TU Darmstadt demonstrates storage of microplastics in forests for the first time
Micro- and nanoplastics pollute not only oceans, rivers, and agricultural soils, but also forests. This is shown by a recent study by geoscientists at TU Darmstadt , published Nature Communications Earth & Environment
According to the study, the tiny plastic particles primarily enter the forests from the air and accumulate in the soil. "The microplastics from the atmosphere initially settle on the leaves of the treetops; scientists refer to this as the so-called combing-out effect," explains lead author Dr. Collin J. Weber from the Institute of Applied Geosciences at TU Darmstadt. Rain or autumnal leaf fall then transport the particles to the forest floor.
Microplastics stored deep in the soil
The study shows that while the highest concentrations of microplastics are found in the upper layers of leaf litter, large amounts are also stored in deeper soil layers. This is due to both the decomposition of the leaves and transport processes by the organisms involved.
For their study, the researchers took samples from four forest sites east of Darmstadt. Using a newly developed analytical method, they were able to detect and chemically identify microplastics in soil samples, leaf litter, and atmospheric deposits. They also created a model calculation that estimates inputs since the 1950s.
Forests as indicators of air pollution
"Our results indicate that microplastics in forest soils primarily originate from atmospheric deposition. Forests are therefore good indicators of microplastic pollution in the air," says Weber. The study demonstrates for the first time the direct connection between atmospheric inputs and the storage of microplastics in forest soil.
The findings are not only relevant for environmental protection: "Forests are already threatened by climate change, and our results suggest that microplastics could now pose an additional threat," explains Weber. Furthermore, with regard to potential health risks, it is crucial that the study confirms the global transport of microplastics in the air and thus also in the air we breathe.
publication
Weber, Collin J. & Bigalke, Moritz (2025): Forest soils accumulate microplastics through atmospheric deposition . In: Nature Communications Earth & Environment , 6. DOI: 10.1038/s43247-025-02712-4
(Darmstadt - Red/Tud)
