Might look healthy. But researchers from Vienna have detected toxic substances in lettuce.
Microplastics have long since made their way into our food. For example, if fish eat the small particles, they end up on our plates. Scientists led by environmental scientist Thilo Hofmann from the Center for Microbiology and Environmental Systems Science at the University of Vienna have now also detected toxic substances from the abrasion of car tires in lettuce.
Wind, sewage sludge and waste water carry the tire particles to the fields, where the pollutants they contain can get into the vegetables.
In their study, which was published in the journal “Environmental Science & Technology”, the researchers conducted several experiments to investigate whether edible plants absorb the pollutants. To do this, they added five chemicals used in tire production to the nutrient solutions of lettuce plants in the laboratory.
“Unpredictable health hazard”
“Our measurements showed that the lettuce plants took up all the compounds we examined via the roots, transferred them to the lettuce leaves and accumulated there,” says Anya Sherman from Hofmann’s team. This uptake also occurred when the lettuce plants were not directly exposed to the chemicals, but rather indirectly via tire granules in the root region.
The researchers also identified those substances that were formed from the chemicals absorbed during the plant’s metabolism. These metabolites are compounds that have not yet been described, whose toxicity is unknown and which therefore “pose an unpredictable health risk,” emphasized Thorsten Hüffer from Hofmann’s team.
Car tires are a significant source of microplastics that pollute the environment. As they write in a statement, about one kilogram of tire particles per inhabitant and year is blown into the environment with the wind and washed into rivers and sewage by rain. According to the study, the extent of tire particle emissions is still poorly quantified. (SDA/hei)