Method Development for Separation and Analysis of Tire and Road Wear Particles from Roadside Soil Samples

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Standardized methods for detecting tire and road wear particles (TRWPs) in soils are lacking.
• Existing technological inconsistencies hinder accurate TRWP quantification in terrestrial environments.

Purpose of the Study:

• To develop and validate a simple, cost-effective, and widely applicable protocol for TRWP detection and quantification in soils.
• To advance TRWP research in terrestrial ecosystems.

Main Methods:

• Developed a protocol involving soil sampling, size and density separation, and organic matter removal using hydrogen peroxide.
• Analyzed roadside soil samples from Kansas and Ohio, USA.
• Utilized infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) for particles >1 mm.
• Employed Soxhlet extraction followed by gas chromatography-mass spectrometry (GC-MS) for particles <1 mm.

Main Results:

• SEM-EDX confirmed tire-related elemental combinations (S + Zn/Na) ± (Al, Ca, Mg, K, Si).
• GC-MS identified probable tire-related intermediates including ketones, carboxylic acids, epoxies, cyclohexane, and benzothiazole sulfenamide (BTS).
• The protocol demonstrated effectiveness in identifying TRWPs and their associated chemical markers in soil samples.

Conclusions:

• The presented protocol is simple, widely applicable, and cost-effective for TRWP analysis in terrestrial environments.
• This method can significantly assist in advancing research on TRWPs and their environmental impact.