A two-part study published in 2018 (part 1, part 2) focused on the Seine watershed (France) and concluded that most TRWP is deposited on roadside soil, whilst around 18% of TRWP can be removed from the road surface as runoff and reach surface waters.
In the case of the Seine watershed, it is expected that more than 60% of the TRWP that reaches surface waters is transported to wastewater treatment. The study suggests that 2-5% of TRWP is expected to travel as far as the estuary.
Early TIP-sponsored studies (1, 2, 3) into the potential presence and acute and chronic toxicity of TRWP in freshwater environments suggested that TRWP present low toxicity and low risk to freshwater- and sediment-dwelling species.
However, we acknowledge that there is much to learn about the particles generated through the normal use of tires and our studies into the potential environmental impacts of TRWP continue with work that includes investigation into the impact on organisms of long-term exposure to TRWP.