First samples from the Thames

© Aude Boissay / Studio Cui Cui

17 June 2019

Tara went to sea to reach the first European river for sampling: the Thames. Jean-François Ghiglione, scientific director of the Microplastics Mission 2019 shares these first impressions, observations and questions.

A thirteenth stroke of midnight was exceptionally struck by the schooner Tara for her departure from Saint Malo. Some faithful friends made the trip in the middle of the night to wish us good luck. We pull our rain gear over our ears and everyone is on deck with a big smile for the start of the Microplastics Mission 2019. We congratulate each other for all the preparatory work it took to launch this new mission. Let’s go hunting for microplastics!

The sea is calm to slightly agitated — ideal conditions for testing the equipment. The dress rehearsal will last two days. Time to create that special link between sailors and scientists; time for everyone to find their bearings. Protocols are discussed, materials are secured, labels are affixed so that the precious samples can then find their way to the 12 partner laboratories.

The famous London smog welcomes us for our first sampling at sea, off the Thames estuary. We are a little tense, afraid to botch this first sampling. The sea has considerable swell, but the crew is experienced in deploying the Manta net we will use to filter microplastics from more than 100,000 liters of water. It will take 2 hours of sampling and 3 hours of processing to finish this first station. But the tide doesn’t wait, and we must leave for the second station in the estuary before we’ve finished the first. Our work day will end at 3 in the morning. We’re not yet broken in!

Sampling stations will follow one another along the Thames. We’ll use a light boat to collect samples below London while the schooner Tara remains moored close to the famous Tower Bridge. Later, all the equipment will be transported ashore by the team to avoid the locks and to complete the sampling above London, which will serve us as a reference to evaluate the effect of this large city on pollution.

Echantillons_mains_Alexandra_Ter_Halle@Noëlie_Pansiot-12 2

Alexandra Ter Halle, scientific on board Tara, studies the first samples of microplastics © Noëlie Pansiot / Tara Ocean Foundation

Under the microscope, microplastics are present. By the hundreds. Many are microbeads used in cosmetics. There are so-called ‘mermaid’s tears’, granules that come directly from plastic manufacturers. There’s much more plastic than what the team usually observes at sea. Fibers from clothing, expanded polystyrene pellets from food trays, pieces of plastic bags. A lollipop stick and some candy packages are the only ‘big’ garbage collected. Microplastics (< 5 mm) make up more than 90% of the harvest. The first observation of this mission: most plastics arriving at sea from the Thames are already in the form of microplastics. Is this an exception or a generality? What about other rivers in Europe? The schooner is already on her way, continuing the journey to answer this question.

 Jean-François Ghiglione

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