Nexans supports an unprecedented campaign to measure plastic pollution in the oceans

The Nexans - Art et Fenêtres Imoca sailboat is equipped with a microplastics sensor. Its mission is to measure plastic pollution in the oceans during the races in which skipper Fabrice Amedeo takes part.

The measurement campaigns are analyzed by scientists from the University of Bordeaux and Ifremer. This Monday they unveiled the results of the measurements at a precision level of 100 microns, one year after announcing the results of measurements at 300 microns.

This is a large scientific study supported by Nexans. During the races in which he participates, the sailor Fabrice Amedeo carries out a series of measurements for the scientific community. The microplastics sensor of the Imoca Nexans - Art et Fenêtres has three filters that are changed every 24 hours during the race: 300 microns, 100 microns and 30 microns. 53 samples were taken in the Atlantic Ocean during the last Vendée Globe, corresponding to approximately 53 days of sailing.

The conclusions of the analysis of the 300 µm filters revealed that the surface waters of the Atlantic Ocean are twice as polluted by cellulose fibers as by microplastics. The different teams led by Enora Prado, Researcher at Ifremer Brest, Lab. LDCM, Jérôme Cachot, University Professor at the University of Bordeaux, Lab. EPOC, Sophie Lecomte, CNRS Research Director, Lab. CBMN and Christophe Maes, IRD Research Fellow, Lab. LOPS, presented this Monday in Obernai, headquarters of Hager Group, another partner of the project, the conclusions of the study of 100 microns filters.

The analyses indicate a significant presence of cellulose fibers in the filters: they are 40 times more concentrated on the 100 µm sieves with a distribution in the water column almost equivalent to that of microplastics.

Same trend for microplastics: the analysis shows that a greater variety of plastics is detected on 100 µm sieves than on 300 µm sieves. The microplastics particles are 18% polyethylene terephthalate (PET) and 16% polyethylene (PE).

Another striking fact is that 100% of the samples from the 100 µm sieves contain microplastics compared to 64% for the 300 µm sieves. The average concentration is 38 particles/m3 (34 times higher than for particles larger than 300 µm). This can be explained by a faster fragmentation of certain types of plastic into very small particles due to biological, chemical and physical processes such as abrasion, UV action or biodegradation. "We expected it, but we had little idea of the multiplier coefficient", says Enora Prado.

By going from an analysis of 300 to 100 µm, the presence of microparticles (cellulose fibers and microplastics fragments) increases, and the proportion of microplastics is also on the rise: at 300 µm there are twice as many cellulose fibers, at 100 µm the proportion is 54% cellulose fibers and 46% microplastics.

This scientific project supported by Nexans represents an unprecedented opportunity for the scientific community to collect and analyze microplastics of different size classes present in surface ocean waters for which little data is currently available.

Jérôme Cachot says: "overall, this is a relatively new playing field for the scientific community and one that needs to be addressed urgently given the constant increase in global plastic production. Mapping offshore marine waters is a challenge because it covers huge geographical areas for which there is very little data on plastic pollution. The objective is to model the dynamics of plastic pollution: the transport of these particles, the sources of production and the areas of accumulation. As we cannot act everywhere at the same time, it is important to identify the main sources of plastic pollution in order to know where to act first".