2023-11-15 16:30:13
Estuaries, being transition zones between rivers and the sea, are important sources of accumulation of microplastics, which are retained in the sediments. They pose a threat to aquatic ecosystems due to their ability to capture harmful chemicals from the environment, enter the food chain through ingestion and bioaccumulate towards higher trophic levels, including species of high commercial value.
An international project called i-plasticin which the Institute of Environmental Science and Technology of the Autonomous University of Barcelona (ICTA-UAB) participates, has analyzed the presence of micro and nanoplásticos in estuaries and adjacent coasts. His conclusions indicate that all aquatic species from the mouths of rivers to the Mediterranean Sea and the Atlantic Ocean are contaminated by microplastics. The molluscs They are the most affected due to their ability to filter water. Rivers are one of the main sources of microplastic (5 to 0.0001 mm in size) and nanoplastic (less than 0.0001 mm) pollution in the oceans.
The project’s conclusions show that, of the bivalve species analyzed, 85% of the mussels and 53% of the oysters had ingested microplastics. The Marine fish of the estuaries (white mullet, silver mojard and Brazilian mojard) were affected by 75%, while, in the coastal areas close to the mouths, 86% of the European hake and 85% of the Norwegian lobster contained microplastics. Scientists explain that pollution from nanoplastics can be even more problematic than from microplastics and can represent a greater risk for humans. aquatic organisms, since they can cross the cell membrane and damage them to a greater extent. This has been detected in the case of mussels.
Pollution is omnipresent in estuaries and adjacent coasts, both in Mediterranean, tropical and temperate zones.
Patrizia Ziveri, ICTA-UAB oceanographer
“Pollution is omnipresent in estuaries and adjacent coasts, both in Mediterranean, tropical and temperate zones,” he indicates. Patrizia Ziveri, oceanographer at ICTA-UAB and project coordinator, who recalls that the amount of particles accumulated in the sediment has increased in recent decades at the same rate as the global production of plastics and that, since 2000, the particles deposited at the bottom of the sea have tripled.
This pollution poses an additional global threat to coral reef systems at all depth levels, since it causes a reduction in its growth.
Areas close to cities
Pollution is especially high near urban centers and the discharge areas of wastewater treatment plants, from where microfibers, the most common type of microwaste, are discharged into the outlets. When they reach the seabed, the particles do not degrade due to lack of erosion, oxygen and light. “Plastics from the 1960s still remain at the bottom of the sea, leaving traces of human pollution,” he says. Michael Grelaudoceanographer at ICTA-UAB and also coordinator of this project subsidized by JPI-Oceans, in which universities from Italy, Portugal, Brazil and Spain.
Plastics from the 1960s still remain at the bottom of the sea, leaving traces of human pollution
Michael Grelaud, ICTA-UAB oceanographer
Particles that do not settle on the seabed can be transported by currents and tides hundreds of kilometers in a few months. “A microplastic from mouth of the Ebroin the northwestern Mediterranean, can reach Sicily, in Italy, in just six months,” says Ziveri.
Researchers emphasize that bioremediation (consisting of the use of living organisms to eliminate contaminants from water) is one of the few viable options to reduce pollution in coastal marine environments. “Laboratory experiments showed that different species of filter feeding animals They eliminated almost 90% of the microplastics present,” he concludes.
Rights: Creative Commons.
#aquatic #species #river #mouths #contaminated #microplastics