Rubber from recycled car tyres is widely used as a soft, durable surface for playgrounds and sports fields but new research suggests that the material may be releasing toxic chemicals into the environment – and smaller particles pose the greatest risk.
A new study by researchers at Maria Curie-Skłodowska University in Poland has found that rubber granulate made from recycled tires contains alarmingly high levels of polycyclic aromatic hydrocarbons (PAHs), a class of persistent organic pollutants known to be toxic to humans and wildlife.
The team analysed three different particle sizes of rubber granulate, ranging from fine dust to larger chunks up to six millimeters across. They found that the smallest particles – those most likely to stick to skin or become airborne – contained more than twice the PAH concentration of the largest particles, with total PAH levels reaching as high as 108 milligrams per kilogram.
Crucially, the researchers did not stop at measuring total contamination. They also assessed the bioavailable fraction – the portion of PAHs that can actually leach out of the material and be taken up by living organisms – using a combination of chemical analysis and biological testing.
They found that fine rubber granulate proved toxic to every organism tested: it stunted root growth in plants, killed soil-dwelling springtails and reduced reproduction rates to zero at higher concentrations. Even water leached from the material harmed bioluminescent bacteria used in standard toxicity tests.
‘The smallest fraction contained the highest levels of total and freely dissolved PAHs and elevated potentially toxic elements, which translated into the strongest adverse effects’ the authors wrote. Larger particles, by contrast, showed lower contaminant levels and reduced toxicity.
Rubber granulate is commonly used in playgrounds, artificial turf fields and other public spaces where children spend hours in close contact with the material. Fine particles can adhere to skin, be inhaled, or migrate into surrounding soil and water.
While previous studies have highlighted the chemical complexity of tire-derived materials, this research is among the first to systematically link particle size to both chemical content and actual toxicity across multiple organisms. The authors argue that measuring total contamination alone is insufficient for risk assessment – what matters is what can leach out and cause harm.
The study concludes with the warning that finer rubber particles present a disproportionate environmental and potential health risk. The researchers call for stricter, size-aware regulations and urge consideration of safer alternatives for public spaces.
As the authors put it, rubber granulate is ‘not only a reservoir of PAHs but an active source of bioavailable contaminants’ – a reality that deserves closer attention from policymakers, manufacturers, and parents alike.
The full research can be read here.
Leave a Reply