By Lyndsey Layton
Washington Post Staff Writer
Thursday, September 4, 2008
Researchers at the Yale School of Medicine have linked a chemical found in everyday plastics to problems with brain function and mood disorders in monkeys -- the first time the chemical has been connected to health problems in primates.
The study is the latest in an accumulation of research that has raises concerns about bisphenol A, or BPA, a compound that gives a shatterproof quality to polycarbonate plastic and has been found to leach from plastic into food and water.
The Yale study comes as federal toxicologists yesterday reaffirmed an earlier draft report finding that there is "some concern" that bisphenol A can cause developmental problems in the brain and hormonal systems of infants and children.
"There remains considerable uncertainty whether the changes seen in the animal studies are directly applicable to humans, and whether they would result in clear adverse health effects," John R. Bucher, associate director of the National Toxicology Program, said in a statement. "But we have concluded that the possibility that BPA may affect human development cannot be dismissed."
In a study published in the Proceedings of the National Academy of Sciences, the Yale team exposed monkeys to levels of bisphenol A deemed safe for humans by the Environmental Protection Agency and found that the chemical interfered with brain cell connections vital to memory, learning and mood.
"Our findings suggest that exposure to low-dose BPA may have widespread effects on brain structure and function," the authors wrote. In contrast to earlier research on rodents, the Yale researchers studied monkeys to better approximate the way BPA might affect humans.
"Our goal was to more closely mimic the slow and continuous conditions under which humans would normally be exposed to BPA," said study author Csaba Leranth, a Yale professor of obstetrics, gynecology and reproductive sciences and of neurobiology.
BPA, in commercial use since the 1950s, is found in a wide variety of everyday items, including sports bottles, baby bottles, food containers and compact discs. One recent federal study estimated that the chemical is found in the urine of 93 percent of the population.
The American Chemistry Council, a trade group, maintained yesterday that "there is no direct evidence that exposure to bisphenol A adversely affects human reproduction or development."
The National Toxicology Program, part of the National Institutes of Health, has no power to regulate BPA, but its findings are used by other federal agencies such as the Food and Drug Administration and the EPA, which set safe exposure limits for chemicals.
The FDA plays a critical regulatory role because it regulates the compound's use in plastic food containers, bottles, tableware and the plastic linings of canned foods.
The agency last month issued a draft report that declared BPA safe for use in food packaging and bottles, based largely on the strength of two studies, both funded by industry.
"Unfortunately the regulatory agency charged with protecting the public health continues to rely on industry-based research to arrive at its conclusions, rather than examining the totality of scientific evidence," Rep. John D. Dingell (D-Mich.), chairman of the House Energy and Commerce Committee, said in a statement yesterday. His committee is investigating the FDA's handling of BPA.
U.S. manufacturers make about 7 billion pounds of BPA annually. A ban would affect thousands of businesses and perhaps billions of dollars in profit for its largest manufacturers.
Canada has said it intends to ban the use of BPA in baby bottles, and state and federal lawmakers have proposed a variety of BPA bans. Sen. Charles E. Schumer (D-N.Y.) is sponsoring a bill to prohibit BPA from children's products, while Rep. Edward J. Markey (D-Mass.) wants to bar it from all food and drink packaging.
"The FDA's assurances of BPA's safety are out of step with mounting scientific evidence to the contrary," Markey said yesterday. "For the sake of the health of every man, woman and child in America, we should ban BPA in food and beverage containers, especially because there are alternatives already available."
Several major retailers, including Wal-Mart and Toys R Us, have pledged to drop BPA products next year while some makers of baby bottles and sports bottles have switched to BPA-free plastic.