One liter of bottled water can contain up to 370 thousand particles of degraded plastic, 90% in the form of nanoplastics, microscopic fragments that are difficult to identify both in number and type of plastic of origin. Their precise detection for the first time has now been achieved by a team of Chinese and US researchers and described in a study (Qian, Gao et al., 2024) published in Proceedings of the National Academy of Sciences (PNAS). (1)
Microplastics and nanoplastics
Microplastics are now considered ubiquitous. They have been detected in bottled water, fruits and vegetables, even human placentas and lungs. (2,3,4,5)
The dimension of plastic fragments defined as ‘micro’ range from 5 millimeters up to 1 micrometre, i.e. 1 millionth of a metre. To have a reasoning parameter, consider that a human hair is approximately 70 micrometers wide.
Nanoplastics are even smaller. They have dimensions smaller than 1 micrometer and are therefore measured in billionths of a meter.
An unstoppable ‘invasion’
The nanometric dimension heightens fears about the impact of these particles on human health. Nanoplastics, in fact, manage to pass through the intestine and lungs into the bloodstream and from there they can reach the organs, including the heart and brain. They can penetrate cells and cross the placenta to reach the fetus.
The possible biological causes of this ‘invasion’ are still being studied. The evidence that is gradually emerging is not very reassuring. An Italian study (Iannilli, Passatore et al., 2023) recently found that microplastics dispersed in the environment cause genetic damage (genotoxicity) to freshwater shrimp (6).
The count of nanoplastics in bottled water
The authors of the current study have for the first time counted and identified the nature of nanoparticles contained in three (undisclosed) brands of mineral water using a technique called ‘hyperspectral stimulated Raman scattering (SRS) microscopy’.
This approach was focused on seven most common types of plastic and fragments up to 100 nanometers in size.
Three known plastics and many more unknown
The outcome of the analysis highlighted that
– 110.000 to 370.000 plastic particles were measured in one liter of mineral water,
– 90% of the particles identified in the analysed water are nanoplastics, the rest microplastics,
– polyamide, a type of nylon also used to filter water before bottling, is the most frequently detected plastic,
– PET (polyethylene terephthalate) is the second most detected plastic. This material is the most used to package water,
– polystyrene, polyvinyl chloride and polymethyl methacrylate, all used in various industrial processes, are other plastic materials found in large quantities.
A disturbing aspect is that the seven types of plastic the researchers looked for represent only about 10% of all the nanoparticles found in the samples. What the remaining 90% comes from is unknown. If they were other microscopic fragments of plastic there would be contamination in the order of tens of millions of nanoparticles per liter of water.
Marta Strinati
Footnotes
(1) Qian N, Gao X, Lang X, Deng H, Bratu TM, Chen Q, Stapleton P, Yan B, Min W. Rapid single-particle chemical imaging of nanoplastics by SRS microscopy. Proc Natl Acad Sci U S A. 2024 Jan 16;121(3):e2300582121. doi: 10.1073/pnas.2300582121. Epub 2024 Jan 8. PMID: 38190543. https://doi.org/10.1073/pnas.2300582121
(2) Marta Strinati. Microplastics in mineral water. The French report. GIFT (Great Italian Food Trade).
(3) Marta Strinati. Microplastics in fruit and vegetables. The Italian study. GIFT (Great Italian Food Trade).
(4) Marta Strinati. Microplastics in the human placenta. The discovery of Italian researchers. GIFT (Great Italian Food Trade).
(5) Marta Strinati, Dario Dongo. Microplastics in our lungs too. The British study. GIFT (Great Italian Food Trade).
(6) Marta Strinati. Microplastics, new evidence of genotoxicity on freshwater shrimp. GIFT (Great Italian Food Trade).
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
