Rotifers crush microplastics into nanoparticles: how dangerous is that? – Knowledge

Over years, plastic debris in water breaks down into smaller and smaller pieces that are potentially more dangerous to organisms. Small animals could play a role in this process in a way never before imagined, a research team from China Ocean University in Qingdao reports in the specialized journal. Nanotechnology from nature. Even a single rotifer can produce more than 350,000 plastic nanoparticles each day. Tens of thousands of these transparent multicellular organisms live in some bodies of water, measuring just half a millimeter per liter of water.

Microplastics are particles up to five millimeters in size. Plastic particles that measure less than a micrometer are called nanoplastics. Huge quantities of nanoparticles can be produced from a single piece of microplastic, making the grinding process problematic, says Annika Jahnke, head of the Department of Ecological Chemistry at the Helmholtz Center for Environmental Research in Leipzig. Smaller particles could be mistaken for food and consumed by significantly more marine life.

Compared to microplastics, nanoparticles also have a relatively larger surface area. This makes them more reactive, “so the particles can release chemicals more quickly,” Jahnke says. Plastics sometimes contain toxic additives that supposedly make them softer, harder, more flexible, colored, or fire resistant. Since nanoparticles can also pick up toxins and pathogens from their environment like a sponge, organisms would also absorb more pollutants with them.

Therefore, according to the specialist’s article, nanoplastics are potentially more harmful to the environment and the health of people and other living beings than microplastics. “Recent studies show that very small particles can pass through cell membranes and can therefore remain in the body longer than larger particles,” explains Jahnke. Researchers have already detected nanoplastics in people’s brains, blood, uterus and breast milk.

Other aquatic creatures also mistake plastic waste for food.

Rotifers apparently mistake plastic for their natural food. Otherwise, they crush and grind algae or organic waste with their chewing stomach. The research team led by Baoshan The group observed what was happening under the microscope: the rotifers particularly ingested particles similar in size to the algae they fed. Shortly thereafter, many nanometer-sized particles accumulated in his digestive tract, which were eventually excreted. Other aquatic inhabitants also confuse plastic waste with their traditional food. This was already described in the case of Antarctic krill in a specialized magazine in 2018.

However, rotifers are much more widespread. There are 2,000 known species worldwide, found in both the sea and fresh water. They are mainly found in temperate and tropical areas of the world, where microplastic pollution is particularly high. The contribution of rotifers to global nanoplastic production is likely to be equally large. For Poyang Lake in China, the country’s largest freshwater lake with an area of ​​nearly 3,700 square kilometers, Xing’s team calculated that rotifers produce more than 13 trillion such nanoparticles each day.

And the plastic problem is likely to get worse, according to OECD forecasts: around 400 million tonnes of plastic are currently produced each year. Plastic production will double by 2050, and even triple by 2060. Currently, only a tenth of plastic waste is recycled; the rest is burned, ends up in landfills or is not controlled in the environment. Micro- and nanoplastics not only come from rotten plastic waste, but also from tire abrasion, dust from the plastic industry, washing machines when it comes to clothing made of synthetic fibers, or microbeads in cosmetics. To combat plastic pollution, international representatives are currently fighting for an agreement at a UN summit in Nairobi. Whether this should ban certain types of plastic or regulate the more than ten thousand chemicals contained in everyday plastics is part of the debate.

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