Rivers are one of the main sources of pollution by microplastics (5 to 0.0001 mm in size) and nanoplastics (smaller than 0.0001mm) in the oceans. Estuaries, as transition zones between rivers and the sea, are major hotspots for the accumulation of these particles, which are retained in sediments. They pose a threat to aquatic ecosystems given their ability to capture harmful chemicals from the surrounding environment, enter the food-web through ingestion, and bioaccumulate towards higher trophic levels, including valuable commercial species.
These are the main conclusions of the international project "i-plastic" in which the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB) participates, and which has analysed the presence of micro and nanoplastics in estuaries and their adjacent coasts.
The findings of the project show that, of the bivalve species analysed, 85% of mussels and 53% of oysters had ingested microplastics. Estuarine-dependent marine fishes (white mullet, silver mojarra and Brazilian mojarra) were 75% affected, while in coastal regions influenced by the estuarine outflow, 86% of European hake and 85% of Norwegian lobster contained microplastics or synthetic microfibers in their gut. Scientists explain that nanoplastic pollution may be even more serious than microplastics and may poses a greater risk to aquatic organisms, as they can pass through the cellular membrane and harm species living in estuarine and marine environments to a greater extent, as was detected in the case of mussels.
Read more at: Universitat Autonoma de Barcelona
Microplastic debris on Trabucador beach in the Ebro Delta (Spain). (Photo Credit: Michael Grelaud/ ICTA-UAB)