In the office, on a trip or at school, you should never give up drinking and staying hydrated. In fact, dehydration immediately slows down cognitive function, lowers attention, worsens mood and immediately makes you feel more tired and exhausted, as well as having even more serious consequences if you do not take fluids (Zhang et al, Int J Environ Res Public Health., 2019). The problem, however, is that you often don't know in which container to put the water to take with you. On the market there are different types of water bottles, practical, reusable and also environmentally friendly. But are they also health friendly? Let's try to understand this by analyzing the different materials with which we can find the bottles and their effects, focusing on the possible release of toxic metals and bisphenol A, an endocrine disruptor that may alter the hormone balance.
A recent study performed by a team of scientists from the La Sapienza University of Rome carried out a series of tests on the water contained in bottles of different materials (Astolfi et al, Separations, 2021). After a month in which the researchers filled and emptied the water bottles daily, just as is commonly done in everyday life, the quality of the water was analyzed. What emerged was that aluminum and stainless steel water bottles, more than other materials, released toxic metals such as lead, nickel, cobalt and antimony. These metals were below the legal limits but it must be emphasized that this contribution, which in the case of a bottle used every day becomes constant, is added to the metals contained in the water that we already consume with the risk of exceeding the quantities. In addition, if the inner lining of an aluminum bottle is an epoxy resin, bisphenol A is likely to be released as well (Cooper et al, Chemosphere, 2012).
Stainless steel water bottles
The study mentioned in the previous paragraph also analyzed stainless steel water bottles. Also in this case, the water bottles were found, together with the aluminum bottles, to release a greater amount of toxic metals into the water (Astolfi et al, Separations, 2021). However, stainless steel water bottles have been shown not to release bisphenol A (Cooper et al, Chemosphere, 2012).
The polycarbonate plastic bottles, or PC, release to the water bisphenol A, especially if the liquid temperature is high or if they are left in a hot place (Cooper et al, Chemosphere, 2012). On the other hand, the latest generation copolyester bottles do not release bisphenol A (Cooper et al, Chemosphere, 2012). The PET bottles are also interesting. In general, as the study by the La Sapienza University testifies, all the bottles analyzed, including PET, release toxic metals. However, plastic materials release significantly less of these substances than metal water bottles. This study is also confirmed thanks to another research, which observed that the amount of antimony, metal with a possible carcinogenic action (IARC), in the water contained in PET bottles is very low, around 1% of the threshold considered safe by WHO (Welle et al, Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2011). Finally, PET has not been shown to release bisphenol A (Astolfi et al, Separations, 2021).
Glass bottles were found to be the best, the most efficient and the safest in terms of substances released to the water (Astolfi et al, Separations, 2021).
Bottles, some advice
The general advice, for all bottles of any material, is to change the water often. This is especially true for aluminum bottles. In fact, water can extract aluminum and therefore this liquid should never be stored for more than 24 hours in a container of this type, better clearly if it is changed more frequently. The advice is always to make sure that the origin and the manufacturer are certified on the bottle and that the interior is as smooth as possible, without welding. Avoid storing soft drinks and sparkling water (Source, interview with Professor Matteo Vitali, La Sapienza University and head of the research team that published Astolfi et al, Separations, 2021).