Multi-Type Microplastic Migration Model Driven by River Hydrodynamic Conditions

Area of Science:

• Environmental Science
• Fluid Dynamics
• Chemical Engineering

Background:

• Predicting microplastic migration in aquatic environments is challenging.
• Existing models lack the ability to account for diverse microplastic characteristics.

Purpose of the Study:

• Develop a hydrodynamically driven migration model for various microplastics.
• Improve the accuracy of microplastic transport prediction in freshwater systems.

Main Methods:

• Conducted hydraulic experiments to establish hydrodynamic thresholds for microplastic movement.
• Integrated hydrodynamic forces, gravity, buoyancy, and interparticle interactions into the model.
• Incorporated microplastic size, shape, and material properties for differentiated prediction.

Main Results:

• The model accurately simulated microplastic migration and pollutant accumulation in the Mulanxi River basin.
• Microplastics <0.5 mm (71.62%) dominated, primarily fragmentary and fibrous types.
• Material density and physicochemical properties significantly influenced migration behavior; transport rates correlated with pollution sources and lightweight microplastics.

Conclusions:

• The developed model offers enhanced mechanistic understanding and predictive capability for microplastic transport.
• Provides theoretical and methodological support for freshwater pollution control.
• Demonstrated reliability and applicability through consistency with observational data.