Decoding microplastic pollution in China freshwater: interpretable machine learning insights into...

Area of Science:

• Environmental Science
• Ecotoxicology
• Polymer Science

Background:

• Microplastic (MP) pollution and phthalate ester (PAE) leaching threaten freshwater ecosystems.
• China, a major plastic producer, lacks detailed MP distribution and PAE risk data.

Purpose of the Study:

• To map the national distribution of five dominant MPs in China.
• To assess the ecological risks of PAE leaching from MPs.
• To develop a transferable framework for pollution management.

Main Methods:

• Compiled data from 846 river and lake sites (2014-2024).
• Developed an interpretable multi-output multilayer perceptron (MLP) model for MP distribution mapping.
• Conducted national risk assessment of PAE leaching, focusing on DEHP.

Main Results:

• Precipitation linked to PVC/PET in rivers; temperature to PE/PP in lakes.
• Di(2-ethylhexyl) phthalate (DEHP) identified as the primary PAE concern.
• Ecological risks ranged from low to medium, varying by leaching scenario and region.

Conclusions:

• Provides the first national-scale quantification of MP distribution and PAE leaching risks in China.
• Highlights the importance of composition-specific analysis for accurate risk assessment.
• Offers a robust framework for targeted environmental management and policy development.