Microplastics in water: they are eliminated by boiling. The pros and cons of a system that could save us from pollution

It could be as simple as making a cup of tea or coffee clean drinking water from the tapboth sweet and hard, from micro and nano plasticsthose microparticles that form when plastic breaks into progressively smaller pieces.

Where am I

To give you an idea, nano plastics are one hundred times smaller than the diameter of a hair. Precisely because of their tiny size, micro and nano plastics can be inhaled or ingested by humans and by animals and absorbed by the environment with potential effects on health and the ecosystem which are being studied.
For example, they have been found deposited in the depths of the sea and on Mount Everest, they have become stuck in volcanic rocks, in sea birds, they have even fallen into the fresh snow of Antarctica. And they are in our bodies: in the placentaIn the Heartwere ultimately found in blood (we wrote about it HERE).

In water

The problem is so widespread that some scientists are using them to try to define the Anthropocene, a term coined to indicate the current geological era in which the terrestrial environment, that is, the set of physical, chemical and biological characteristics in which it takes place and life evolves, it is modified on both a local and global scale by man and his activities. Also bottled water, scientists found earlier this year, on average it contained between 110,000 and 370,000 particles per liter.

A hand from limestone?

Now Eddy Zeng of Jinan University in China and his colleagues, we read in Environmental Science & Technology Letterscollected samples of hard tap water in Guangzhou and spiked them with varying amounts of micro- and nanoplastics.
The samples have been made boil for five minutes and let it cool. Boiling water, rich in minerals, naturally forms scale limestone (calcium carbonate) which trap plastic particles. According to Zeng, the removal of these encrustations would allow the water to be decontaminated by plastic fragments while it could be sufficient filter it to clean it from the remaining encrustations that float. In the tests, the benefit was more pronounced in harder waters: in a sample containing 300 milligrams of limestone per liter of water, at least 80% of the micro and nano plastics were removed after boiling, while in the soft water samples , those with less than 60 milligrams of limestone per liter, boiling removed about 25% of microplastics. «We estimated that the intake of micro and nanoparticles through the consumption of boiled water was two to five times lower than tap water on a daily basis», Zeng told New Scientist.

Condominium system?

The boiling idea seems to work, at least for the three types of plastic investigated by the researchers: polystyrene, polyethylene and polypropylene.

Does this mean that if you fill a kettle with tap water at home and boil it, you clean it up? «From what emerges from these first data it seems like this the more calcareous the water the better. Flocculation technologies, such as this one, i.e. those processes that facilitate the aggregation of small particles in a liquid or in a solution into larger agglomerates known as flocs, are giving many interesting ideas for tackling this type of pollution also because I definitely am more practicable than filtrations“, explains Enrico Davoli, head of the Mass Spectrometry Laboratory at the Environment and Health department of the Mario Negri Pharmacological Research Institute in Milan. «In theory, boiling could be a system achievable at a condominium level, but today it is too early to consider it. The evidence collected by researchers still needs to be better “parametrized”: how long, how much limescale and so on. The cost is relative, probably optimizable and in any case must be evaluated as a cost/benefit ratio. From an energy point of view, however, it is expensive. Drinking boiled water also has other advantages: it is sanitized thanks to the elimination, for example, of bacteria and parasites and thanks to the removal of traces of heavy metals, but potential micronutrients could be lost. However, talking about it is a way to raise people’s awareness of these problems.”