While tire wear and tear is known to be a major source of microplastics in the environment, its monitoring is still hampered by the lack of analytical methods able to provide concentrations in environmental matrices. Tire wear particles (TWP) present in road runoff enter the drainage system through gully pots, built to prevent sediment deposition in the drainage system, and eventually protect downstream receiving waters. The aim of this study was to detect and quantify TWP in gully pot sediments, by using a novel method combining Simultaneous Thermal Analysis (STA), Fourier Transform Infrared (FTIR) spectroscopy and Parallel Factor Analysis (PARAFAC). The method was applied to samples from five sites in Southern Norway, characterized by different traffic densities and patterns. The method involved no sample pretreatment, the whole sediment sample was submitted to thermal decomposition in STA, and gases generated during pyrolysis were continuously transferred to FTIR. The FTIR data were arranged in a trilinear multi-way dataset (samples × IR spectra wavenumber × pyrolysis temperature) and then analyzed by PARAFAC. The results showed that TWP concentrations in gully pots varied greatly across sites, ranging from below 1 mg TWP/g sediment in streets with the lowest traffic densities, to 150 mg TWP/g sediment at the most trafficked study site. The results also indicated that other traffic conditions, such as driving patterns influence TWP concentrations. Finally, by enabling quantification of TWP in gully pot sediments, the approach presented here supports environmental monitoring of TWP and safe disposal of gully pot sediments, which is critical for environmental pollution management.

Detection and quantification of tread wear particles in the environment have been a challenge owing to lack of a robust method. This study investigated the applicability of a combination of Simultaneous Thermal Analysis (STA), Fourier Transform Infra-Red (FTIR), and Parallel Factor Analysis (PARAFAC) in the detection and quantification of tire particles from formulated sediments. FTIR spectral data were obtained by heating 20 samples in STA. Among the 20 samples, 12 were tire granules in formulated sediments (TGIS) containing 1%, 2%, 5%, and 10% by mass of tire granules, while the remaining eight contained 0.5, 1, 2.5, and 5 mg of tire granules only (TGO). The PARAFAC models decomposed the trilinear data into three components. Tire rubber materials in tire granules (RM) and a combination of water and carbon dioxide were the components identified in all samples. The linear regression analysis of score values from the PARAFAC models showed that the RM quantity predicted were comparable to measured values in both TGIS and TGO. Decomposing the overlying components in the spectral data into different components, and predicting unknown quantity in both sample types, the method proves robust in identifying and quantifying tire particles from sediments.

Bioretention cells are popular stormwater management systems for controlling peak runoff and improving runoff water quality. A case study on a functional large-scale bioretention cell and a laboratory column experiment was conducted to evaluate the concentrations and retention efficiency of bioretention cells towards tire wear particles (TWP). The presence of TWP was observed in all soil fractions (500 µm) of the functional bioretention cell. TWP concentrations were higher (30.9 ± 4.1 mg/g) close to the inlet to the bioretention cell than 5 m away (19.8 ± 2.4 mg/g), demonstrating the influence of the bioretention cell design. The column experiment showed a high retention efficiency of TWP (99.6 ± 0.5%) in engineered soil consisting of sand, silty-sand, and garden waste compost. This study confirmed that bioretention cells built with engineered soil effectively retained TWP > 25 µm in size, demonstrating their potential as control measures along roads.

Motorsport is known for its high tire wear due to speed, cornering, and high acceleration/deceleration activities. However, studies on the generation of microplastics from racetracks are rare. This study aimed at quantifying microplastics concentrations in topsoil (0–5 cm) along a racetrack. The results showed that rubber materials (RM) and tire reinforcement microplastics (TRMP) were deposited in the soil along the racetrack. Concentrations of the two microplastics were affected by the distance from the edge of the racetrack (highest concentrations within 20 cm from the track) and track alignment (highest concentrations at the start/finish area). In addition, a weak correlation was observed between the concentrations of the two microplastics, suggesting the effect of track alignment on the type of microplastics abraded. The results also showed that coarser microplastics (1000–5000 μm) dominate the size distribution of microplastics along a racetrack. The findings of this study may provide racetrack managers with basic information for designing microplastic-controlling solutions. While additional studies are required to map environmental effects and policy measures, our initial results suggest that motorsport is of concern in terms of microplastics release to the environment.