Microplastics in the sea: new method

A particle from the coating of a bridge. Photo: BSH/ Marten Fischer

"Particle abrasion not only occurs in road traffic, but also in shipping, for example," explains BSH scientist Dr. Marten Fischer. "Paint coatings against fouling and corrosion consist mainly of plastics. Weathering and wear result in microplastics - particles smaller than five millimeters". But how many particles end up in the sea?

To elucidate this, a research team combined various chemical-analytical and mathematical-statistical methods. "This allows us to detect different types of particles more accurately and distinguish them from each other reliably. This enables us to better assess the potential risk of particles from coatings and paints for the oceans," explains Dr. Lars Hildebrandt, lead author of the recently published study at Hereon.

Such particles could also increasingly enter the marine environment because of the expansion of offshore wind energy and increasing shipping. The study was funded by the Federal Ministry for Digital and Transport (BMDV) in connection with the BMDV expert network. There, abrasion from transport infrastructure and transport itself is being investigated.

Ships emit paint and coating residues into the water. Photo: BSH

The new method will be applied soon. Scientists will be on board the BSH research vessel ATAIR from April 22 to May 2, 2024 to monitor German marine waters. They will also take water and sediment samples in offshore wind farms and in the German Bight, which they will analyze in the laboratory for particles from paints and coatings.

The sampling campaigns takes place under the umbrella of the European Interreg Northsea project Anemoi. Until the end of 2026, eleven partners from six different countries in the North Sea region will be investigating the material emissions from offshore wind turbines. In addition to particles from paints and coatings, the investigations will also focus on trace metals and organic pollutants.

The expansion of offshore wind energy in the North Sea and Baltic Sea is an important part of the energy transition. The investigations by Hereon and BSH contribute to the continuous improvement of marine environmental monitoring. In this context, the impact of new substances on the marine environment can be assessed and effective measures implemented to reduce their discharge into the oceans.