18. CHEMICALS: U.S. EPA study fuels controversy, questions harm of BPA (04/13/2010)

Sara Goodman, E&E reporter

The results of a three-year U.S. EPA investigation probing the effects bisphenol A, or BPA, may have on the body's endocrine sex hormones have called into question whether the chemical poses a serious health risk to humans.

The research, carried out by EPA, suggests that rats remained unharmed when fed doses of BPA 4,000 times higher than the maximum exposure experienced by humans.

But the work, published in the latest issue of Toxicological Sciences, was immediately denounced as "flawed" by some endocrine experts who believe the chemical is dangerous in low doses.

Frederick vom Saal of the University of Missouri is one prominent voice blasting the findings of EPA's Earl Gray and his colleagues. Vom Saal said the study was inherently flawed because it used a strain of rats that were not sensitive to low doses of a female sex hormone that BPA is said to mimic.

"By failing to establish the sensitivity of the animal model to the class of chemical being tested, the authors violated U.S. National Toxicology Programme recommendations for low-dose studies of endocrine-disrupting chemicals," vom Saal wrote in a letter to the publication.

Meanwhile one of Britain's leading specialists in endocrine-disrupting chemicals in the environment, Richard Sharpe, said Gray's study was one of the best he had seen looking at the highly controversial question of a link between BPA and endocrine disruption.

"The results [of the study] are unequivocal and robust and are based on a valid and rational scientific foundation," Sharpe said (Steve Connor, London Independent, April 13). -- DFM