Thibault Masset

Tire and road wear particles (TRWP) are produced during abrasion of tires on road pavement. Low amounts of small-sized TRWP (10 m) enter the atmosphere during use but between 95 99% of total emitted TRWP are expected to be deposited on the road side and be transferred into the nearby soil, from which a fraction will eventually enter surface water. A modelling study estimated that 49% of TRWP emitted on the road would reach the freshwater system in the French Seine basin. Field measurements suggest that levels of TRWP decrease between its emission source and the aquatic environment with concentrations of 0.1 – 100 g kg-1 on the road side, 0.5 1.2 g kg-1 in river sediment and 0.5 5 mg L-1 in river water. Chemicals such as 2-mercaptobenzothiazole (MBT) and 1,3-diphenylguanidine (DPG) are intensively used as vulcanization agents; they can represent up to 0.5 % of the tire rubber. Phenylenediamine compounds, such as N-(1,3-dimethylbutyl)-N-phenyl-1,4-phenylenediamine (6PPD), are also commonly used as antioxidants and antiozonants (about 0.9% of the tire tread). The distribution and fate of TWPs and associated chemicals in the aquatic environment is still poorly understood. Moreover, the potential toxic impacts of these tire-associated chemicals for aquatic biota vary widely suggesting specific species sensitivity.