Longitudinal and Vertical Distribution Pattern of Tire Wear Particles in an Urban Bioswale
Résumé
Tire wear particles (TWPs) are generated by the abrasion of tire tread in contact with the road surface. These particles, continually emitted by road traffic, have been found to permanently permeate ecosystems- making TWPs a major source of microplastics in the environment. TWPs contain various chemicals and additives which represent a proven risk for receiving environments impacted by runoff from road surfaces. Presently, bioswales- a type of Sustainable Urban Drainage System (SUDS) - constitute crucial infrastructure for managing runoff water by reducing the pollutant load in the environment. The study focuses on a bioswale located beside a one-way road in the Bottière-Chênaie eco-district (Nantes, France). The objective of the study is to quantify and characterize the longitudinal and vertical distribution of TWPs in the bioswale. Soil samples for this study were collected from the surface and at different depths in the bioswale. The samples were analyzed by pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC-MS) targeting traditional synthetic and natural rubbers constituting vehicle tires. The first results indicate high and homogeneous levels of TWP contamination for the soil near the one-way road. The results also confirmed that TWPs accumulate near input zones. These results imply that regularly replacing the top soil near identified input zones can likely be sufficient to restore its original infiltration capacity and quality. In the future, we will analyze the soil samples from the vertical profiles to further confirm the locations of TWP accumulation in the bioswale. This work contributes scientific knowledge on the extent and distribution of TWP contamination in a common type of green infrastructure, i.e., bioswale. It aims to contribute towards improvement of the knowledge base of the fate of TWPs in bioswales and establishment of effective strategies for managing such infiltration-based systems.