To conserve water, it is better to choose glass bottles ... In fact, do you know that strange smell that water often takes after being stored for a while in a plastic bottle? The reason for this seems to be the hundreds, if not thousands, of substances that pass from plastic to water, some of these also unknown and many considered toxic. These are the results of a very recent study that will be published next month in the Journal of Hazardous Materials by a Danish team (Tisler et al, Journal of Hazardous Materials, March 2022).
Bottles, a blessing and a curse
Bottles are an almost indispensable tool for athletes, students or for those who spend a lot of time away from home, for work or leisure. Water bottles are also an environmentally friendly choice, avoiding a lot of disposable bottles. But for bottles to be a good choice, they must also be harmless to health. This is why more and more studies are focusing on the quality of water after it has been stored in water bottles of various materials. However, little is known about what happens to the water in plastic bottles, especially after they have been washed in the dishwasher, a gesture that we all perform, especially when the bottle is new.
Plastic water bottles release hundreds of substances
To fill this gap, the Danish researchers conducted a study on reusable plastic bottles, new, already used for a year and after being washed in the dishwasher. The bottles were filled with purified water free of contaminants and, after 24 hours, the water was analyzed. What emerged surprised researchers who did not expect to find more than 400 substances in water, some of which have never been found in plastic until now. After washing in the dishwasher, the substances found in the water have even risen to several thousand. Many of these substances were also found to be unknown. Various toxic substances have also been isolated, such as carcinogens and endocrine disruptors, which can alter the hormonal balance. Not only that, substances used to soften plastic and also substances that have nothing to do with plastic, such as Diethyltoluamide, have been found in the water. This substance is found as an active ingredient in mosquito repellent sprays. It seems that Diethyltoluamide, a substance that can be toxic if ingested, can be formed from other substances used in the manufacture of plastic bottles, such as laurolactam. It may seem strange that the substances contained in the water have increased after washing in the dishwasher. This actually has an explanation. In fact, washing in the dishwasher, which is generally carried out on new bottles, can wear down the plastic and increase the risk of releasing substances. However, even a simple rinsing of new bottles did not eliminate the release of substances that have been estimated to be in the order of several hundred.
However, as pointed out by the same authors of the study, the fact of having found hundreds if not thousands of substances in the water, many of which are also unknown, does not mean that the water contained in the plastic bottles is toxic for humans. But this is the point, no one knows. In fact, it is not yet known whether or not the concentrations of toxic substances are sufficient to cause damage and the effects of almost 70% of the substances found in the water, many of which still to be identified, are not known. Science needs to continue its course, in the meantime, however, it is possible to opt for alternatives to plastic bottles, such as glass bottles. And in any case avoid washing plastic bottles in the dishwasher, if you have them at home.