Newer chemicals found in wildlife: supposedly safer flame retardants turning up in falcon eggs.
Two chemicals that are replacing potentially toxic flame retardants in products such as TVs and furniture have shown up in peregrine falcon eggs in California.
While the replacement compounds were found in much smaller quantities than the older generation of flame retardants, their presence in bird eggs is cause for concern, said June-Soo Park of the California Environmental Protection Agency in Berkeley. Little is known about the toxicity of the replacements and their potential to accumulate in people and wildlife, said Park, who presented the new research March 25.
Fire retardants of the earlier generation, known as polybrominated diphenyl ethers, or PBDEs, were added to household products such as furniture, electronics and carpeting to reduce fire-related injuries. "We don't want kids' pajamas catching on fire," said Sarah Rubinfeld of Stanford University.
In California, which has especially stringent product flammability laws, people and wildlife contain some of the highest PBDE levels in the world, Park noted. Research on animals suggests that many PBDEs mimic the effects of thyroid hormones, meddling with reproduction and nerve and tissue development. Two of the most common formulations have been banned in California since 2006.
But researchers are still finding PBDEs in the environment, where their replacements--hexabromobenzene, known as HBB, and Bis(2,4,6,-tribromophenoxy) ethane, known as BTBPE--are also now showing up.
Park's team has been studying peregrine falcons, which were endangered by pesticides such as DDT but have recovered in much of the United States. These predatory birds are considered sentinels of environmental health.
Park and his colleagues measured levels of contaminants in eggs and chicks from 38 nest sites between 1986 and 2007. In the eggs, PBDE levels more than tripled each decade, Park noted.
Data suggest that the new flame retardants are also accumulating in wildlife, Park reported. The research team detected HBB and BTBPE in 19 falcon eggs, but at much lower quantities than the old standby chemicals. It isn't clear how the falcons accumulate the new flame retardants, Park said. Other scientists have reported finding HBB in herring gulls around the Great Lakes and BTBPE in dust samples from bedrooms and living rooms in the Boston area.
The replacement flame retardants are considered safer because they don't break down as readily into absorbable forms, but the flip side is that they may persist for a long time.
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|Date:||Apr 24, 2010|
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