Refining the aquatic microplastic risk assessment framework through dynamic flux simulation and ecological...

Area of Science:

• Environmental Science
• Ecotoxicology
• Hydrology

Background:

• Existing models struggle with river cross-section dynamics and spatial variations in species sensitivity.
• Traditional ecological risk assessments often use uniform thresholds, ignoring local biodiversity.

Purpose of the Study:

• To develop a microplastic flux simulation (MFS) model for dynamic riverine microplastic transport.
• To create a species sensitivity distribution-based ecological risk assessment (SSD-ERA) method accounting for spatial heterogeneity.
• To apply these models to the Jinsha River for assessing microplastic pollution risks.

Main Methods:

• Coupling hydrological processes with microplastic emission and transport mechanisms in the MFS model.
• Dynamically adjusting ecological risk thresholds based on local aquatic species richness in the SSD-ERA method.
• Validating model performance using observed data from the Jinsha River.

Main Results:

• The MFS model demonstrated strong predictive performance in simulating microplastic dynamics.
• Surface-layer microplastic flux in the Jinsha River ranged from 0.66 to 276.82 tons/yr.
• 13.04-43.47% of the watershed was identified as medium-to-high risk for aquatic life.

Conclusions:

• The study provides a refined methodological framework for aquatic microplastic flux and risk modeling.
• Spatial threshold adjustment is critical for accurate ecological risk assessment in riverine environments.
• The developed models offer improved tools for managing microplastic pollution in aquatic ecosystems.