Peregrine Falcons Poisoned by Popular Flame Retardant
WASHINGTON, DC, January 7, 2004 (ENS) - Peregrine falcons were taken off the U.S. endangered species list just five years ago after recovering from the effects of organochlorine pesticides like DDT, but they may now be facing a new chemical threat. A Swedish study has determined that eggs of peregrine falcons in that country contain high levels of the world's most widely used brominated flame retardant, which scientists had thought could not enter the bodies of wildlife.
The Swedish falcon eggs studied contained some of the highest levels of brominated diphenyl ethers ever found in any kind of wildlife, and this was the first time that the deca formulation of BDE (deca-BDE) has been found in a living organism.
Falcons in North America are likely to face the same threat, the researchers say, because more than three times as much of the retardant was used in North America than in Europe.
The findings add to concern among some scientists that deca-BDE is not as harmless as previously thought.
The study examined three peregrine falcon populations in Sweden - two in the wild and one in captivity. Funded by the Swedish Society for Nature Conservation, the research appears in the current edition of "Environmental Science & Technology," a peer-reviewed journal of the American Chemical Society.
"We found high concentrations of all the different BDEs in both wild populations," says Cynthia de Wit, Ph.D., an associate professor at Stockholm University's Institute of Applied Environmental Research and lead author of the study. "The total concentrations of all the BDEs in the wild falcons are some of the highest seen in any wildlife globally."
Finding the deca form of BDE in the falcons was a surprise to the researchers since that formulation has been considered too big a molecule to cross cell membranes and be taken up by wildlife or humans. "This is the first time anyone has found deca in wildlife," de Wit says.
Aerial predators that can dive on their prey at speeds up to 200 miles per hour, peregrine falcons neared the brink of extinction after World War II. Their decline was blamed on organochlorine pesticides like DDT, which were linked to thin-shelled eggs that broke during incubation.
While BDEs do not produce the eggshell thinning associated with DDT, there has been some evidence of neurobehavioral problems from exposure to the chemicals in laboratory animals.
The main U.S. manufacturer of the products has announced its plans to phase out production of two BDE forms - the penta and octa versions as part of a voluntary agreement with the U.S. Environmental Protection Agency.
On November 3, 2003, Great Lakes Chemical Corporation announced that it will phase out U.S. production of the two chemicals by the end of 2004. Great Lakes is the sole U.S. manufacturer of penta BDE and octa BDE.
The the penta and octa forms of BDE will be banned in member states of the European Union beginning later this year.
The European Union recently conducted an environmental risk assessment on the deca form of BDE. In early December 2003 it concluded that deca poses an acceptably low risk and will not be banned.
But many scientists advocate a more cautious approach. "We discovered the DDT problem because bird populations crashed," de Wit says. "They still haven't completely recovered from DDT, so new effects could be masked. Or the BDE concentrations haven't gotten high enough yet to cause a recognizable effect."
In the United States, peregrine falcons now number around 1,600 breeding pairs, up from a low of only 19 breeding pairs in the 1970s.
"The fact that we have found [deca] in falcon eggs means that it is in their food, is taken up from the gut and is transferred to the eggs," de Wit says. "Thus, deca seems to cross cell membranes without too much trouble."
"The least that should be done is to reduce exposure, especially for humans," de Wit says. "Deca does not seem to be a very stable molecule and I am concerned that the release of huge amounts of deca over many years will lead to a buildup in the environment that will then slowly degrade to BDEs that are much more bioavailable."
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