Column washing of Bangalore-area industrial sludge removed substantially more metals with hydrochloric acid plus EDTA than with distilled water. This is a remediation experiment relevant to sludge contamination pathways, with no measurements in food or a demonstrated safe land-application endpoint.
Key numbers
Figure 4 labels provide greater precision: Cu 93.74%, Zn 98.44%, Fe 79.32%, nickel (Ni) 88.74%, cadmium (Cd) 94.17%, lead (Pb) 82.84%, chromium (Cr) 71.17%. These coexist with the rounded prose values above.
The initial sludge mg/kg reporting basis is not stated in the source.
Methods (brief)
Sludge collected November 2013 and analyzed using USEPA 3050 B. Air-dried, 2 mm-sieved material compacted to 0.98 g/cm³ and 33.5% water content; pore volume 56.55 cm³. Columns compared distilled water against 0.1 N HCl+0.1 N EDTA. Transport parameters fitted to experimental elution curves. Sampling and analytical-replicate counts and numeric detection limits are not provided.
Implications
Supports laboratory washing and contaminant-transport comparisons. Metal-rich leachate still requires management; the study does not establish agricultural reuse or field-scale safety.
Evidence Fitness: EF-2 for source-reported removal and transport estimates; environmental remediation context, with replication and reporting-basis gaps.
Related evidence
- Remediation evidence — drivers and interventions
- Irrigation water and soil amendments as anthropogenic inputs to cropland
- Copper
- Zinc
- Iron
- Chromium
- Cadmium
- Nickel
- Lead
Update history
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