Aqueous solubility calculation for petroleum mixtures in soil using comprehensive two-dimensional gas chromatography
Debin Mao1, Richard Lookman, Hendrik Van De Weghe
1Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium.
Journal of Chromatography. A
|September 9, 2008
Summary
This study introduces a new method to accurately calculate petroleum hydrocarbon (TPH) leaching potential in soil. It uses advanced chromatography to determine TPH equilibrium concentrations in groundwater, improving risk assessment and remediation strategies.
Area of Science:
- Environmental Chemistry
- Analytical Chemistry
- Geochemistry
Background:
- Assessing aqueous solubility of petroleum hydrocarbons (TPH) in soil is crucial for evaluating migration risks and guiding soil/groundwater remediation efforts.
- Field monitoring wells can overestimate TPH concentrations due to the presence of pure oil, necessitating more accurate assessment methods.
- Understanding the leaching potential of TPH is vital for effective environmental protection and site cleanup.
Purpose of the Study:
- To develop and validate a method for calculating TPH equilibrium concentrations in groundwater based on soil analysis.
- To provide a more accurate assessment of TPH leaching potential compared to traditional field measurements.
- To enhance the evaluation of migration risks and inform soil and groundwater remediation strategies.
Main Methods:
- Soil samples were analyzed using high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography (HPLC-GCxGC).
- TPH in soil was fractionated into 79 defined hydrocarbon groups, each assigned a representative water solubility.
- Raoult's law was applied to calculate the overall equilibrium water solubility of non-aqueous phase liquid (NAPL) and the water phase composition.
Main Results:
- The HPLC-GCxGC method successfully divided TPH into 79 distinct hydrocarbon fractions.
- Calculated equilibrium water solubilities and TPH compositions closely matched measurements from column recirculation experiments.
- The method demonstrated good agreement with both spiked soil samples and a field-contaminated soil.
Conclusions:
- The developed calculation method accurately predicts TPH equilibrium concentrations in groundwater from soil analysis.
- This approach offers a reliable alternative to potentially overestimated field measurements for assessing TPH leaching potential.
- The findings support improved risk assessment and more effective soil and groundwater remediation planning.
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