For the first time, geoscientists prove that the microplastics are stored in forests

Microplastics and nanoplasty not only pollute our oceans, rivers and fields, but also our forests, according to the geoscientists from TU Darmstadt. Your research will be published in Communication earth and the environment.

According to the new study, harmful microplastics are stored not only in agricultural and urban floors, but also in forests. The majority of tiny plastic particles enter the forests from the air and accumulate in the forest floor.

“The microplastics from the atmosphere are initially based on the leaves of the treetops, which scientists” describe comb-out effect, “explains the main author Dr. Collin J. Weber from the Institute for Applied Geosciences in TU Darmstadt. “Then, for example, the particles are transported into the forest floor in deciduous forests, for example by rain or the autumn sheet.”

There, leaf custody plays a central role in storing pollutants in the forest floor, as the authors further discovered. Although the highest microplastic values ​​were found in the upper, only slightly decomposed leaf screens, large amounts of plastic particles are stored in the deeper layers of the soil. This can be attributed to the decomposition of leaves themselves, but also to other transport processes such as B. organisms involved in the decomposition.

For the survey, the research team of the Ministry of Floor Mineralogy and Soil Chemistry took rehearsals at four forest areas east of Darmstadt in Germany. With a newly developed and adapted analysis method, the scientists were able to measure the microplastic content in soil samples, fallen leaves and atmospheric deposition (the transport of substances from the earth's atmosphere to the surface of the earth) and analyze them chemically using spectroscopic methods. Since the 1950s, they have also produced a model estimate of atmospheric input to determine their contribution to the overall storage in forest soils.

“Our results indicate that microplastics in forest soils come mainly from atmospheric deposition and leaves, which are referred to as a literary case. In contrast, other sources have only a minor influence,” explains Dr. Weber. “We conclude that forests are good indicators for atmospheric microplastic pollution and that a high concentration of microplastics in forest soils indicates a high diffuse input – in contrast to direct inputs such as fertilizers in agriculture – from particles from the air into these ecosystems.”

The study is the first to demonstrate the pollution of forests with microplastics and the direct connection between atmospheric inputs and the storage of microplastics in the forest floor, since these problems have not previously been scientifically examined. The results form an important basis for assessing the environmental risks equipped by microplastics.

“Forests are already threatened by climate change, and our results indicate that microplastics could now be an additional threat to forest ecosystems,” says Dr. Weber. The results can also be relevant for the assessment of health risks, as they highlight the global transport of microplastics in the air and thus also in the air we breathe.