Plastics undergo uncontrolled deterioration and fragmentation into microplastics (<5 mm) and nanoplastics (<1 μm) through physicochemical processes in the natural environment. Due to their problems in the food chain, small plastics have been identified as an emerging issue of environmental concern. However, there are still significant knowledge gaps in understanding the uptake and ecological effects of micro- and nanoplastics in aquatic plants.

Prof. YANG Yuyi's team from the Wuhan Botanical Garden of the Chinese Academy of Sciences (CAS) and their collaborators from the University of Southern Denmark, Qingdao University, Leiden University, and  the Leibniz Institute of Freshwater Ecology and Inland Fisheries recently traced and quantified the uptake and transport of micro- and nanoplastics in various aquatic plants using europium-doped polystyrene particles.

The researchers showed that micro- and nanoplastics accumulate mainly in the intercellular space of aquatic plants and are transported from roots to leaves via the apoplastic pathway and the vascular bundle.

The floating plant Eichhornia crassipes has a higher uptake capacity of plastic particles than the submerged plant Vallisneria denseserrulata and the emergent plant Iris tectorum.

In addition, a large amount of submicrometre plastic particles accumulate in the roots of aquatic plants, which is a much higher accumulation capacity than is known for terrestrial plants.

Prolonged exposure to relatively high concentrations of plastic particles has no significant adverse effect on the growth of aquatic plants, suggesting a low health risk from plastic particles at currently predicted environmental concentrations.

The unique advantages of aquatic plants in absorbing nanoplastics and their high tolerance to nanoplastic exposure show their great potential for the phytoremediation of fine plastics in freshwater environments.

The study was published in Water Research entitled "Tracing and trapping micro- and nanoplastics: Untapped mitigation potential of aquatic plants" and it was supported by the National Natural Science Foundation of China and the Special Research Assistant Program of CAS.