Microplastics from tires: New study highlights devastating consequences for the Rhine

Microplastics from tires: New study highlights devastating consequences for the Rhine

A new study by researchers at University of Duisburg-Essen and the University of Cologne reveals alarming effects of microplastics on the microbial world in the Rhine. The research, published in the specialist magazineEnvironmental Pollution, investigates the influence of tire wear, a significant cause of microplastics, on aquatic ecosystems. Over a period of four weeks, different types of tire particles were exposed to the flow in the river.

The results show that tire particles significantly influence the composition of biofilms that coat river rocks, sediments and man-made materials. Certain types of bacteria tend to preferentially colonize tire wear, while the overall diversity of microorganisms decreases. These changes in the biofilms not only have a local effect, but also influence the entire river system. It is noteworthy that biofilms on older tire particles differ significantly from natural particles on the river bottom.

The sources of microplastics

According to that ADAC In Germany, around a third of all microplastic emissions come from abrasion from car tires. Around 500,000 tonnes of tire wear are generated in the EU every year. These particles end up in water and soil. However, the majority often remains on the road, where it is caused by the transmission of force between the tires, the road and the dirt. The properties of the tire wear particles produced, which are referred to as “TRWP” (tire and road wear particles), are a mixture of different substances.

Just last week, lawmakers discussed future tire wear limits. These will apply to passenger car tires from July 1, 2028. The UNECE proposal provides for a limit on tire wear per tonne of vehicle weight. Evidence suggests that a limit that is too strict could compromise driving safety, as a linear relationship between vehicle weight and tire wear has been demonstrated. Factors that increase wear include mountainous regions, wet roads and high speeds.

Ecological impacts and necessary measures

Scientists have found that tire wear accumulates not only in water, but also in soil. As a study by FiBL and the University of Darmstadt shows, around one kilogram of microplastics per person are produced in Switzerland every year from tire wear. This gets into the ground via rain, wind and splash water. Worrying amounts of microplastics can be detected, especially along country roads with little traffic.

The study also highlights the need for measures to reduce exposure. Optimized road surfaces, innovative tire formulations and efficient drainage systems are urgently needed to protect the environment and the health of microbial communities in water and soil. These findings come from a project financed by the Federal Office of Agriculture (BLW) and benefit from funds from the EU project MINAGRIS, which deals with agricultural sources of microplastics.

The results of this research are important not only for the Rhine, but also for other bodies of water. They complement the findings of the North Rhine-Westphalia State Office for Nature, Environment and Climate (LANUK), which has already identified high levels of primary microplastics in the Rhine. These findings are an important contribution to a better understanding of the ecological consequences of microplastics and should be incorporated into future political debates.