Two Dartmouth medical research analysts recently commented on a new study that links a chemical used in plastic water bottles -- including discontinued Nalgene models -- to adverse health effects in people. The analysts said the study raises questions, but offers no answers as to whether the chemical is harmful.
The study, published in last month's Journal of the American Medical Association, links the chemical known as BPA, 2,2-bis(4-hydroxyphenyl)propane, to possible health risks for heart disease and diabetes. Researchers examined urine samples taken from 1,455 American men and women between the ages of 18 and 74. Adults whose urine contained the highest levels of BPA were 2.9 times more likely to have heart disease and 2.4 times more likely to have diabetes than those subjects with the lowest levels of BPA.
The scientific study was published a month after the Food and Drug Administration released an internal report concluding that BPA exposure is not harmful enough to warrant federal action.
At Dartmouth, students expressed concern over the possibility that their plastic water bottles are leaking toxic chemicals.
Brian Bowden, coordinator for alcohol and other drug education programs for College Health Services, said the College decided to stop distributing Nalgene plastic water bottles after hearing about the potential health risks associated with BPA, switching to non-plastic Camelbak water bottles last year.
Chemistry professor Robert Grubbs explained that BPA is commonly found in plastic water bottles because it is easy to mass-produce.
"The keys to why it's so prevalent are that it's relatively easy to make on a very large scale and it has two phenol groups with a specific type of reactivity," Grubbs said. "These phenol groups allow you to string it together with other molecules in long polymer chains to form polycarbonates, which you see a lot in water bottles, and many types of epoxy resins. Probably the chief area that's still of interest in trying to minimize [BPA] intake in people's diets is the use of epoxy in linings of aluminum cans or other places where you don't want the contents of the container to leach out the metal."
In recent years, a growing number of researchers have addressed the potential health risks of BPA. In January 2008, the Environmental Health Perspectives journal published a study showing that BPA acts as an endocrine disrupter, interfering with hormonal processes such as reproduction and development, even in very low doses.
Frederick vom Saal, a professor of biological sciences at the University of Missouri, and John Peterson Myers, chief scientist at the non-profit group Environmental Health Sciences, said their September study was the first to examine possible BPA effects in human subjects and the first to suggest a link to human heart disease. Vom Saal co-authored a 2005 study assessing the effects of low doses of the chemical in rats.
While the European Union has said that products containing BPA are safe, the Canadian government has proposed banning the sale of baby bottles that contain the chemical. The Health Canada organization cited vom Saal's study when it officially designated the chemical as "toxic" to human health" in April 2008. Shortly after the organization's announcement, Nalge Nunc International, thte producer of Nalgene water bottles, ceased the production of all plastic water bottles that contained BPA.
A woman in California filed a consumer class-action lawsuit against Nalge Nunc International in April 2008, claiming that the company dismissed the possibility that their products contained BPA and could potentially affect customers' health. The lawsuit came a week after the U.S. government's National Toxicology program expressed "some concern" about exposure and its possible effects on the brains of fetuses, infants and children.
