Lettuce plants take up chemicals that are released by tyre abrasion: The picture shows the actual experimental setup in which the researchers added tyre abrasion to the nutrient solutions of lettuce plants. Credit: Gabriel Sigmund
Key Points:
- A new study shows pollutants contained in tire particles blown from the road to the farm can harm crops.
- Lettuce plants were found to uptake all of the compounds studied, some which are considered highly toxic.
- Further investigations are needed to learn how this process actually takes place in arable soils.
A new study by researchers at the University of Vienna showed that growing lettuce absorbs toxic pollutants contained in the particles from tires, which are carried from roads to farmland.
Driving a car produces tire wear particles, which are blown into the environment by the wind and washed into rivers and sewage by the rain. But, tire wear particles and other types of microplastics contain additives that can release pollutants into the soil or water.
In the current study, published in Environmental Science & Technology, the researchers wanted to shed light on whether the pollutants could migrate from soil into crops.
The team used high resolution mass spectrometry to not only measure the extent to which chemicals ended up in the lettuce plants, but also identify the substances to which the lettuce plants metabolized the chemicals.
"The plants processed the substances and in doing so they produced compounds that have not been described before. Since we don't know the toxicity of these metabolites, they pose a health risk that cannot be assessed so far," said Thorsten Hüffer, senior scientist at the Centre for Microbiology and Environmental Systems Science (CMESS).
The metabolites identified by the team are stable in the plant, meaning they would likely be preserved until reaching our plates.
However, the researchers say such compounds can be easily broken down by the human body.
"If someone eats such a contaminated lettuce, the original chemicals could be released again in the body," said co-first author Anya Sherman, Ph.D. student at CMESS.
The researchers hypothesize that the uptake process occurs differently in soil systems. Therefore, next, they are looking at the possible uptake of tire additives by plant roots in natural soils.
Additionally, study co-author Ruoting Peng is part of a team working on an ongoing project to obtain data on the concentration of chemicals along the Danube River.