Microplastics in road dust: A practical guide for identification and characterisation

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Microplastics (MPs) in road dust are a global environmental and health issue, primarily from plastic litter and tire wear.
• Current detection methods (Raman, FTIR, SEM) are limited for analyzing MP shape and particles smaller than 20 μm, necessitating faster, cheaper techniques.
• Incorporation of recycled plastics in infrastructure highlights the need for advanced MP analysis in road dust.

Purpose of the Study:

• To investigate Nile red (NR) fluorescence microscopy for detecting microplastics in road dust.
• To optimize NR staining parameters (duration, temperature, solvent, concentration) for road dust analysis.
• To assess the method's capability in determining MP amount, shape, and size distribution.

Main Methods:

• Optimization of Nile red staining procedure using 33 road dust samples and 13 plastic types.
• Application of NR fluorescence microscopy for microplastic detection and characterization.
• Evaluation of MP differentiation from non-plastic road dust materials down to 1 μm.

Main Results:

• Developed an optimized NR staining protocol for microplastic detection in road dust.
• Successfully differentiated microplastics from non-plastic materials down to 1 μm.
• The method provides information on MP amount, shape, and size distribution.

Conclusions:

• Nile red fluorescence microscopy offers a promising, accurate, and cost-effective approach for microplastic analysis in road dust.
• This technique can be applied to assess MP pollution from plastic-modified roads and compare urban/rural pollution levels.
• Enables rapid, simple, and reliable monitoring of microplastics in road dust for future research.