Linus the Turbonerd sends in the bulletin that BPA, a toxic chemical used in the production of polycarbonate, the plastic composing hard, clear water bottles, has been found to leach out of such containers, directly into the water that their users consume. "In addition to polycarbonate bottles, which are refillable and a popular container among students, campers and others and are also used as baby bottles, BPA is also found in dentistry composites and sealants and in the lining of aluminum food and beverage cans. ... '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. This would be of concern since infants may be particularly susceptible to BPA's endocrine-disrupting potential,' said Karin B. Michels, associate professor of epidemiology at HSPH and Harvard Medical School and senior author of the study."