Common Plastics Can Now Biodegrade in Soil Within a Year

Polyethylene and polypropylene — two of the most common plastics on the planet, found in everything from food packaging and drinking straws to bottle caps and car parts — can now be made fully biodegradable in soil within a year, scientists have confirmed in peer-reviewed research.

The breakthrough comes from UK firm Polymateria, which has developed an additive called Biotransformation Masterbatch. When incorporated into standard PE or PP plastics during manufacturing, the additive enables the material to break down into a low-molecular-weight wax after sufficient environmental weathering. That wax is then consumed by naturally occurring soil microbes through metabolic pathways similar to those used to process natural fats.

In tests published in the peer-reviewed journal npj Materials Degradation, treated PE and PP samples achieved more than 90% biodegradation in soil after between 269 and 292 days — well within the threshold used by recognised international standards for complete biodegradability. Conventional PP tested alongside the treated samples did not degrade.

Researchers from Polymateria, Imperial College London, and Malaysia's standards and testing body SIRIM put the materials through laboratory weathering, biodegradation, and ecotoxicity testing. The study found no adverse effects in earthworms, plants, or aquatic organisms — a crucial finding for any technology intended to break down in open environments.

"We now know how plastic materials previously thought to be almost indestructible can safely return to nature," said Dr Jose Jimenez Zarco of Imperial College London. "We are excited to be seeing this approach having real world impact on tackling plastic pollution."

The significance of the technology lies in its potential scale of application. PE and PP together account for around half of all plastic produced globally. Of the plastic packaging waste generated each year, approximately 32% leaks into the environment despite waste management systems — ending up on beaches, in rivers, in agricultural soils, and eventually in the ocean. This is the waste stream that conventional plastics recycling largely cannot reach.

Polymateria's approach is not intended to replace recycling. It is designed as a solution for plastic that escapes the formal waste system entirely — the bottle cap that rolls into a drain, the snack wrapper that blows off a stadium bin, the agricultural film that breaks down imperfectly in a field. For that category of waste, conventional PE and PP can persist for decades or even centuries.

The wider context matters here. Global plastic production has grown exponentially since the 1950s, from around 2 million tonnes per year to more than 400 million tonnes today. The world's ability to collect, sort, and recycle that plastic has not kept pace. Even in wealthy countries with sophisticated waste infrastructure, significant quantities of single-use PE and PP packaging escape into the environment each year.

A biodegradable additive that can be incorporated at the manufacturing stage offers a way to reduce the environmental persistence of that waste without requiring changes in consumer behaviour. The treated plastic looks the same, behaves the same, and performs the same during its useful life. The difference only becomes apparent after it is discarded and exposed to environmental weathering.

The technology is already in commercial use. Polymateria says its additive is being used in products sold in UK stadiums, and more than 300 brands across Asia have adopted it. The peer-reviewed research now provides independent scientific validation of claims that were previously supported only by the company's own testing.

"The research will give policymakers and industry renewed confidence that scalable solutions do exist for the 32% of plastic packaging waste that leaks into the environment each year globally," said Dr Florence Huynh, Polymateria's VP of innovations.

The next frontier will be large-scale field trials outside laboratory conditions, and expanding the technology to other polymer types. But for the two most common plastics in the world, the case has now been made: with the right additive, they can safely return to nature within a year.