Researchers and scientists from the University of Cincinnati College of Medicine conducted a study, “Assessment of Bisphenol A Released from Reusable Plastic, Aluminium and Stainless Steel Water Bottles,” suggesting that certain metal bottles can leach the hormone-disrupting chemical bisphenol A (BPA).
According to the study, published in the journal Chemosphere, aluminum bottles with a resin liner can still leak the potentially harmful chemical into drinking water. While the metal drinkware itself does not contain any BPA, the epoxy-resin lining in some bottles can potentially leak more BPA than the liner-free polycarbonate alternatives.
The amount of the chemical found in drinking water increased was higher in polycarbonate bottles than in the aluminum variety at room temperature, but as the temperature was raised, the epoxy-lined metal bottles released more BPA than the plastics. When filled with boiling water, the lined steel bottles released four times more than the polycarbonate bottles.
BPA, which has been shown to disrupt estrogen levels in animals, is commonly used to make shatterproof plastics and polycarbonates. It is regularly used to create the lining in aluminum cans used for soft drinks and canned vegetables, as well as some drinkware liners.
The study suggested that BPA-free plastic bottles, and stainless steel bottles that do not have a liner, do not release any BPA and are safe to use. “The results from this study demonstrate that when used according to manufacturers’ recommendations, reusable water bottles constructed from ‘BPA-free’ alternative materials are suitable for consumption of beverages free of BPA contamination,” the study concluded.