“Plastic rain” has been found to be falling onto forests as high concentrations of microplastics accumulate in the atmosphere.
Researchers at TU Darmstadt in Germany said the research highlighted the potential heath risks from airborne microplastics.
The plastic rain was also a threat to the forests themselves, which were already impacted by climate change.
The study found that, while it was known that harmful microplastics were stored in agricultural and urban soils, tiny microplastics were now confirmed in forest leaves.
“The microplastics from the atmosphere initially settle on the leaves of the tree crowns, which scientists refer to as the ‘comb-out effect’,” lead study author Dr Collin J. Weber from the Institute of Applied Geosciences at TU Darmstadt said.
“Then, in deciduous forests, the particles are transported to the forest soil by rain or the autumn leaf fall, for example.”
For the survey, the research team from the Department of Soil Mineralogy and Soil Chemistry took samples at four forest sites east of Darmstadt in Germany.
They also produced a model estimate of atmospheric inputs since the 1950s to determine their contribution to total storage in forest soils.
“Our results indicate that microplastics in forest soils originate primarily from atmospheric deposition and from leaves falling to the ground, known as litterfall,” Dr Weber said.
“We conclude that forests are good indicators of atmospheric microplastic pollution and that a high concentration of microplastics in forest soils indicates a high diffuse input – as opposed to direct input such as from fertilizers in agriculture – of particles from the air into these ecosystems.”
The full publication is:
Weber, Collin J. and Moritz Bigalke: ‘Forest soils accumulate microplastics through atmospheric deposition’, in: ‘Nature Communications Earth & Environment’ 6, DOI: Link to research paper
