German researchers find birch trees can absorb and store microplastics

In Germany, so far, little is known about how microplastics interact with higher-order terrestrial plants. Recent studies have shown that microplastics are taken up in the roots of agricultural plants such as wheat. As part of a cutting-edge interdisciplinary project by Berlin-based art studio, Studio Austen, the research team from the IGB and the German Research Centre for Geosciences (GFZ) has now shown for the first time that longer-lived woody plants absorb and store microplastics in their tissue.

Birch trees (Betula pendula Roth.) already been used to remediate contaminated land because they sequester and store industrial pollutants and heavy metals in their tissues, which subsequently allows the colonization of microbial communities that breakdown polyaromatic hydrocarbons. This tree species’ roots grow close to the soil surface, where microplastic pollution has been shown to be highest, making them a good choice for the study.

The researchers labelled microplastic beads (5-50μm) with fluorescent dye and added them to the soil of potted trees. After five months, they examined root samples using fluorescence and confocal laser scanning microscopy. They found fluorescent microplastic in different sections and layers of the root system. The percentage of root sections with microplastic particles ranged from 5 to 17 per cent in the experimental trees.