Adapting Methods for Isolation and Enumeration of Microplastics to Quantify Tire Road Wear Particles with...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Tire road wear particles (TRWPs) have a complex composition and density range, challenging their isolation and identification in environmental matrices.
• Accurate quantification of TRWPs is crucial for assessing their environmental fate and ecological effects.

Purpose of the Study:

• To adapt and validate methods for single-particle enumeration of TRWPs from environmental samples.
• To establish reliable isolation and identification techniques for TRWPs, addressing challenges posed by their varied composition and density.

Main Methods:

• Employed a two-stage density separation using saturated NaCl and sodium polytungstate for TRWP isolation from sediments.
• Investigated the compatibility of tire microrubber with various digestion reagents (NaOH, KOH, H2O2, NaOCl).
• Utilized elasticity and heat resistance for differentiating TRWPs from bitumen particulates, with SEM and Py-GC-MS for confirmation.

Main Results:

• Alkaline digestions (NaOH, KOH) were found compatible with tire microrubbers.
• Oxidative reagents (H2O2, NaOCl) negatively impacted TRWP elasticity and integrity.
• The adapted method successfully enumerated TRWPs in road dust samples, with qualitative confirmation via SEM and Py-GC-MS.

Conclusions:

• The developed method provides a robust approach for TRWP isolation and identification in environmental monitoring.
• Understanding TRWP characteristics, including shape diversity (aspect ratio data provided), is essential for environmental risk assessment.
• The study highlights the importance of selecting appropriate digestion reagents to preserve TRWP properties.