By now we are all clear that drinking water helps maintain health. But when we do so, in addition to the fluid, we may be ingesting different natural and artificial compounds and particles that are not so healthy if they exceed a certain concentration. One of them is plastics.

Plastics were manufactured for the first time in the 20th century to meet the needs of society at the time and thanks to their extraordinary characteristics they have remained among us, offering us multiple solutions.

Some of the properties that make them perfect materials to be used in different areas of society are their great diversity of shapes and sizes, their resistance, their impermeability, their low production cost and their great durability. All of this allows us to manufacture an endless number of products with different uses that are widely used in our daily lives.

In recent years, there has been a notable increase in the production of plastic products, which has resulted in the generation of approximately 400 million tons of this material per year worldwide. This high figure and its great durability are the cause of great negative impacts on the environment and living beings, since not 100% of the plastic waste produced is recycled.

Once these plastics enter the natural environment, they undergo a degradation process, becoming increasingly smaller particles, which gives rise to what we know as microplastics.

These microplastics are characterized by having a size that varies between 1 ?m and 5 mm. They have already been found in all the environments analyzed – atmosphere, oceans, soil… – and even in the food and water we drink.

Members of the Enviroplanet plastics research network, made up of several Spanish research groups specialized in plastic pollution, last year we published a study in the journal Water Research on the presence of microplastics and artificial non-plastic particles in the drinking water of eight Spanish cities.

This year, the same Enviroplanet researchers, thanks to an agreement signed by the Autonomous University of Madrid, in collaboration with the Organization of Consumers and Users (OCU), have published a study in the journal Scientific Reports on the presence of microplastics in the bottled water.

For this work, we analyzed bottles from five of the main bottled water brands, which together represent 40% of the still bottled water market in Spain. For each brand of water, a total of 45 liters contained in 1.5-liter plastic (PET) bottles were processed.

The final results have allowed us to compare the concentration of microplastics and non-plastic artificial materials in bottled water with that found in tap water, with the aim of determining if there are significant differences between both sources.

In our study we have mainly identified polyester fragments of transparent and white tones, which coincides with the typical composition of water bottles, in addition to cellulose fibers of various colors.

In tap water, however, we detect a greater diversity of polymers, including polyesters, polyamides, acrylic polymers and polyolefins. These commonly used materials come from a variety of sources, from synthetic textiles to food packaging, paints or household appliances.

It is important to note that, although polyesters, of which polyethylene terephthalate or PET are a part, are present in both samples, their abundance is lower in tap water compared to bottled water.

The average concentration of microplastic particles (MP) in bottled water was about 0.7 MP/L, while the concentration of non-plastic particles of artificial origin (PANP) was about 1.70 PANP/L. These data show a greater presence of microplastics in bottled water compared to tap water, where the average concentration was 0.0125 MP/L and 0.0322 PANP/L.

Although the concentration of microplastics in bottled water is significantly higher than in tap water, it is very unlikely that plastic ingested this way will cause adverse effects in humans because the amount ingested by total weight is negligible. However, there are no studies to date showing whether these concentrations can cause harm in humans.

However, the precautionary principle requires us to be cautious about the risk of plastic contaminants in drinking water. It is essential that governments and regulatory bodies support studies to develop informed policies on contaminants in food and water, in addition to encouraging the use of the cleanest sources possible, in this case tap water, cost-effective and environmentally friendly. environment and reduces the amount of plastic waste generated and, therefore, the associated carbon footprint.

This article was originally published on The Conversation. Virginia Gálvez Blanca is a PhD student in Hydrology and Water Resources Management at the University of Alcalá; Carlos Edo is a Postdoctoral researcher at the University of Alcalá; Francisca Fernández Piñas is

Professor of Biology at the Autonomous University of Madrid;  Miguel González-Pleiter is a researcher in Ecotoxicology at the Autonomous University of Madrid; Roberto Rosal is Professor of Chemical Engineering at the University of Alcalá