Every year, billions of vehicles worldwide shed an estimated 6 million tonnes of tire fragments.

These tiny flakes of plastic, generated by the wear and tear of normal driving, eventually accumulate in the soil, in rivers and lakes, and even in our food. Researchers in South China recently found tire-derived chemicals in most human urine samples

We urgently need to classify tire particles as a unique pollution category. In our recent international study, colleagues and I found that this approach would drive more focused research that could inform policies specifically designed to mitigate tire pollution.

Right now, delegates are meeting in South Korea to negotiate the first global plastics pollution treaty. While this landmark agreement is poised to address many aspects of plastic pollution, tire particles are barely on the agenda.

Given their significant contribution to microplastics, recognizing tire pollution as a unique issue could help unlock targeted solutions and public awareness. This is what we need to address this growing environmental threat.

Hundreds of chemical additives

Tire particles tend to be made from a complex mix of synthetic and natural rubbers, along with hundreds of chemical additives. This means the consequences of tire pollution can be unexpected and far reaching.

For instance, zinc oxide accounts for around 0.7 percent of a tire’s weight. Though it is essential for making tires more durable, zinc oxide is highly toxic for fish and other aquatic life and disrupts ecosystems even in trace amounts.

Another harmful additive is a chemical known as 6PPD, which protects tires from cracking. When exposed to air and water, it transforms into 6PPD-quinone, a compound linked to mass fish die-offs in the US.

A Whopping 30 Percent of Microplastics Come From This Unexpected Source
Coho salmon seem to be particularly affected by car tire chemicals. (BLM Oregon / flickr)

To assess their full ecological impact, we need more detailed information on which tire additives are most toxic, how they behave in the environment, and which species are most at risk (some salmon species are more sensitive to 6PPD-quinone than others, for example).

With more than 2 billion tires produced each year to fit ever-heavier and more numerous cars, the problem is set to escalate. The environmental toll will only increase unless we recognize and target the specific problem.

Measures like weight-based taxation and eco-friendly tire innovations would not only reduce tire pollution but also pave the way for more sustainable transportation systems. The question isn’t whether we can afford to act. It’s whether we can afford not to.The Conversation

Henry Obanya, PhD Candidate, Ecotoxicology, University of Portsmouth

This article is republished from The Conversation under a Creative Commons license. Read the original article.