Plants could help remove nanoplastics from the environment

Plants have the ability to absorb micro- and nanoplastics in their roots and stems, raising concerns about how ecosystems will manage when these plastic particles infiltrate natural environments. 

However, a Danish-Chinese research team offers a novel solution: why not use plants as a natural and eco-friendly tool to gather and degrade these plastic particles?

Experts the Hubei Key Laboratory of Wetland Evolution & Ecological Restoration in China and the University of Southern Denmark have set out to investigate.

Plants and animals ingest nanoplastics 

The study comes in the context of an alarming global issue. Since the advent of large-scale plastic production, 9 billion tons of plastic have been manufactured, yet only 9 percent of it has been recycled. 

This leaves a huge amount of plastic waste unaccounted for in nature, where it has been breaking down into smaller and smaller pieces. 

Micro- and nanoplastics have become a pervasive environmental problem, as these tiny particles can be ingested or absorbed by animals, plants, and even humans.

Plants’ ability to absorb nanoplastics 

“We believe plants can effectively supplement existing methods for 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 co-author Elvis Genbo Xu, a biologist at the University of Southern Denmark.

The researchers have examined various plants’ ability to take up micro- and nanoplastics. The results show that fava beans (Vicia faba) can adsorb 100-nanometer nanoplastic particles via their roots within just two days. 

Adsorption is a process where particles adhere to the roots, whereas absorption refers to the uptake of particles into the plant itself.

Other plants, such as wheat and lettuce, were also shown to bind or even absorb plastic particles, with the latter incorporating them into their leaves and stems in some cases.

Aquatic plants as natural water filters 

The researchers found aquatic plants to be of particular interest because they can potentially filter plastic particles from bodies of water, where plastic concentrations are often higher. 

The common water hyacinth (Eichhornia crassipes), for example, has demonstrated an ability to adsorb plastic particles. Other aquatic plants, such as duckweed (Lemna minor), have similar potential and could be employed as natural filters to capture micro- and nanoplastics in wetlands.

“It would make sense to establish belts of plastic-absorbing plants in areas where nano- and microplastics are known to accumulate, such as along highways where large amounts of microplastics wear off from car tires,” said Xu.

“The belts could function as a filter, capturing plastic particles before they spread to the wider landscape or are washed into streams by rain.” 

Global plastic pollution crisis

Xu emphasizes, however, that using plants alone is not enough to solve the global plastic pollution crisis. 

Micro- and nanoplastics are found everywhere – in the air, in water, and in soil. Since no one can escape them (they are present in the air we breathe and the water we drink), multiple solutions are required to address the problem. 

Bacteria, fungi, and microalgae could all play a role in reducing plastic pollution. Plants, while helpful, are just one piece of the puzzle.

Despite the complexity of the issue, Xu remains optimistic, especially about aquatic environments. 

“Our lab experiments have been successful. I am optimistic that we can scale this up to remove particles from the environment – at least from aquatic environments, where aquatic plants have proven very effective.”

Using jellyfish to remove plastic particles 

Other researchers are exploring similarly innovative approaches. At the University of Southern Denmark’s Department of Biology, marine biologist and jellyfish researcher Jamileh Javidpour has investigated the possibility of using jellyfish to remove micro- and nanoplastics from aquatic environments. 

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’ve found that jellyfish slime is super effective at removing nano-sized plastic particles. It could be part of the solution – I can imagine using dried jellyfish slime to create filters for washing machines, for example,” Javidpour said.

These efforts represent a growing body of research into how natural organisms can be harnessed to address the widespread and persistent issue of plastic pollution.

The study is published in the journal Eco-Environment and Health.

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