode. The authors describe acid digestion followed by UV–visible measurement for Cr(VI); the article does not demonstrate oxidation-state preservation through this preparation.
Evidence fitness
The bulk soil measurements provide local environmental occurrence evidence. The electrical, electrolyte and mass-balance observations document a preliminary laboratory remediation trial. The reported percentage is a source calculation with unresolved mass and species accounting, rather than a validated field-remediation estimate.
Limitations
The experiment lacks replicated uncertainty and detection-limit reporting. Cadmium was reported as not detected without a numerical limit. Soil concentration basis is not identified as dry or wet. Background bulk chromium must not be substituted for Cr(VI). The plotted voltage endpoint also appears slightly below the minimum stated in the text. The printed issue establishes 2008; Crossref lists 2020 in its online-publication metadata and 2025 in its creation/deposit fields for the same article.
Related evidence
- Remediation evidence — drivers and interventions
- Soil-to-plant transfer of heavy metals
- Irrigation water and soil amendments as anthropogenic inputs to cropland
- Chromium
- Chromium, Hexavalent
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