Scientists call for urgent action as toxic compounds from tyre wear threaten microscopic ocean life and the health of coastal marine food webs
Chemicals released from car tyres as they wear down are washing into rivers, estuaries and the sea and they could be disrupting life at the base of the marine food web, according to a new study.
Researchers from the University of Portsmouth found that just four days of exposure to three common tyre-derived chemicals significantly slowed the growth of tiny marine algae known as diatoms - single-celled plants that produce oxygen and support entire ocean ecosystems.
The study focused on a species called Phaeodactylum tricornutum, a diatom that like others, is responsible for converting sunlight and carbon dioxide into energy that is used by animals - a process that helps sustain fish, crustaceans and other marine life.
The findings raise concerns about how urban road runoff could be impacting the oceans, especially in densely populated areas where concentrations of tyre chemicals are already high.
The research team examined three chemicals that are widely used in tyre manufacturing or formed as byproducts as tyres degrade: mercaptobenzothiazole (MBT), diphenylguanidine (DPG), and 6PPD-quinone. All three are known to enter the environment via stormwater and urban runoff, but until now, their specific effects on marine plant life have been poorly understood.
The results showed all three chemicals suppressed diatom growth, with DPG and MBT proving especially harmful even at very low concentrations, levels already recorded in waterways in countries including Canada, China and Australia. 6PPD-quinone, which has previously been implicated in mass die-offs of coho salmon, was less acutely toxic to diatoms but still raised concerns. It required higher concentrations to cause damage, but because it’s widespread and persistent, the researchers warned it could accumulate in marine environments over time.
Posted On: 04/08/2025
More on: