Scientists have come up with an easy way to get rid of microplastics in drinking water
Micro- and nanoplastics are found everywhere: in soil, water and air. Previously, researchers have proposed many original options for removing these ubiquitous particles, but recently it turned out that one effective method of cleaning drinking water from them has been used by people since ancient times.
About a long familiar solution told experts in the field of biomedical engineering and the study of microplastics from the Medical University of Guangzhou and Jinan University (both in China). Their experiment showed that boiling water with high calcium content (also called hard water) removes more than 80 percent of microplastics from it.
For the study, which was published in the journal Environmental Science & Technology Letters, the Chinese city of Guangzhou took samples of tap water of different hardness. Three types of plastic particles - polystyrene, polyethylene and polypropylene - ranging in size from 0.1 to 150 micrometers were added. Then the samples were boiled for five minutes, and then cooled down and measured the content of plastic particles in the water.
The fact is that during boiling in mineral-rich hard water appears insoluble calcium carbonate CaCO3, simply put, scale. The researchers hypothesized that it could bind plastic particles and precipitate together with them.
This is what happened in the experiment. The cleaning effect was strongest in samples with higher hardness, which contained 300 milligrams of CaCO3 per liter. Boiling removed up to 90 percent of the plastic microparticles in the water. In soft water (less than 60 milligrams of CaCO3 per liter), boiling removed 25 percent of the added microplastics.
Thus, the researchers demonstrated that the task of cleaning drinking water from microplastics can be solved not only with the help of expensive modern filtration systems, but also such a simple and time-tested method as boiling, which also provides disinfection.
The scientists added that if scale residue with plastic "encapsulated" in it floats on the surface, it can be removed by pouring water through a paper coffee filter.
The ubiquity of micro- and nanoplastics is a growing global concern because of the potential health hazards of these particles. Because of their tiny size (from less than five millimeters to one micrometer or less), they can enter the body through the mouth, nose, and other exposed body parts.
However, there is no consensus among scientists about them. Some argue that the accumulation of microplastics can lead to various pathologies, including plastikosis, in which there is scarring in the tissues of internal organs and digestion is disturbed. At the same time, the WHO has previously stated that they have not found convincing evidence of harm from microplastics in drinking water.