This article first appeared at n-tv.de

Anyone who regularly drinks water from plastic bottles is consuming a large amount of microplastics. A new US study published in the journal “Proceedings of the National Academy of Sciences” shows that there are far more plastic particles in table or mineral water than previously thought. Accordingly, bottled water can contain more than 200,000 nanoplastic particles per liter.

“This is ten to a hundred times more than previous estimates, which were primarily focused on larger microparticles,” reports Naixin Qia, co-author of the study. According to the analysis, nanoplastics, which were previously invisible using common methods, make up on average around 90 percent of the total plastic particles detected.

Nanoplastics are particles less than one micrometer in diameter. Due to their small size, the small particles have so far remained largely undetected. Thanks to a special research method, Qian and her team were able to determine the extent of contamination in bottled water more precisely.

To do this, they first analyzed nanoparticles using a special microscopy method, which provides information about the type of plastic. The team then trained an adaptive algorithm to recognize nanoparticles from seven different plastics. The researchers then examined table water made from PET bottles from three different American manufacturers.

Contrary to expectations, the majority of the nanoparticles detected were not made of PET (polyethylene terephthalate) - even though the water bottles examined were made of this material. Rather, polyamide made up the majority of the nanoplastic. This plastic probably gets into the water through water treatment and filtering, as plastic membranes are often used at this point, according to the researchers.

"Nanoplasty is particularly toxic because its smaller size makes it easier for it to penetrate deep into the human body," warn Qian and her colleagues. This makes it even easier for the particles to penetrate human tissue and organs and cause cell damage.

The contamination of table and mineral water by nanoplastics may be even greater. Despite the new methodology, Qian and her team only managed to identify 10 percent of the nanoparticles discovered as plastic particles and thus determine the 200,000 particles per liter. However, the researchers assume that the remaining 90 percent of the nanoparticles also consist of nanoplastics.