The impact of car travel on the environment is well known. Exhaust emissions pollute the atmosphere with gases that raise global temperatures and make the air less safe to breathe. Sadly, the problems don’t end there. Scientists have been studying another problem – and one that connects your daily commute to the most remote stretches of the world’s oceans.
A new study has revealed that microplastics released from car tires and brake systems are a major source of marine plastic pollution – much more than previously thought. Every year, 100,000 metric tonnes of microplastics are shed from tires, transported through the air and dumped in the ocean. Another 40,000 tonnes comes from brakes. To put that in perspective, if the average scrapped car tire is around nine kilograms, then the total weight of microplastics reaching the sea each year equates to just under 11 million tires.
Microplastics are polymers smaller than 5mm, and they are hazardous to the health of animals that are exposed to them. The different shapes and densities of microplastics cause them to disperse throughout habitats, making them available for different species to eat. In the ocean, microplastics can accumulate in an animal’s gills or digestive tract. Laboratory studies on fish and molluscs have shown that this can affect respiration, feeding and growth.