Polycarbonate Disposable Water Bottles Found to Release BPA

A new study has found that polycarbonate containers leach the chemical bisphenol A (BPA), which has been linked with cardiovascular disease, diabetes, and possible reproductive development impairment, into the liquid stored in them.

Researchers at the Harvard School of Public Health (HSPH, Boston, MA, USA) followed 77 students that participated in the study who were given two polycarbonate bottles, and asked to drink all cold beverages from the bottles during one week. The students were first asked to undergo a seven-day "washout" phase, in which they drank all cold beverages from stainless steel bottles in order to minimize BPA exposure. Additionally, the students did not wash their bottles in dishwashers or put hot liquids in them, as heating has already been shown to increase the leaching of BPA from polycarbonate. The results showed that the urinary concentrations of BPA had increased by 69% after drinking from the polycarbonate bottles in a normal way. While previous studies had found that BPA could be transferred from polycarbonate bottles into their contents, this study shows a corresponding increase in urinary BPA concentrations in humans. The study was published online in the May 12, 2009, issue of Environmental Health Perspectives.

"We found that drinking cold liquids from polycarbonate bottles for just one week increased urinary BPA levels by more than two-thirds. If you heat those bottles, as is the case with baby bottles, we would expect the levels to be considerably higher," said lead author Karin Michels, Ph.D., and associate professor of epidemiology at HSPH and Harvard Medical School. "This would be of concern since infants may be particularly susceptible to BPA's endocrine-disrupting potential."

BPA is an organic compound with two phenol functional groups, and is a building block of several important plastics and plastic additives. With an annual production of 2-3 million metric tons, it is an important monomer in the production of polycarbonate. BPA is also found in dentistry composites and sealants and in the lining of aluminum food and beverage cans. In October 2008, the U.S. Food and Drug Administration (FDA) stated that "consumers should know that, based on all available evidence, the present consensus among regulatory agencies in the United States, Canada, Europe, and Japan is that current levels of exposure to BPA through food packaging do not pose an immediate health risk to the general population, including infants and babies."

Consumers can tell if a bottle or vessel contains BPA by turning it over and checking the recycling triangle stamped on it. A No. 7 inside the triangle means it could contain BPA.

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Harvard School of Public Health