Flame Retardants Linked to Fertility, Development Problems : Discovery News

THE GIST:

• High levels of certain flame retardants reduced women's odds of getting pregnant.
• Another study found that high levels of PBDE exposure in the womb was associated with lower scores on tests of mental and physical development.
• PBDEs are being phased out of use, but they persist in furniture foam, carpet backing, and many consumer electronics.

The first studies of widely used flame-retardants' effects on human health are emerging, and the evidence is not comforting. The compounds appear to affect women's fertility and children's physical and mental development.

The compounds in question are bromine-containing flame retardants, abbreviated PBDEs, which have been added to furniture foam, carpet pads and the plastics surrounding electronics like computers, cell phones, and televisions to comply with laws requiring a certain resistance to fire.

"The good news is that PBDEs are really being phased out," said Kim Harley of the University of California, Berkeley, who authored the study on fertility. Two types of PBDEs have not been used in new products in the United States since 2004, while the third type will be phased out by 2013.

"The bad news is that they are in these products that are long-term consumer goods," Harley said. "They are going to remain in our houses for the next little while."

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Her study measured PBDE levels in the blood of a group of women in California.

"Women with higher exposure to PBDEs took significantly longer to become pregnant," Harley said.

For every tenfold increase in blood PBDE levels, women had 30-50 percent lower odds of becoming pregnant each month. The range of measured levels covered one-thousand fold.

"In order to be eligible to be in our study, you had to become pregnant," Harley noted. "If we included infertile women, we could find an even stronger correlation."

Meanwhile, Julie Herbstman of Columbia University in New York and colleagues measured PBDE levels in the umbilical cord blood of 210 newborns to determine their prenatal exposure to PBDEs. She followed up with tests of physical, verbal and mental development from birth through age six.

"The kids with the highest prenatal exposures scored on average lower on the tests than the kids with lower exposures," she said.

Herbstman says the observed effects are similar to those from low-level lead exposure.

In both cases, researchers adjusted for confounding factors. Harley's study, for instance, was largely composed of Mexican immigrants working in agriculture, who might have had unusually high exposure to pesticides. Herbstman's study looked at women in Manhattan who were pregnant at the time of 9/11.

Neither of these factors affected the results, according to the teams' statistical analyses. But both authors say their findings need to be repeated in other groups.

"There haven't been a whole lot of human studies at this point, and that is why these first studies are interesting and important," Herbstman said.

Ninety-seven percent of Americans have detectable PBDEs in their blood, according to the study. Americans have 20 times higher levels than Europeans, because of strict U.S. laws requiring fire retardant use, especially in California. Average levels in Americans have doubled every four to six years since the 1970s, say the researchers.

"Not to lessen the significance of the results here, but we need to recognize that these results reflect on a product which is no longer made," said Ray Dawson of Albemarle Corporation, a major U.S. flame retardant manufacturer.

One of the products that will replace PBDEs is a group of chlorinated phosphate flame retardants. These have also raised concerns, with some research claiming they lead to DNA mutations, although Dawson maintains they are safe.

These products have undergone a thorough risk assessment," he said. "The risk associated with these chlorinated phosphates is minimal. It is acceptable."

And, he adds, flame retardants serve an important purpose.

"They save lives," he said. "Fire safety is a key issue. The key element is that we use flame retardants that are safe."

via news.discovery.com

Posted via email from Moments of Awareness