The release of chemical additives from simulated abrasion tire wear particles: Insights from ICP-MS and GC-MS analysis

Abstract

Tire wear particles (TWPs), a major source of microplastic pollution, contain a complex mixture of chemical additives and are generated through the mechanical abrasion of tires. This study evaluates the physical characteristics and chemical toxicity of TWPs derived from four tires of varying mechanical strengths (T250, T350, T500, and T700). TWPs were produced in a controlled setting and characterized using microscopy, SEM, and FT-IR. While all samples shared a base composition of styrene-butadiene rubber, particle size and morphology differed with tire strength, with stronger tires generating larger, more irregular fragments. Leachate analyses using ICP-MS and GC-MS revealed the presence of both inorganic and organic contaminants. Zinc was the dominant metal, with concentrations reaching up to 4117 µg/L. GC-MS screening identified various organic compounds including benzothiazole, aniline, 6PPD, and BHT – known for their persistence and toxicity. Hazard classification based on GHS and UNEP criteria showed that many of the leached compounds are PBT or vPvB substances, posing significant ecological risks. The findings highlight that TWPs not only vary in physical form depending on tire strength but also release toxic additives capable of long-term environmental harm. This study emphasizes the importance of regulating chemical additives in tires and supports a more comprehensive approach to microplastic pollution assessment.