Published on 15 October 2025
Dymitria is a project led by researchers from IMT Nord Europe, aiming to quantify local microplastics pollution and gain a better understanding of its transfer in the environment. This project is part of a consortium of national projects and will also contribute to harmonizing methods of analysis.
On Sunday December 2, 2024, the 175 countries gathered to negotiate the Global Plastic Pollution Treaty left without reaching an agreement. In the absence of a consensus on the issue of reducing production, talks are set to continue into 2025. This session was supposed to be the last one. In March 2022, these countries had adopted, under the aegis of the United Nations, the goal of drawing up by the end of 2024 a first legally binding treaty to eradicate plastic pollution. And with it, the danger this pollution represents for the environment, the climate and human health would also be eradicated.
At the same time, the reality on the ground shows just how urgent it is to take action. In France and elsewhere, microplastic pollution is found in soil, water and even in the air. These microplastics are defined by the UN Environment Programme (UNEP) as plastic particles measuring less than 5 millimeters. They are derived from the fragmentation of larger plastic waste, or from the direct release of products containing them, such as textile fibers or industrial pellets. The smallest particles are invisible to the naked eye.
Claire Alary, Geosciences researcher at the Centre for Education, Research and Innovation in Materials and Processes (CERI MP) at IMT Nord Europe, and Mel Constant, research engineer at IMT Nord Europe, looked into this as part of the Dymitria project, launched in November 2022, and funded by the French Environment and Energy Management Agency (Ademe) and the French Biodiversity Agency (OFB) for a 3-year period.
This project has several goals. The first is to quantify microplastics pollution and understand how it is transferred from one environment to another. Soil, atmospheric dust, water and sludge from wastewater treatment plants, watercourses, their sediments and their major inputs (storm overflows, stormwater outlets and wastewater treatment plant discharges) are all taken into consideration. Another goal is to help harmonize the methodology used for this type of study. The project is split between metrology studies in the Paris region and quantification in Hauts de France, in an urban environment in the Scarpe watershed near Douai, and in a rural environment in the Planquette watershed.
After 2 years, the first results started to come in. To begin with, soils are contaminated. Fragments of plastic larger than 1 mm (Large microplastics, or LMP) were found in 88% of rural soil samples from the small Planquette agricultural catchment area, and in 100% of urban samples from Douai. And this is despite the small surface areas sampled. In water too, concentrations ranged from one to several dozen LMP per m3. And even the air is not exempt from this pollution, since microplastics are very lightweight and can be carried by the wind. Synthetic fibers have been found in all samples analyzed to date.
300 samples were analyzed in total. And while they still have a long way to go, initial trends show that the concentration of LMP is higher in urban areas than in rural areas, in keeping with the difference in population density and use of these areas.
“These are only preliminary results”, says Claire Alary, “but this omnipresence suggests the existence of underlying contamination that needs to be addressed”. Even more so that the French Ministry of Ecological Transition described this pollution as “a global issue with harmful consequences for human health and the environment”.
Map of the sampling areas for the Dymitria project
To achieve these results, the chosen sampling and analysis methods are crucial, particularly considering Ademe, the funding partner’s goal of harmonizing methodologies.
There are varied techniques to adapt to the environment studied. Sediments from the rivers are sampled on-site by the researchers using a small mechanical grab tool (sediment sampler). Samples of soil are taken around ten centimeters deep. In the water, the particles are captured by nets. Finally, the collectors, funnel-like contraptions fitted onto collection containers, capture microplastics that have traveled through the air.
The samples are then taken to a laboratory. The LMPs are sorted by sieving, measured and then put into six categories: fibers, fragments, films, foams, beads and pellets. Particles smaller than 1 mm (small microplastics, SMP) are separated by density before then being treated with chemicals and observed under a microscope.
Both types of particles are also subjected to infrared analysis to determine their chemical composition. Thanks to a European grant, Mel Constant was given the opportunity to travel to Aalborg University in Denmark. He brought with him samples of microparticles smaller than 300 μm to test other treatment and analysis protocols.
These methodological considerations are an integral part of the Dymitria project. To date, there is no normative or regulatory framework for monitoring and assessing microplastics. This means there are diverse methodologies being implemented, which poses a problem when it comes to comparing data. Since December 2022, Ademe and the OFB have been providing funding for four research projects, including the Dymitria project, to address this issue on a national scale. The team will be participating in drafting a metrology report with Ademe.
The team intends to publish their work once completed, and is already actively involved in raising public awareness on the topic, at the Fête de la Science for example. This is a major issue, since any microplastics found in the soil we cultivate, the water we drink and even the air we breathe end up in our bodies. This has harmful effects on health that are still poorly understood.
Towards a moral code in reindustrialization
