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We already knew that microplastics were everywhere and nowhere, but thanks to a new laser technology we now have an idea of the amount of nanoplastics. And what has been found in bottled water so far is pretty shocking.
New technology has discovered hundreds of thousands of extremely small plastic particles floating around in your water bottle. This is ten to a hundred times more than expected. Such nanoparticles can easily penetrate the bloodstream, individual cells and even our brains. The discovery was therefore a big and unpleasant surprise. Until now, we have been primarily concerned with microplastics, which occur all over the world: in the soil, in the Arctic ice, in drinking water and in our food. But over time, plastic breaks down into smaller and smaller particles. While microplastics are a maximum of one micrometer (one millionth of a meter) thick, nanoplastics are a billionth of a meter thick.
There is a lot of research being done on plastic particles in water bottles and so far tens of thousands of plastic particles have been found per bottle. But there seems to be much more, as discovered with the help of a new laser microscope. Columbia scientists have so far been able to identify about 10 percent 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 a 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 enter the fetus’s body via the placenta.
But no one knows exactly how bad this is. “This was new territory for us until recently. We made an estimate through toxicity research, but that was it,” says researcher Beizhan Yan. “However, this new technology opens doors to a world that was previously closed to us.”
Limit of the nanoworld
Natural materials usually break down 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 the size of a single molecule is reached. We only knew this recently. In 2018, scientists discovered that there are approximately 325 plastic particles per liter in bottled water. Later studies found more and more particles per liter, but the smaller the particles, the more difficult it is to estimate the amount. Until recently, particles smaller than a micrometer or bordering on the nanoscale were pure conjecture.
“Researchers developed methods to detect nanoparticles, but had no idea what they were looking at,” explains lead researcher Naixin Qian. In this way, only a rough estimate of the nanomass was possible, but numbers could not be counted. The researchers also couldn’t determine what type of plastic it was. This is now possible with new laser technology, which can cause certain molecules to vibrate. For example, in combination with a computer-controlled algorithm, seven common nanoplastics were identified in bottled water. “It’s one thing to detect something, but it’s a completely different thing to understand what exactly you’re detecting,” says Columbia researcher Wei Min, who co-invented the laser microscope with Qian.
DOMESTIC ANIMAL
As mentioned, the researchers found around 240,000 plastic particles per liter of water. 90 percent of these consisted of nanoplastics and 10 percent of microplastics. Among other things, they found PET. Of course, this is not surprising, as this is what most plastic bottles are made of. It’s likely that many of these particles will enter the water when you squeeze the bottle, unscrew the cap, or expose it to heat.
Another plastic was even more common in water, namely polyamide, a type of nylon. Ironically, that’s probably due to the plastic filters used to purify the water before it’s bottled, says Yan. Other plastics the researchers found in the water include: polystyrene, laminated vinyl chloride and polymethyl methacrylate, all of which are used in industrial processes.
Number vs. mass
Only 10 percent of the nanoparticles can be traced back to the seven types of plastic. Scientists have no idea what the other particles are. If it’s all nanoplastics, there are more than ten million plastic particles in one liter of bottled water. “But it could be anything,” the researchers write. A large part can be of natural, organic origin. “There is still so much to learn about nanoplastics. In terms of mass, nanoparticles are in the minority compared to microparticles, but in terms of numbers it is the other way around. And it’s all about the numbers, because the smaller they are, the easier it is for them to penetrate the human body,” says Min.
Arctic snow and the washing machine
The researchers are also studying nanoplastics in other liquids, such as tap water and washing machine wastewater. Yan discovered that millions of nanoparticles are released from synthetic laundry with every wash cycle.
Researchers will also identify nanoparticles from snow brought back from Antarctica by a British expedition. “It’s not a complete surprise that we find so much of it,” Qian concludes. “The idea is that the smaller the particles get, the more of them there are.”
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