In the first 200 meters of surface of the Atlantic, 27 million tons of nanoplastics could be found of which we had no trace so far.
They call it The “missing plastic paradox”: In the ocean waters, only a small amount of all plastic that is estimated has reached the sea in recent decades is found today.
Now we know where at least a part of that disappeared plastic is over: always in the oceans, but in the form of nanoplastics. According to a study published on Natureonly in the upper layer of the North Atlantic Ocean would there be something like 27 million tons of nanoplasticswhose presence we have long been unaware.
Nanoplastics in the Atlantic: how were they discovered?
Most plastic pollution studies in the seas had focused so far on macro and microplastics (plastic fragments of a thickness of less than 5 millimeters), easier to study. Estimate the quantity of nanoplastics (the particles of lower size to a micrometer, i.e. one millionth of the metro) It is a titanic enterprise Because these fragments are often difficult to distinguish from other environmental pollutants, and degrading they change easily.
A group of scientists from the Nioz Royal Netherlands Institute for Sea Research, the Dutch Oceanographic National Oceanographic Institute of the University of Utrecht and the Helmholtz Center for Environmental Research in Germany worked for a month on the research ship RV Pelagiafacing a scientific expedition to the North Atlantic from the Azores to the European continental platform. They collected water samples In 12 different locations on three depths (around 10 meters, around 1,000 meters and 30 meters above the seabed) and filtered by water all the larger particles of a micrometer.
The scientists then dried the remaining particles and warmed them so that they freed gas. Since each polymer has a well -recognizable chemical signature, the analysis of the gases with mass spectrometry has made it possible to trace the type of substance and its concentration.
Nanoplastics in impressive quantities
Large quantities of nanoplastics have been found everywherein all measurement sites, in the upper layer of the oceanfor various reasons: the larger plastic particles disintegrate due to the effect of sunlight, they reach the seas through the water of the rivers or reach the upper layer of the oceans directly from the airor through the rains (damp deposition) or with normal gravitational deposition (dry deposition).
The Nanoplastics found more frequently are those of Tereftolato Polyethylene (PET), Polistirene and Polivinilcloride (PVC), the polymers used in bottles and plastic cutlery, packaging, food packaging, textiles, pipes and electrical cables. In the intermediate layer the nanoplastics in pet prevail, while the lowest concentrations of nanoplastics are in the lowest layer near the seabed: here too PET has been found in each measuring site, perhaps the product of the degradation of textile fibers.
The only common plastics that have not been traced in the form of nanoplastics are polyethylene and polypropylenecommonly used in plastic envelopes that contaminate the oceans – perhaps, they hypothesize researchers, because they are altered in a way that makes them escape the analysis techniques studied, or because they are involved in oceanic sedimentation dynamics still little known.
Impossible to remove
By extending the results of the areas analyzed to the rest of the ocean, the group concluded that, Only in the first 200 meters of depth of the North Atlanticfrom the temperate to the subtropical area, There are approximately 27 million tons of nanoplasticsso thin that the physical laws that govern the movements and the deposition of the greatest plastics do not always follow.
This means that nanoplastics constitute A huge portion of the ocean plastic pollution which has not been taken into account in the current assessments on plastic in the seas, “of the same order of magnitude of the estimated macro mass and microplastics of the entire Atlantic”, explains Dušan Matterić, a chemist of the Helmholtz Center for Environmental Research (Germany) at the head of the study.
“Just a couple of years ago, a debate was still underway on the very existence of nanoplastics (…). “Our discoveries show that, as regards mass, the amount of nanoplastics is comparable to that previously found for macro and micro plastics, at least in this ocean system”.
