“Microplastics will continue to circulate in our ecosystems for millennia,” according to CNRS research

CNRS researchers in Toulouse have just built the first model of the life cycle of microplastics found in the Pyrenees. They concluded that these particles are likely to remain in circulation for millennia, even if we drastically reduce their production.

Following the discovery of microplastics in the Garonne, the air of the Pic du Midi or the snow of the Pyrenees, a group from the CNRS in Toulouse built the first comprehensive model of the life cycle of microplastics. And their findings are, not surprisingly, alarming.

“We wanted to know how much of the big plastic turns into smaller plastic, which is more dangerous to our health and biodiversity, and where it goes next.”Gaël Le Roux, CNRS research director at the Functional Ecology and Environment Laboratory, says.

As a first step, the researchers conducted a synthesis to estimate the amount of microplastics present in the deep ocean, marine sediments, beaches and continental surfaces. Other recent studies have determined atmospheric emission and deposition fluxes, ocean sedimentation rates, and the rate at which plastics break down into microplastics.

All these estimates allowed the first conceptualization of the life cycle of plastics for 2015 as a reference year. For example, researchers have observed that the spread of plastics through rivers is greater than the spread of land waste.

We talk a lot about plastic floating in the oceans, but we realized that there is 10,000 times more plastic on our continents than on the surface of the oceans.

Gaël Le Roux, CNRS research director of the Functional Ecology and Environment Laboratory

The team then developed a mathematical model of the life cycle of plastics to simulate the process of dispersal into the environment, air, oceans and soil since 1950.

“Even if we drastically reduce plastic production and improve its management in the coming decades, the model shows that microplastics will continue to circulate in our ecosystem for millennia.”adds the researcher.

Even under the most optimistic plastic waste reduction scenarios, the Earth system will take hundreds of years to digest it.

Gaël Le Roux, CNRS research director of the Functional Ecology and Environment Laboratory

Not surprisingly, research advocates more sustainable management of old and new waste in urban, industrial and agricultural settings to limit the future spread of microplastics. “This type of model shows that our human activity has consequences for hundreds of years and we need to act urgently.”adds the researcher.

In France, the anti-waste law for a circular economy aims to end the marketing of single-use plastic packaging by 2040. After its introduction in 2020, several plastic products began to disappear, such as straws, for single use. Blades or stirrers prohibited from January 1, 2021.

Although they are going in the right direction, given the urgency of the situation, these measures are not only very insufficient, some of them are even counterproductive. Fast food brands, for example, will be required to switch to reusable tableware for on-premises meals from January 1, 2023. That’s why McDonald’s has chosen to replace disposable cardboard packaging with… plastic, washable packaging. Tritan, more specifically, is a very strong plastic derivative that keeps being washed repeatedly. The road to a plastic-free world still seems very (very) long.