We already knew that microplastics are found everywhere and nowhere, but thanks to a new laser technique we now also have an idea of the quantity of nanoplastics. And what’s been found so far in bottled water is pretty shocking.
The new technology detected hundreds of thousands of extremely small plastic particles floating in the water bottle. This is ten to one hundred times higher than expected. These types of nanoparticles can easily penetrate the bloodstream, individual cells, and even our brains. The discovery was therefore a great and unpleasant surprise. Because so far we have mostly worried about microplastics, present all over the world: in the soil, in Arctic ice, in drinking water and in our food. But as time passes, plastic breaks down into smaller and smaller particles. While microplastics have a maximum thickness of one micrometer (one millionth of a meter), with nanoplastics they stop at billionths of a meter.
There is a lot of research going on into plastic particles in water bottles, and tens of thousands of plastic particles per bottle have previously been found. But there appear to be many more, as has been ascertained with the help of a new laser microscope. Columbia scientists have so far been able to identify about 10% of these nanoplastics, essentially just shredded microplastic particles.
240,000 plastic particles per liter of water
They found an average of 240,000 plastic particles per liter, which is ten to one hundred times more than previous estimates. The particles are also much smaller than previously thought possible. They are so small that, unlike microplastics, they can easily enter the blood through the lungs or intestinal wall and thus reach all organs, including the heart and brain. They can even penetrate individual cells and reach the fetal body through the placenta.
But no one knows exactly how serious it is. “This was unknown territory for us until recently. We made an estimate through toxicity research, but that’s all,” says researcher Beizhan Yan. “However, this new technology opens doors to a world that has until now been closed to us.”
Frontier of the nanoworld
Natural materials normally decompose into harmless substances, but most plastics do not. They simply break down into smaller and smaller particles of the same chemical material. These divisions can continue until they reach the size of a single molecule. We only knew this recently. In 2018, scientists found that there are approximately 325 plastic particles per liter in bottled water. Subsequent studies have found more and more particles per liter, but the smaller the particles, the more difficult it is to estimate their quantity. Until recently, particles smaller than a micrometer, or at the edge of the nanoworld, were purely conjecture.
“Researchers developed methods to detect nanoparticles, but they had no idea what they were looking at,” explains lead researcher Naixin Qian. This way it was only possible to make a rough estimate of the nanomass, but it was not possible to count the numbers. The researchers were also unable to determine what type of plastic it was. This is now possible with new laser technology, which can resonate specific molecules. For example, in combination with a computer-controlled algorithm, seven common nanoplastics in bottled water were identified. “It’s one thing to detect something, but it’s another thing to understand exactly what you’re detecting,” says Columbia researcher Wei Min, who invented the laser microscope with Qian.
PET
The researchers found, as mentioned, around 240,000 plastic particles per liter of water. Of these, 90% were nanoplastics and 10% microplastics. They found the PET, among other things. This is of course not surprising, because this is what most plastic bottles are made of. Many of these particles are likely to end up in the water when you squeeze the bottle, unscrew the cap, or expose it to heat.
Even more common in the water was another plastic, namely polyamide, a type of nylon. Paradoxically, this is likely due to the plastic filters used to purify the water before it is bottled, Yan explains. Other plastics researchers found in water include: polystyrene, polyvinyl chloride and polymethyl methacrylate, all used in industrial processes.
Number versus mass
Only 10% of the nanoparticles correspond to the seven types of plastic. Scientists have no idea what other particles are. If it were all nanoplastic, there would be more than ten million plastic particles in a liter of bottled water. “But it could be anything,” the researchers write. Much of it can have natural and organic origins. “There is still so much to learn about nanoplastics. In terms of mass, nanoparticles are outnumbered by microparticles, but in numerical terms it is the opposite. And above all it is a question of numbers, because the smaller they are, the more easily they can penetrate the human body”, explains Min.
Arctic snow and the washing machine
Researchers also examine nanoplastics present in other liquids, such as tap water and wastewater from washing machines. Yan found that millions of nanoparticles are released from synthetic laundry with each wash.
The researchers will also identify snow nanoparticles, brought from Antarctica by a British expedition. “It’s not a total surprise to find so much stuff like this,” Qian concludes. “The idea is that the smaller the particles get, the more there are.”
2024-01-10 07:32:53
#ten #times #expected
