[Multimedia fate modeling with spatial resolution for phenanthrene in Tianjin]

Area of Science:

• Environmental Chemistry
• Multimedia Environmental Modeling

Background:

• Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) of environmental concern.
• Understanding phenanthrene's environmental fate is crucial for risk assessment.

Purpose of the Study:

• To model the behavior and fate of phenanthrene in Tianjin using a spatially resolved multimedia model.
• To identify the primary sinks and controlling factors for phenanthrene distribution in different environmental compartments.

Main Methods:

• A steady-state multimedia model was employed, incorporating spatial variations in soil organic carbon and fossil fuel emissions.
• The model divided soil and air into numerous sub-compartments, solving thousands of mass-balance equations simultaneously.
• Model validation was performed by comparing calculated concentrations and spatial distributions with observed data.

Main Results:

• Sediment was identified as the primary sink for phenanthrene, accumulating over 70% of the chemical.
• Phenanthrene's spatial distribution in surface soil is significantly influenced by soil organic matter content.
• Emissions from fossil fuel combustion were determined to be the dominant factor controlling phenanthrene distribution in ambient air.

Conclusions:

• The multimedia model accurately predicted phenanthrene concentrations and spatial patterns in Tianjin.
• Sediment plays a critical role in phenanthrene sequestration, highlighting the importance of aquatic environments.
• Environmental factors like soil organic matter and emission sources are key determinants of phenanthrene's fate and transport.