Car tires wear down over time and need to be replaced. But where does all that worn material go?
Scientists say tiny microparticles from synthetic rubber tires often end up in waterways and inside aquatic animals. Eventually, those particles make their way into the stomachs of people who eat contaminated seafood.
A team of analytical chemists and ecologists from the University of Mississippi has confirmed that cars contribute more to environmental plastic pollution than any other source.
Microplastics: A Major Problem
Millions of tons of plastic waste enter the environment each year. Recently, researchers calculated that particles from tire wear account for about 45 percent of microplastics found in both terrestrial and aquatic systems.
As vehicles travel on roads, their tires shed tiny particles of rubber. Rain washes those wear particles into ditches, and from there they flow into streams, lakes, rivers, and oceans.
Fish, crabs, oysters, and other aquatic animals often ingest microplastics. Certain fish species, such as rainbow trout, brook trout, and coho salmon, have died because of toxic chemicals in tire wear particles.
In 2020, researchers discovered that more than half of the coho salmon returning to spawn in Washington State streams had died primarily due to 6PPD-Q—a chemical added to tires.
These particles threaten not only aquatic life but also humans and terrestrial animals, especially those living near major highways. Microplastics from tires pollute waterways and the air, as reported by ScienceAlert.
In a study conducted in China, the chemical 6PPD-Q was found in the urine of both children and adults and has been linked to serious harm to the liver, lungs, and kidneys.
How Can We Reduce the Impact of Tire Wear Particles on the Environment?
Searching for low-impact ways to remove these particles from waterways, the university team developed a technology based on readily available, inexpensive natural materials.
The idea is simple: capture tire wear particles before they reach streams, rivers, and oceans.
The team tested biofilters made from pine bark and biochar (charcoal produced by heating rice husks in a low-oxygen chamber). They found these filters could remove about 90 percent of tire wear particles from wastewater.
The biofiltration system was installed at the entrance to a drainage outlet. Researchers collected samples of stormwater runoff and measured the concentration of tire wear particles before and after the system was installed. After the biofilter was in place, the concentration of microplastic particles decreased significantly.
Because biochar and wood chips can be sourced from agricultural waste, they are relatively inexpensive and accessible to local communities.
To determine the method’s effectiveness and scalability, researchers need long-term monitoring studies, especially in areas with heavy vehicle traffic.
The source of the filter materials also matters. There are concerns that untreated agricultural waste may release organic pollutants.
Like most filters, biofilters need to be replaced over time, and used filters must be disposed of properly because they accumulate harmful particles.
Plastic waste harms the environment, the food we eat, and our health. The team believes that biofilters made from plant waste could be an effective, relatively inexpensive, and environmentally friendly solution.
Photo: pixabay.com
