Some researchers analyzed 280 samples of bottled water. Only one of the brands was microplastics free

Better flavor and smell and health reasons. Those are the two main reasons why people drink bottled water, according to A study of the Autonomous University of Barcelona. Spain is, in fact, The third European country that consumes more bottled water (up to 107 liters per inhabitant). That clashes with one thing: that bottled water is not only Much more expensive than tap waterbut now we know that it also has micro and nanoplastic in amounts much greater than those estimated.

The original study. Some researchers from Columbia University They analyzed Three popular bottled water marks in the United States (whose names names have not transcended) in search of micro and nanoplastic. To do this, they used a new technique called Raman stimulated dispersion microscopy Based on probe samples with two tuned simultaneous lasers to resonate specific molecules.

Analyzing seven common plastics, the researchers developed an algorithm to interpret the results. According to Wei Min, co-inventor of the technique and co-author of the study that concerns us, “one thing is to detect and another to know what you are detecting.”

The findings. On average, this study discovered that a liter of bottled water contains 240,000 detectable plastic fragments, between ten and 100 times more than previous estimates. Specifically, the researchers claim that they found between 110,000 and 370,000 plastic fragments in each liter, of which 90% were nanoplastic. In that sense, it is important to remember the difference between micro and nanoplastic:

• Microplastics: those whose size varies between 100 nanometers and five millimeters.
• Nanoplastic: those whose size is equal to or less than 100 nanometers.

The most frequent plastics. To anyone’s surprise, one of the most common plastics was the Terephthalate polypropylene, better known as PET. It is the material of which many bottles are made. “It is probably introduced into the water when pieces are detached when the bottle is squeezed or exposed to heat,” says the researchers, who cite another study that suggests that they can also detach themselves when the cap repeatedly opens and closes.

Usual. And although the presence of PET is common, this plastic is overcome by the polyamide, a type of nylon that “probably comes from the plastic filters used to supposedly purify the water before bottling it,” says Beizhan Yan, a researcher of the study. Other common plastics found by the researchers were polystyrene, polyvinyl chloride and methyl polymetacrylate.

And the rest? The technique used contemplates the seven most common plastics, but there are many other plastics. According to exposes Columbia University, “the seven types of plastic that researchers sought only represented about 10% of all the nanoparticles found in the samples; They have no idea what the rest are. If all are nanoplastic, they could be dozens of millions per liter. ”

And what about those sold in Spain? That’s what he wanted to find out A study by CSIC and the Global Health Institute of Barcelona. They have developed a technique To quantify particles of between 0.7 and 20 micrometers, as well as the chemical additives released to the water and, for this study, analyzed 280 samples of 20 trademarks of commercial water. Only one of the brands did not contain microplastics, but all, the 280 samples, contained plastic additives.

More specifically. The result is that, on average, a liter of water contains 359 nanograms of micro and nanoplastic, an amount comparable to that obtained in the tap water found in a previous study made by the same group. “The main difference we find is the type of polymer: in tap water we find more polyethylene and polypropylene while in bottled water we have mostly detected polypropylene terephthalate (PET), although also polyethylene,” said Cristina Villanueva, a researcher of the Isglobal and Author of the study.

Quite microplastic. Considering that we drink two liters of water a day, the authors estimate “an intake of 262 micrograms of plastic particles per year.” With regard to additives, 28 plastic additives, mostly stabilizers and plasticizers have been detected. According to the researchers, “our toxicity study showed that three types of plasticizers had a higher risk to human health and, therefore, should be considered in risk analysis for consumers.”

Images | Jonathan Chng in Unspash

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*An earlier version of this article was published in February 2024