The report, which was published online Sept. 1 by Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society, revealed higher levels of flame retardants in the foods here than similar market studies from other countries.
Polybrominated diphenyl ethers (PBDEs) -- used widely as flame-retardant additives in electronics and in polyurethane foam used for carpet padding, mattresses, chairs, sofas and other furniture -- have been detected in humans across the globe, but scientists are not certain how they are getting there.
"Our paper is the first U.S. market basket food survey for brominated flame retardants," says the study's lead author Arnold Schecter, M.D., M.P.H., an environmental health expert at the University of Texas' School of Public Health in Dallas.
Schecter and his coworkers tested 32 food samples from three major supermarket chains in Dallas. "We found PBDE contamination in all food containing animal fats," Schecter says, with the highest levels in fish, followed by meat and then dairy products. PBDEs are most soluble in fats, so they tend to accumulate in animal and human tissues.
Only two other similar market basket studies have been done -- in Spain and Japan -- and the U.S. levels were higher than both, according to the Texas study.
The Spanish study reported an upper level of 340 parts per trillion (ppt), while the most contaminated sample in the Texas study was a salmon filet with a concentration of more than 3,000 ppt. Likewise, the median concentration of PBDEs in meat from Dallas supermarkets was more than twice the maximum levels in meat from both the Spanish and Japanese surveys.
The researchers did not speculate on why levels in samples from Dallas supermarkets were higher than in the other two studies.
"Although these findings are preliminary, they suggest that food is a major route of intake for PBDEs," Schecter says.
The researchers recently reported high levels of PBDEs in breast milk of 47 women in Dallas and Austin -- the highest levels found in the world to date. They selected three major supermarket chains in Dallas for the new study and sampled well-known brands, assuming these were foods the women would probably have eaten.
It is important to note, however, that supermarkets in the United States often receive food from distant parts of the country. Schecter plans to extend the research to a larger study of foods from across the United States to better understand how people are exposed to flame retardants through their diets.
Little is known about the specific toxic effects of brominated flame retardants, but their increasing presence in human tissue is cause for concern because they have been associated with cancer, endocrine disruption and impaired brain development in animal studies, according to the researchers.
The European Union has banned two types of PBDEs -- the penta and octa formulations -- and is currently considering a ban on a third type, the deca formulation. Officials in the United States are still debating the fate of flame retardants, although the main U.S. manufacturer recently announced plans to discontinue production of the penta and octa formulations as part of a voluntary agreement with the U.S. EPA.
The American Chemical Society is a nonprofit organization, chartered by the U.S. Congress, with a multidisciplinary membership of more than 159,000 chemists and chemical engineers. It publishes numerous scientific journals and databases, convenes major research conferences and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.
-- Jason Gorss
The online version of the research paper cited above was initially published Sept. 1 on the journal's Web site and will appear in the journal's Oct. 15 print edition. Journalists can arrange access to the journal's Web site by sending an e-mail to firstname.lastname@example.org or calling the contact person for this release.