We still have a lot to learn about the « plastic empire » — pollution detected 40 years ago in every corner of the world.
Up to 11 million tonnes of plastic are released into the ocean each year, according to current scientific models. The number of plastic fragments in the ocean is estimated at 5,000 billion—equal to the total quantity of zooplankton in the Mediterranean—one of the world’s most polluted seas.
Why does this massive quantity of plastic, undoubtedly toxic, flow increasingly into the waters of the Blue Planet? The schooner Tara, with her partners and sponsors, set out to answer this question in 2019.
After 10 years of research (since 2010) assessing the amount of plastic in the ocean, the CNRS, Tara Foundation teams and sponsors decided to investigate the origins of the plastic flux. In this relatively virgin field of research, the Tara mission was a pioneer. For 7 months, (from May to November 2019), the schooner travelled along the major European maritime fronts and sailed up 9 major rivers taking samples.
Led by the Tara Ocean Foundation, this first mission dedicated to plastic pollution in European rivers brought together 17 research laboratories that are currently working on the data. True exploration, this scientific research was led by Jean-François Ghiglione, ecotoxicologist at the Microbial Oceanography Laboratory in Banyuls-sur-Mer (CNRS):
« We wanted to see what is actually happening in our European rivers, said to be draining no less than 600,000 tonnes of plastic per year. This puts us in second place in the world of pollution, just behind Asia, whose rivers are said to be discharging 4 million tonnes of plastic into the seas per year. »
Aboard the schooner, sailors and scientists sailed up the Thames, Elba, Rhine, Seine, Ebro, Rhone, Tiber, Garonne and Loire rivers, reproducing the same protocol for sampling the waters and banks. A total of 2,700 samples were taken at sea near estuaries, at the mouths of the rivers, and then in their beds, upstream and downstream of the first major city encountered. After covering 17,000 kilometres, the crew returned to Lorient, Tara’s home port, having completed this vast sampling of microplastics. The samples are currently being examined by a team of marine biologists, ecotoxicologists, oceanographers, modelers, chemists and physicists. The results of this study are expected in autumn 2022, but already there are some surprising findings.
In day-to-day life
From sea to land
This freshwater expedition, following the 9 major rivers that traverse the countryside, cities and towns of Europe, was a reminder of our often forgotten link with the Ocean.
140million plastic bottles per year discarded in nature in France
« For a long time we thought that transformation of plastics into microplastics happened at sea, under the influence of sun and waves. However, the process also seems to be taking place in rivers and their catchment areas. Our research is making it possible to better understand the phenomena of plastic fragmentation, quantify what comes from rivers, and assess the nature of plastic pollution in order to guide the measures to be taken. »
Jean-François Ghiglione, director of research, CNRS
Common Idea: It’s possible to walk on the “plastic continent”. No! The image of a “continent” suggests the magnitude of the phenomenon, but does not mean dry land.
Researchers speak of plastic “soup”, a mixture of large and small plastics accumulating in certain places at the ocean’s surface.
Assesment
Plastic at sea — the solutions are on land!
Everywhere!
All 2,700 samples collected from the rivers contain plastic, including upstream of cities such as London, Hamburg or Rouen.
Upstream fragmentation
The majority of plastic found in river water samples are in the form of microplastics. This pollution is invisible, impossible to collect, and calls for major actions on land to stop the flow.
Six actions to take ashore
-improve collection and recycling
-reduce single-use disposable plastics
-reduce the number of chemicals and resins added to plastic -reinvent packaging to eliminate toxic polystyrene -reinstate a deposit system for PET bottles
-obtain a United Nations Treaty concerning plastic
