2023-07-12 17:00:11
The pollution by plastics and microplastics It has had a worldwide impact and has come to affect remote places where human presence is minimal.
A study published in Nature confirms, for the first time, that concentrations of plastic found in various freshwater bodies they are higher than those of some oceanic gyres that accumulate large amounts of debris and are known as plastic islands.
The research, led by the University of Milano-Bicocca, includes the participation of the National Museum of Natural Sciences (MNCN-CSIC) and the Institute for Environmental Diagnosis and Water Studies (IDAEA-CSIC), both of the Higher Council for Scientific Research (CSIC). ), as well as researchers from the University of A Coruña, among other Spanish centers.
The Sau Reservoir, in Catalonia, is one of the lakes studied. | Quico Llach
“Lakes are like sentinels of pollution, since they end up accumulating plastic waste that is dispersed through various sources such as reservoirs or the atmosphere. In addition, once they reach their waters, the lakes can retain, modify and transport plastic waste through the hydrographic basins towards the oceans”, contextualizes the IDAEA-CSIC researcher, Miguel Cañedo-Arguelles.
Among the lakes where the greatest contamination by plastic waste has been identified is the Maggiore (Italy), Lugano (between Switzerland and Italy), Tahoe (USA), Neagh (United Kingdom) or Pantà de Sau, in Cataloniawhich is one of those that comparatively shows the worst levels of microplastics.
The water masses studied in Galicia (the Abegondo-Cecebre reservoir, the Doniños coastal lagoon and the Meirama lake) are in line with what is observed in global trends.
Lakes are like sentinels of pollution. Plastic waste that is dispersed through sources such as reservoirs or the atmosphere ends up accumulating in them.
Miguel Cañedo-Argüelles (IDAEA-CSIC)
These lakes act as the main sources of drinking water of the surrounding populations. They are also fundamental areas for their respective economies since numerous recreational activities take place in their surroundings.
“The relevance of these results lies in the fact that, in addition to negatively impacting the drinking water we need, plastic pollution has harmful effects on aquatic organisms and the functioning of ecosystems,” he explains. Veronica Navascientist at the University of Milano-Bicocca.
The collaboration of almost 80 researchers has made it possible to take surface water samples, using plankton nets, from 38 lakes located in 23 different countries, spread over 6 continents. This diversity has made it possible to represent different environmental conditions.
In addition to negatively impacting the drinking water we need, plastic pollution has harmful effects on aquatic organisms and the functioning of ecosystems.
Veronica Nava (University of Milano-Bicocca)
“Once collected, the different teams sent the samples to the Italian university where, with technologies such as Raman microspectroscopy, an extremely precise analysis was achieved with which we were able to confirm the polymer composition of the microplastics. Among all that was found, the presence of polyester, polypropylene and polyethylene”, points out the MNCN-CSIC researcher miguel matias.
“In addition, we have been able to identify determining factors such as population density, urbanization, the size of the basins and the retention times of water, which explain the vulnerability of lakes and reservoirs to contamination by plastics”, continues Matias.
Above left: Large piece of longline at 80 m depth in one of the most remote islands in the world: São Paulo Archipelago, off Brazil / Above right: Fire urchin (Asthenosoma varium) clings to a fishing line while camouflaging with a piece of blue plastic bag at about 130 m depth in the Philippines / Bottom left: Plastic bag entangled in a coral in the Philippines at about 10 m depth / Bottom right: Fishing lines entangled and breaking Dendrophylliid corals at 70 m depth depth in Cape Verde. / Photos: Luiz Rocha
The long haul of plastics
“Plastic that accumulates on the surface of aquatic systems can promote the release of methane and other greenhouse gases. These residues can interact with the atmosphere, the biosphere and the lithosphere, affecting the biogeochemical cycles”, explains Nava.
“The circulation between the different elements of the earth, which pass from living matter to inorganic matter through chemical reactions, is not yet fully understood, and a holistic evaluation of plastic pollution in lakes is necessary,” keep going.
These results demonstrate the global scale of plastic pollution: no lake can be considered truly pristine.
These results demonstrate the global scale of plastic pollution: no lake, even those furthest away from human activity, can be considered truly pristine. “This result should prompt us to review the strategies of pollution reduction and waste management processes”, concludes Nava.
The project is part of the international Global Lake Ecological Observatory Network (GLEON), focused on research on the processes and phenomena that are triggered in freshwater environments.
Researchers Veronica Nava and Barbara Leoni during the sampling process. / Veronica Nava
Reference:
Veronica Nava et al. “Plastic debris in lakes and reservoirs”. Nature (2023)
Rights: Creative Commons.
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