In a study published in Environmental Health Perspectives, Harvard School of Public Health researchers found that participants who drank for a week from polycarbonate bottles showed a two-thirds increase in their urine of the chemical bisphenol A (BPA).
The study, according to its authors, is the first to show that drinking from polycarbonate bottles increases the level of urinary BPA. The study participants—77 Harvard college students—began by drinking all cold beverages for seven days from stainless steel bottles in order to minimize BPA exposure. The participants provided urine samples during the seven-day period.
They were then given two polycarbonate bottles and asked to drink all cold beverages from the bottles during the next week. Urine samples also were provided during that time. The results showed that the participants’ urinary BPA concentrations increased 69% after drinking from the polycarbonate bottles. In this study, the students did not wash their bottles in dishwashers or put hot liquids in them.
The researchers noted that they would expect the levels to be even higher if the bottles were heated, as in the case of baby bottles.