Nanoplastics \u2014 microplastics that are less than a micrometer in size \u2014 are found all over the world, from Alpine peaks to the deepest parts of the ocean.<\/p>\n
At least 27 million tonnes of nanoplastics are estimated to be floating in the North Atlantic Ocean, weighing more than all wild land mammals combined, reported The New York Times.<\/p>\n
Researchers from the Helmholtz Center for Environmental Research (UFZ), Utrecht University and the Royal Netherlands Institute for Sea Research investigated the prevalence of nanoplastics in the North Atlantic and found the tiny plastic particles at all ocean depths between the subtropical and temperate zones.<\/p>\n
The findings of the study show that nanoplastics are a much bigger part of the marine plastics pollution problem than had been previously thought, a press release from UFZ said.<\/p>\n
\u201cPlastic pollution of the marine realm is widespread, with most scientific attention given to macroplastics and microplastics. By contrast, ocean nanoplastics (<1\u2009\u03bcm) remain largely unquantified, leaving gaps in our understanding of the mass budget of this plastic size class,\u201d the authors of the study wrote. \u201cOur findings suggest that nanoplastics comprise the dominant fraction of marine plastic pollution.\u201d<\/p>\n
Marine plastic waste causes devastating impacts to marine animals, who may become entangled in plastic debris such as bags and nets or ingest smaller pieces, mistaking them for food. Ingested plastic can injure or block the gastrointestinal tract and a small proportion of the tiniest plastic particles can enter the bloodstream by passing through the intestinal wall.<\/p>\n
Until now, quantitative data on microplastics in the world\u2019s ocean was scarce due to the particles\u2019 small size, propensity to change and because they are often hard to distinguish from other particles in the environment using standard methods.<\/p>\n
An expedition by a UFZ and Utrecht University research team aboard the RV Pelagia in 2020 recorded nanoplastic prevalence along a passage between the European continental shelf and the subtropical North Atlantic Gyre. The team took samples from a dozen measuring points: the uppermost ocean layer at approximately 10 meters; the intermediate layer at roughly 1,000 meters; and at 30 meters above the seabed.<\/p>\n
\u201cWith the data from these measuring points, we can make statements about the vertical and horizontal distribution of nanoplastic in the North Atlantic,\u201d said lead author of the study Dr. Du\u0161an Materi\u0107, a chemist with UFZ, in the press release.<\/p>\n
The researchers, led by Materi\u0107, measured concentrations of organic trace gases using thermal desorption and a high-resolution proton transfer reaction mass spectrometer (PTR-MS). They then used these to combust the nanoplastics. Heating them released gases that were able to be quantified with the mass spectrometer.<\/p>\n
Materi\u0107, who developed the method at Utrecht University, explained that each polymer has a unique chemical fingerprint by which both its concentration and identity can be determined.<\/p>\n
Nanoplastics were found at all analyzed depths of the 12 measurement sites.<\/p>\n
\u201cThey are present everywhere in such large quantities that we can no longer neglect them ecologically,\u201d Materi\u0107 said.<\/p>\n
The most frequently detected nanoparticles were polyethylene terephthalate (PET), polyvinyl chloride (PVC) and polystyrene (PS), which are commonly used to make plastic bottles, drinking cups, cutlery and films.<\/p>\n
At almost all measuring points, these types of plastic were detected in the uppermost layer of the ocean.<\/p>\n
\u201cThis is because, on the one hand, the redistribution from the atmosphere occurs via the sea surface and, on the other hand, a lot of plastic is introduced via the estuaries of rivers,\u201d Materi\u0107 explained.<\/p>\n
The intermediate layer of the ocean was dominated by PET nanoparticles.<\/p>\n
Materi\u0107 said more nanoplastics were found in the North Atlantic subtropical gyre, where ocean currents are known to cause surface microplastics to accumulate.<\/p>\n
The lowest nanoplastic concentrations were found near the sea floor. PET nanoplastics were detected at all points measured there, even at depths below 4,500 meters. This nanoplastic most likely came from fragmented synthetic clothing fibers, but could have also come from other unknown processes.<\/p>\n
\u201cNanoplastic and nanoparticles are so small that the physical laws governing larger particles often no longer apply,\u201d Materi\u0107 said.<\/p>\n
To their surprise, the researchers did not find any polypropylene (PP) or polyethylene (PE) \u2014 commonly used in packaging and bags \u2014 at any measuring points., even though they often end up becoming marine plastic waste.<\/p>\n
The total amount of nanoplastics \u2014 approximately 27 million tonnes \u2014 are stored in the top layer of the Northern Atlantic Ocean, up to 200 meters deep, between the temperate and subtropical zones.<\/p>\n
\u201cThis is in the same order of magnitude as the estimated mass of macro- and microplastics for the entire Atlantic,\u201d Materi\u0107 said.<\/p>\n
Ocean nanoplastics have yet to be taken into account in current assessments of total marine plastics.<\/p>\n
\u201cOnly a couple of years ago, there was still debate over whether nanoplastic even exists. Many scholars continue to believe that nanoplastics are thermodynamically unlikely to persist in nature, as their formation requires high energy. Our findings show that, by mass, the amount of nanoplastic is comparable to what was previously found for macro- and microplastic \u2013 at least in this ocean system,\u201d Materi\u0107 said.<\/p>\n
The findings of the study, \u201cNanoplastic concentrations across the North Atlantic,\u201d were published in the journal Nature.<\/p>\n