The ability of plants to absorb micro- and nanoplastics through their roots and stems raises concerns about how ecosystems will cope when these plastic particles enter the natural environment. But a Danish-Chinese research team offers a new solution: Why not use plants as a natural and environmentally friendly means to collect and break down these plastic particles?

Experts from the Key Laboratory of Wetland Evolution and Ecological Restoration in China and the University of Southern Denmark undertook the research.

Plants and animals absorb nanoplastics

The research is conducted in the context of an alarming global problem. Since the advent of large-scale plastic production, 9 billion tonnes of plastic have been produced, but only 9 percent of this has been recycled.

This causes large amounts of plastic waste that are not taken into account in nature to be broken down into smaller and smaller pieces. Micro- and nanoplastics have become a common environmental problem because these tiny particles can be ingested or digested by animals, plants, and even humans.

Ability of plants to absorb nanoplastics

“We believe that plants can effectively complement existing methods of removing plastic from nature. Many plants absorb or adsorb micro- and nanoparticles, but we need to identify the most effective ones to achieve the best results,” explained the biologist from the University of Southern Denmark, co-author of the study. Written by Elvis Genbo Xu.

Researchers examined the ability of various plants to absorb micro- and nanoplastics. The results show that broad bean (vicia faba) can adsorb 100-nanometer nanoplastic particles through its roots in just two days.

Adsorption is the process of particles adhering to roots; Absorption refers to the uptake of particles by the plant itself. Other plants, such as wheat and lettuce, have been shown to bind and even absorb plastic particles, in some cases incorporating them into their leaves and stems.

Aquatic plants as natural water filters

The researchers found that aquatic plants are of particular interest because they can potentially filter out plastic particles from water bodies where plastic concentrations are generally higher.

Common water hyacinth (Eichhornia blueberry), for example, demonstrated the ability to adsorb plastic particles. Other aquatic plants such as watercress (Lemna minor) have similar potential and can be used as natural filters to capture micro- and nanoplastics in wetlands.

“It would make sense to install plastic absorbent plant strips in places where nano- and microplastics are known to accumulate, such as highways where large amounts of microplastics wear away from car tires,” said Xu. “The arches can act as a filter, capturing plastic particles before they spread over a wider area or are washed into streams by rain.”

Global plastic pollution crisis

However, Xu emphasizes that using plants alone is not enough to solve the global plastic pollution crisis. Micro and nanoplastics are found everywhere in air, water and soil. Since no one can avoid them (they are present in the air we breathe and the water we drink), more than one solution is needed to solve the problem.

Bacteria, fungi and microalgae can play a role in reducing plastic pollution. Although plants are useful, they are only one part of the puzzle.

“Our laboratory experiments have been successful. I’m optimistic that we can expand this to remove particles from the environment, at least the aquatic environment, where aquatic plants have proven to be very effective.”

Using jellyfish to remove plastic particles

Other researchers are working on similar innovative approaches. Jamile Javidpour, a marine biologist and jellyfish researcher at the Faculty of Biology at the University of Southern Denmark, is investigating the possibility of using jellyfish to remove micro- and nanoplastics from the aquatic environment. Jellyfish produce slime, and laboratory experiments have shown that this slime can remove up to 90 percent of nanoplastic particles from water in treatment plants.

“We found that jellyfish slime is extremely effective at removing nano-sized plastic particles. This could be part of the solution; I can imagine using dried jellyfish mucus to create filters for washing machines, for example,” Javidpour said.

These efforts represent a growing body of research on how natural organisms can be used to solve the widespread and persistent problem of plastic pollution. The study was published in the journal Eco-Environment and Health.