Transfer of tire-related additives and their metabolites into vegetables and assessment of human exposure through food

• Research unit: FSVO
• Project number: 4.23.08

Key words (German)

Reifenabrieb, Exposition

Short description (English)

The extent of ongoing emissions of tire wear particles (TWP) into the environment remains poorly quantified, however global emissions are estimated at 6 million tons per year.1 Tire wear particles are introduced into agricultural soils by several routes, including atmospheric deposition and road run-off.2 Tire particles contain a number of chemical substances whose human toxicity is still unknown. Recent studies on aquatic animal species have shown that some of these additives or their metabolites are toxic. For instance, 6-PPD-Q which is a transformation product of the antioxidant 6-PPD is neurotoxic for some fish species.  These substances are released into the environment and can be assimilated by living organisms such as invertebrates, fish and plants. Recently, Castan et al have shown through laboratory experiments that tire-related additives can be assimilated and accumulated by lettuces.2 More recently, the consumer magazine K-Tipp also conducted a study to assess the presence of these additives in salads sold on the Swiss market. The results published on August 23rd 2023 showed that 12 out of 15 samples analyzed for this study contained significant concentrations of these substances. These results suggest that there is a risk of these substances being transferred into the food chain, particularly through the consumption of vegetables.