Spatial variability in compartmental fate modelling : Linking fugacity models and GIS

Area of Science:

• Environmental chemistry
• Environmental modeling
• Chemical fate and transport

Background:

• Compartmental mass balance models often simplify environmental heterogeneity.
• Existing fugacity models assume uniform conditions within compartments.
• Accurate chemical fate assessment requires accounting for spatial environmental variations.

Purpose of the Study:

• To develop a novel approach for compartmental mass balance models that addresses spatial environmental heterogeneity.
• To integrate sub-unit specific environmental parameters into chemical fate modeling.
• To enhance the linkage between fugacity models and geographical information systems.

Main Methods:

• The approach assumes chemical equilibrium within a phase despite environmental heterogeneity.
• Composite D- and Z-values are derived from sub-unit specific parameters.
• Mass balance equations are solved using these composite values, yielding a common fugacity per compartment.

Main Results:

• Sub-unit specific concentrations and process rates can be calculated from the common fugacity value.
• The method was illustrated using the QWASI lake model for hexachlorobenzene fate.
• The approach allows for numerous sub-units per compartment without significant complexity increase.

Conclusions:

• The new method effectively incorporates spatial heterogeneity into chemical fate models.
• It enables detailed analysis of chemical behavior in environmentally diverse compartments.
• This approach is crucial for connecting fugacity models with geographical information systems for advanced environmental assessment.