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Updated: May 25, 2026
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Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation
Published on: July 4, 2014
Activated carbon amendment to sequester PAHs in contaminated soil: a lysimeter field trial
Sarah E Hale1, Marie Elmquist, Rahel Brändli
1Department of Environmental Engineering, Norwegian Geotechnical Institute, Ullevål Stadion, N-0806 Oslo, Norway.
Chemosphere
|January 24, 2012
Summary
Activated carbon (AC) soil amendment effectively reduced polycyclic aromatic hydrocarbon (PAH) concentrations. Granular AC showed higher reductions in drainage water, while powder AC excelled at lowering free PAH in soil pore water.
Area of Science:
- Environmental Science
- Soil Science
- Remediation Technologies
Background:
- Soil contamination by polycyclic aromatic hydrocarbons (PAHs) poses environmental risks.
- In situ remediation using activated carbon (AC) is an emerging strategy.
- Field-scale application of AC for PAH-contaminated soil requires efficacy assessment.
Purpose of the Study:
- To evaluate the effectiveness of powder activated carbon (PAC) and granular activated carbon (GAC) for in situ remediation of PAH-contaminated soil.
- To compare the performance of PAC and GAC in reducing total and free aqueous PAH concentrations.
- To assess secondary effects of AC amendment on dissolved organic carbon and nutrient levels.
Main Methods:
- Field-scale amendment of PAH-contaminated soil with 2% PAC and GAC.
- Monitoring PAH concentrations in drainage water using direct solvent extraction and polyoxymethylene (POM) passive samplers.
- Measuring free aqueous PAH concentrations in soil pore water with POM samplers.
- Analyzing dissolved organic carbon (DOC) and nutrient concentrations (nitrate, nitrite, ammonium, phosphate, total phosphorus, potassium, calcium, magnesium).
Main Results:
- GAC reduced total PAH in drainage water by 59%, while PAC reduced it by 14% after 12 months.
- POM samplers indicated a 93% reduction for PAC and 56% for GAC in drainage water PAH.
- Free aqueous PAH concentrations in soil pore water decreased by 93% (PAC) and 76% (GAC) after 17-28 months.
- PAC was more effective than GAC in reducing free PAH concentrations compared to total dissolved PAH.
- AC amendment led to DOC binding and variable nutrient concentration changes.
Conclusions:
- Both PAC and GAC are effective in reducing PAH contamination in soil, with differing impacts on total versus free concentrations.
- PAC's potential leaching of fine particles may explain its higher efficacy in reducing free PAH in pore water.
- AC amendment can influence soil chemistry by immobilizing DOC, but nutrient dynamics are complex and influenced by environmental factors.
