2024-01-12 09:59:13
by Anna Fregonara
They are smaller than known microplastics and have been measured in three US brands of bottled water. The average was between 110 thousand and 370 thousand particles per liter. What effects on health?
A study from a few years ago found that each of us could consume the equivalent by weight of a credit card of small plastic particles every week. These microparticles are known as microplastics and are formed when plastic breaks into progressively smaller pieces. Precisely because of their tiny size they can be absorbed by humans, animals and the environment, with potential effects on health and the ecosystem.
Le nanoplastiche
However, there is a world of even smaller particles that are still little known due to the lack of effective analytical techniques: this is the world made up of nanoplastics, “daughters” of microplastics that have broken down further. A few days ago, a group of researchers, si legge su Proceedings of the National Academy of Sciences
tried to count and identify those contained in three popular brands of bottled water sold in the United States (he did not want to specify which ones) thanks to the development of an optical imaging technique for the rapid analysis of nanoplastics with even greater sensitivity and specificity accurate.
Comment on the study
The researchers identified 105 particles per liter of bottled water, of which approximately 90% are nanoplastics. «The strength of this study is not on the data on the presence of nanoplastics in drinking water, the results of which are consistent with the dozens of investigations of the last 10 years, but on the new technology used to measure the smallest particles more precisely and fast”, explains Enrico Davoli, head of the Mass Spectrometry Laboratory at the Environment and Health department of the Mario Negri Pharmacological Research Institute in Milan. «The weak aspect of the investigation concerns the sampling: the number of bottles and the detail of their material is not clear, it is not known what the corks were made of, how many bottles were new or old, how many had been exposed to the sun . These aspects are important before drawing conclusions on the nanoplastics present.”
One hundred times smaller than a hair
Microplastics are defined as fragments ranging from 5 millimeters up to 1 micrometer, or 1 millionth of a meter. Nanoplastics, which are particles smaller than 1 micrometer, are measured in billionths of a meter. «To give you an idea, nanoplastics are a hundred times smaller than the diameter of a hair», specifies the researcher. It is believed that, precisely because of their smaller size compared to microplastics, they are favored to enter the human body. What does this mean for our health?
Hypothesis of adverse health effects
«It has been shown that the larger microplastics enter and exit the digestive tract, in our respiratory tree they stop in the highest passages, at the level of the nose or just below. Nanoplastics, on the other hand, travel down the respiratory tree until they reach, depending on their size, the alveoli. In the intestine they are absorbed and enter the bloodstream. It is not surprising, therefore, when we read that they have been found, for example, in the placenta. It has been seen that they can generate a state of inflammation, but we have no evidence on what happens afterwards. All experimental studies focused on tumors, for example, have given negative results. Furthermore, it has been seen that they interact with proteins and therefore can alter the system of transmission of information from organ to organ which is powered by some hormones which are proteins. There are many variables at play, but there are still few known aspects. There are hypotheses on the possible toxicological effects that change depending on the type of plastic, the shape, the size and depending on how dirty the nanoplastics are, i.e. what they “carry” on their surface”.
What do they do in our body?
«The great challenge is to understand what nanoplastics do in our body once we inhale or eat them: unfortunately there is no evidence to be able to define our real exposure to nanoplastics or to understand whether their interference with proteins can influence, for example, on neurodegenerative diseases such as Alzheimer’s, Parkinson’s, Huntington’s, Amyotrophic Lateral Sclerosis. For this reason, a necessary first step to take for research to shed light is to develop standard measurement methods at a global level. This would help to understand how many nanoplastics there are around and, consequently, we could understand the exposure data, i.e. how many a person inhales or ingests.”
Plastic data
“Global plastic production is approaching 400 million tons per year,” said study co-author Beizhan Yan, an environmental chemist at Columbia University’s Lamont-Doherty Earth Observatory. «More than 30 million tonnes are thrown into water or on land every year and many products made from plastic, including synthetic fabrics, shed particles while still in use. Unlike natural organic matter, most plastics do not break down, but divide and redivide into increasingly smaller particles of the same chemical composition.”
What we can do: there is the 3 «R» rule
«To safeguard the environment there is the 3 “R” rule: reuse, reduce, recycle», concludes Davoli. «The fourth “R” is that of reject and that is what we can commit ourselves to. As little as possible buy objects or foods wrapped in plastic. The recycling of this material is important for reducing pollution and it is a good idea to encourage the use of recycled materials. Plastic is an Italian invention of the Nobel Prize winner for chemistry Giulio Natta and its strength lies in being a light, inexpensive and long-lasting material: from here we can understand the absurdity of single-use. It is not so much the invention of plastic itself that causes harm, think of its important use in biomedical instruments, but the abuse that is made of it.”
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January 12, 2024 (modified January 12, 2024 | 08:58)
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