Evaluating potential non-point source loading of PAHs from contaminated soils: a fugacity-based modeling approach

Area of Science:

• Environmental Chemistry
• Soil Science
• Environmental Modeling

Background:

• Soils contaminated with Polycyclic Aromatic Hydrocarbons (PAHs) face significant non-point source (NPS) pollution during rainfall.
• The traditional enrichment ratio (ER) method may be inadequate for assessing PAH contamination.
• Understanding PAH transport dynamics is crucial for effective environmental management.

Purpose of the Study:

• To develop and validate a novel model for estimating the enrichment ratio (ER) of PAHs.
• To investigate the influence of sediment composition and its evolution on PAH transport.
• To propose a strategy for evaluating NPS loading of PAHs in heterogeneous watersheds.

Main Methods:

• Development of a new ER model incorporating the fugacity concept.
• Validation of the model using experimental data.
• Systematic examination of modeling uncertainty, focusing on compound dependency.

Main Results:

• The developed ER model accurately estimates PAH transport, considering physicochemical properties and dynamic sediment composition.
• Modeling uncertainty is significantly dependent on the specific PAH compound.
• The study provides a practical strategy for assessing NPS PAH loading in complex watershed environments.

Conclusions:

• The fugacity-based ER model offers a more accurate approach for PAH pollution assessment.
• Sediment characteristics play a critical role in PAH transport during rainfall events.
• The findings are vital for improving watershed-scale modeling and management of NPS pollution from PAHs and similar contaminants.