Your laundry is shedding more than just lint.
Washing machine wastewater is one of the top sources of microplastics, with a single unit in a four-person household producing up to 500 grams a year as synthetic fabrics break down.
Those pesky particles — smaller than a grain of rice — make their way into everything from makeup and cleaning products to the food on our plates, eventually winding up in our bodies and posing potential health risks.
Now, German scientists have developed a filter that traps nearly all the microplastics escaping our spin cycles, and it takes inspiration from a surprising source: fish.
Certain species, like mackerel, sardines, and anchovies, feed by filtering the water. They swim with their mouths open, trapping tiny plankton using their gills.
“We took a closer look at the construction of this system and used it as the model for developing a filter that can be used in washing machines,” Dr. Alexander Blanke, one of the lead researchers, said in a press release.
These fish have a gill-arch system shaped like a funnel — wide at the mouth and tapering toward the throat. It has comb-like structures and tiny teeth, creating a natural mesh.
“During food intake, the water flows through the permeable funnel wall, is filtered, and the particle-free water is then released back into the environment via the gills,” Blanke explained.
“However, the plankton is too big for this; it is held back by the natural sieve structure,” he continued. “Thanks to the funnel shape, it then rolls towards the gullet, where it is collected until the fish swallows, which empties and cleans the system.”
This design keeps the filter from clogging while removing nearly all the plankton from the water — both crucial qualities for a microplastic filter.
“The filter systems available so far, however, have various disadvantages,” said Dr. Leandra Hamann, the study’s lead author. “Some of them quickly become clogged, others do not offer adequate filtration.”
In search of a better solution, Hamann and her team recreated the fish’s gill-arch system, adjusting both the mesh size of the sieve and the angle of the funnel.
“We have thus found a combination of parameters that enable our filter to separate more than 99% of the microplastics out of the water but not become blocked,” Hamann said.
The trapped microplastics collect in the filter and are suctioned away several times a minute.
Hamann said the material can then be pressed in the machine to squeeze out any remaining water, forming a dry pellet that can be removed every few dozen washes and thrown out with regular trash.
Notably, the fish-inspired filter doesn’t require any elaborate mechanics, making it inexpensive to manufacture, the researchers said.
The team has already applied for a patent in Germany and hopes manufacturers will integrate the filter into future washing machines.
This could help curb the spread of microplastics from textiles, a growing concern as evidence mounts that these particles may pose risks to human health.
Microplastics enter our bodies through ingestion, inhalation and skin contact. They’ve been detected in human placentas, kidneys, lungs, livers, testicles and blood, among other organs and tissues.
While more long-term research is needed to fully understand their effects, studies suggest these tiny fragments can damage our intestinal cells, trigger inflammation and disrupt the balance of bacteria in our guts.
These changes are suspected to harm reproductive, digestive and respiratory health, and may increase the risk of serious conditions such as heart disease, stroke and certain cancers.
