A new study estimates that upward of 21 million metric tons of three common types of microplastic pollution exist in just the top 200 metres of the Atlantic Ocean, a problem far worse than previously thought.
Researchers took samples at 12 locations over a 10,000-kilometre North–South transect of the Atlantic and found that the three most prevalent marine microplastics (10–1000 µm) were polyethylene, polypropylene, and polystyrene, all commonly used for packaging products.
The plastics found in the top 200 metres represent only 5.3% of the Atlantic Ocean volume and do not include nanoplastics, the study notes.
“[…] Here we show that the ocean interior conceals high loads of small-sized plastic debris which can balance and even exceed the estimated plastic inputs into the ocean since 1950,” states study author Katsiaryna Pabortsava, who researched the issue alongside Richard Lampitt at the National Oceanography Centre in the U.K.
Previous assessments of plastic pollution in the ocean were insufficient with respect to particle size collected and water layer surveyed, the researchers added. Smaller-sized microplastics that are now dominant in oceanic plastic inventory were not included in the estimates of the previous burden of plastics due to common sampling techniques.
The new study measured penetration of plastic particles down to 25 µm in size.
“A direct comparison of our near-surface abundance data with the previous Atlantic studies of microplastic pollution is challenging as nearly all of them applied different sampling and analytical approaches,” the study states.
The study, High concentrations of plastic hidden beneath the surface of the Atlantic Ocean, published last week in the scientific journal Nature Communications, notes that quantifying plastic pollution has proved very challenging. The materials have a very short lifetime yet such a high contribution to the content of global plastic waste.
“[…] The durability of the material that is such an advantage in its use is also a cause for concern when plastic is released into the wider environment due to poor waste management practices,” the study states.
Polyethylene was by far the most prevalent polymer found in the Atlantic, according to researchers. It is often used to manufacture plastic films, bags, and bottles.