New plastic that dissolves in seawater raises hopes for tackling ocean pollution

Scientists in Japan have developed a new type of plastic that dissolves quickly in seawater, offering a potential breakthrough in the fight against ocean pollution.

The material, created by researchers at the University of Tokyo, is being described as the fastest-degrading plastic of its kind.

The researchers say it can vanish within hours in saltwater or soil without leaving behind harmful microplastics.

Plastic pollution has emerged as a major health hazard, with microplastics now found in human organs and even brain and bloodstream. The UN has warned that plastic waste entering the oceans could triple by 2040 unless urgent action is taken.

While recycling rates remain dismally low, especially for single-use plastics, scientists and innovators are racing to develop alternative materials that break down more easily or bypass the problem altogether.

In a laboratory demonstration, a small piece of the material disintegrated in a tub of seawater after only an hour of stirring, according to a study published in the journal Science.

Scientists say the material maintains the strength of traditional petroleum-based plastic, but, when exposed to salt, breaks down into its original components, which are then digested by naturally occurring bacteria.

The breakthrough comes at a time when plastic waste continues to flood the world’s oceans.

Global plastic pollution is estimated to triple by 2040, with the UN Environment Programme warning that up to 37 million tonnes of waste could enter marine ecosystems each year.

The innovation was announced ahead of the World Environment Day on 5 June as countries prepare for the next round of negotiations on a global plastics treaty in August, after failing to agree a deal in December.

While the dissoluble plastic is not yet commercially available, the researchers are working on developing coatings that will allow the material to be used like conventional plastic in packaging and other everyday applications without compromising its rapid degradability in nature.

Project lead Takuzo Aida said the team had already seen interest from the packaging industry. “Children cannot choose the planet they will live on. It is our duty as scientists to ensure that we leave them with the best possible environment,” he told Reuters news agency.

What sets this new plastic apart is its ability to disappear not just in water but also in soil which contains salt. A 5cm piece can degrade completely after about 200 hours in moist earth, according to the researchers.

It is also non-toxic and non-flammable and emits no carbon dioxide as it breaks down, the researchers say.

But experts warn that any plastic alternative will need to overcome challenges like beating the low cost of traditional plastic and the lack of infrastructure for production. There have been several technological breakthroughs in plastic alternatives in recent years but scaling them for wider commercial use has been a challenge.

Scientists in Switzerland recently created a tough, biodegradable film made from the living fibres of a mushroom.

This fungi-based material is not only compostable but also edible and self-reinforcing, potentially useful for packaging or cosmetics.

In 2022, scientists at Rutgers University, in partnership with Harvard University, created an antimicrobial and biodegradable spray-on protective coating for produce and other food items. Made out of plant cellulose, the spray is designed to be rinsed off with water and, according to the scientists, degrade in soil within three days.