Several hundred chemicals have been found in tap water stored in reusable plastic bottles.
- The bottles used were gourds, reusable, made of plastic.
- Going through the dishwasher increases the number of residues in the water.
- Researchers do not know if these substances are harmful to human health.
What happens in a bottle of water in 24 hours? Lots of things when made of reusable plastic. Two scientists from the University of Copenhagen have observed the composition of water when it is stored in these plastic containers. The results, published in Journal of Hazardous Materialssurprised them. “We were surprised by the large amount of chemicals we found in the bottled water after 24 hours, explains Jan H. Christensen, co-author and professor of chemistry. There were hundreds of substances in the water – including substances never before found in plastic, as well as potentially harmful substances.you.”
Imitate the ordinary use of reusable bottles
The scientists used three types of water bottles for their study, all sold in Danish stores. Two of the bottles are made of biodegradable plastic, according to the manufacturer. The researchers tested new gourds, others very used. The aim was to imitate the way they are generally used. “People often drink water that has been stored in bottles for several hours”, say the authors. Regular tap water was stored in new and used bottles for 24 hours, before and after going through the dishwasher, then for some, rinsed thoroughly with tap water afterwards.
More than 400 substances detected in water
Jan H. Christensen and fellow researcher Selina Tisler detected more than 400 different substances from the plastic of the bottle and more than 3,500 substances derived from dishwashing soap. Many of these substances are unknown and researchers have yet to identify them. But some are of particular concern to them, in particular photoinitiators: these are toxic substances known to have potentially harmful effects on the health of organisms. The scientists also detected a variety of fabric softeners, antioxidants and mold release agents used in plastic manufacturing, as well as diethyltoluamide (DEET), the active substance in mosquito repellent sprays. “What is released the most after machine washing are soapy substances, says Selina Tisler. (…) The most toxic substances we identified actually came after the bottle was in the dishwasher.“ According to her, it is probably linked to the fact that going through the dishwasher wears out the plastic.
Water dangerous to health?
For now, scientists do not know if the water contained in these bottles is dangerous to health. “Just because these substances are in the water does not mean that the water is toxic and affects us humans. says Selina Tisler. But the problem is that we just don’t know. In principle, it is not recommended to drink residues of soap or other chemicals. Toxicological assessments are underway to understand the effects of these residues on human health. When in doubt, his colleague, Jan H. Christensen, says he will now choose glass or stainless steel bottles.
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