Nanoplastics in forests: Exploring the effects of nanoplastics on forest soils and tree physiology (NanoPlast)

The fate of plastic in the environment is of global concern, because its production recently has increased strongly and it accumulates in terrestrial and aquatic ecosystems. Although some knowledge on its role in aquatic and terrestrial ecosystems was gained in the recent decade, hitherto very little is known about the impact of micro and nanoplastics in forest ecosystems.

The aim of this pioneering project was to explore if nanoplastics are taken up by forest trees species through leaves or roots. In greenhouse experiments, we exposed leaves or roots of seedling of two forest trees species to solutions with highly 13C-labelled polystyrene nanoparticles (13C-nPS, 99 atom%) and examined if they were incorporated in different above- and belowground tissues.

Treated part of the trees for both species showed significant 13C-enrichment, indicating that trees take up nanoparticles. However, the overall 13C signal strength in tissues that were not exposed to the 13C label remained low (Δδ13C<1‰) and was confined to a few seedlings, leaving it ambiguous whether nanoplastic transport occurs or not.

We acknowledge that the new method developed might be not sensitive enough to unequivocally detect mechanisms of nanoplastic uptake and transport at environmentally realistic concentrations.