Plastic fibers shed from synthetic textiles caused the most damage to crop plants in a new study that tested microplastics and nanoplastics under conditions designed to mirror real agricultural settings. The research, led by Griffith University's Dr. Shima Ziajahromi, was published in the journal Environmental Science and Pollution Research.
Using wheat and tomato plants grown in contaminated soil, the team found that microplastics reduced both plant growth and chlorophyll content. PET fibers, the kind that break off from synthetic fabrics, produced the most harmful effects, particularly in tomatoes. Mixtures of micro- and nanoplastics were more toxic than single particle types, suggesting the two work together to amplify damage.
The nanoplastics went further. They were taken up into plant tissue and moved inside the plant itself, appearing in roots, stems, and even leaf tissue in tomatoes. That finding is significant because it means plastics entering the soil do not simply stay there.
"Agricultural soil is not just a sink for plastics, but a pathway into the food systems, meaning they could end up on our plates," Ziajahromi said.
Unlike much of the earlier laboratory research on this topic, the Griffith study used aged plastics, realistic particle concentrations, and polymer types actually found in biosolids and farm soils. The team also found that plants trap larger microplastic particles in their root systems, which may slow how far those particles spread through the environment. But it also means plastics accumulate around the roots themselves.
Ziajahromi called for new regulatory frameworks based on real-world plastic exposure data, as well as targeted strategies to reduce plastic inputs into agricultural land.
